Many thanks to SWLing Post contributor, 13dka, who shares the following guest post:
Gone fishing…for DX: Reception enhancement at the seaside
In each of my few reviews I referred to “the dike” or “my happy place”, which is a tiny stretch of the 380 miles of dike protecting Germany’s North Sea coast. This is the place where I like to go for maximum listening pleasure and of course for testing radios. Everyone knows that close proximity to an ocean is good for radio reception…but why is that? Is there a way to quantify “good”?
Of course there is, this has been documented before, there is probably lots of literature about it and old papers like this one (click here to download PDF). A complete answer to the question has at least two parts:
1. Less QRM
It may be obvious, but civilization and therefore QRM sources at such a place extend to one hemisphere only, because the other one is covered with ocean for 100s, if not 1000s of miles. There are few places on the planet that offer such a lack of civilization in such a big area, while still being accessible, habitable and in range for pizza delivery. Unless you’re in the midst of a noisy tourist trap town, QRM will be low. Still, you may have to find a good spot away from all tourist attractions and industry for absolutely minimal QRM.
My dike listening post is far enough from the next small tourist trap town (in which I live) and also sufficiently far away from the few houses of the next tiny village and it’s located in an area that doesn’t have HV power lines (important for MW and LW reception!) or industrial areas, other small villages are miles away and miles apart, the next town is 20 km/12 miles away from there. In other words, man-made noise is just not an issue there.
That alone would be making shortwave reception as good as it gets and it gives me an opportunity to check out radios on my own terms: The only way to assess a radio’s properties and qualities without or beyond test equipment is under ideal conditions, particularly for everything that has to do with sensitivity. It’s already difficult without QRM (because natural noise (QRN) can easily be higher than the receiver’s sensitivity threshold too, depending on a number of factors), and even small amounts of QRM on top make that assessment increasingly impossible. This is particularly true for portables, which often can’t be fully isolated from local noise sources for a couple of reasons.
Yes, most modern radios are all very sensitive and equal to the degree that it doesn’t make a difference in 98% of all regular reception scenarios but my experience at the dike is that there are still differences, and the difference between my least sensitive and my most sensitive portable is not at all negligible, even more because they are not only receivers but the entire receiving system including the antenna. You won’t notice that difference in the middle of a city, but you may notice it in the woods.
When the radio gets boring, I can still have fun with the swing and the slide!
2. More signal
I always had a feeling that signals actually increase at the dike and that made me curious enough to actually test this by having a receiver tuned to some station in the car, then driving away from the dike and back. Until recently it didn’t come to me to document or even quantify this difference though. When I was once again googling for simple answers to the question what the reason might be, I stumbled upon this video: Callum (M0MCX) demonstrating the true reason for this in MMANA (an antenna modeling software) on his “DX Commander” channel:
To summarize this, Callum explains how a pretty dramatic difference in ground conductivity near the sea (click here to download PDF) leads to an increase in antenna gain, or more precisely a decrease in ground return losses equaling more antenna gain. Of course I assumed that the salt water has something to do with but I had no idea how much: For example, average ground has a conductivity of 0.005 Siemens per meter, salt water is averaging at 5.0 S/m, that’s a factor of 1,000 (!) and that leads to roughly 10dB of gain. That’s right, whatever antenna you use at home in the backcountry would get a free 10dB gain increase by the sea, antennas with actual dBd or dBi gain have even more gain there.
That this has a nice impact on your transmitting signal should be obvious if you’re a ham, if not just imagine that you’d need a 10x more powerful amplifier or an array of wires or verticals or a full-size Yagi to get that kind of gain by directionality. But this is also great for reception: You may argue that 10dB is “only” little more than 1.5 S-units but 1.5 S-units at the bottom of the meter scale spans the entire range between “can’t hear a thing” and “fully copy”!
A practical test
It’s not that I don’t believe DX Commander’s assessment there but I just had to see it myself and find a way to share that with you. A difficulty was finding a station that has A) a stable signal but is B) not really local, C) on shortwave, D) always on air and E) propagation must be across water or at least along the shoreline.
The army (or navy) to the rescue! After several days of observing STANAG stations for their variation in signal on different times of the day, I picked one on 4083 kHz (thanks to whoever pays taxes to keep that thing blasting the band day and night!). I don’t know where exactly (my KiwiSDR-assisted guess is the English channel region) that station is, but it’s always in the same narrow range of levels around S9 here at home, there’s usually the same little QSB on the signal, and the signals are the same day or night.
On top of that, I had a look at geological maps of my part of the country to find out how far I should drive into the backcountry to find conditions that are really different from the coast. Where I live, former sea ground and marsh land is forming a pretty wide strip of moist, fertile soil with above average conductivity, but approximately 20km/12mi to the east the ground changes to a composition typical for the terminal moraine inland formed in the ice age. So I picked a quiet place 25km east of my QTH to measure the level of that STANAG station and also to record the BBC on 198 kHz. Some source stated that the coastal enhancement effect can be observed within 10 lambda distance to the shoreline, that would be 730m for the 4 MHz STANAG station and 15km for the BBC, so 25km should suffice to rule out any residue enhancement from the seaside.
My car stereo has no S-meter (or a proper antenna, so reception is needlessly bad but this is good in this case) so all you get is the difference in audio. The car had the same orientation (nose pointing to the east) at both places. For the 4 MHz signal though (coincidence or not), the meter shows ~10dBm (or dBµV/EMF) more signal at the dike.
3. Effect on SNR
Remember, more signal alone does not equal better reception, what we’re looking for is a better signal-to-noise ratio (SNR). Now that we’ve established that the man-made noise should be as low as possible at “my” dike, the remaining question is: Does this signal enhancement have an effect on SNR as well? Even if there is virtually no local QRM at my “happy place” – there is still natural noise (QRN) and that wouldn’t that likely gain 10dB too?
Here are some hypotheses that may be subject of debate and some calculations way over my head (physics/math fans, please comment and help someone out who always got an F in math!). Sorry for all the gross oversimplifications:
Extremely lossy antennas
We know that pure reception antennas are often a bit different in that the general reciprocity rule has comparatively little meaning, many antennas designed for optimizing reception in specific situations would be terrible transmitting antennas. One quite extreme example, not meant to optimize anything but portability is the telescopic whip on shortwaves >10m. At the dike, those gain more signal too. When the QRN drops after sunset on higher frequencies, the extremely lossy whip might be an exception because the signal coming out of it is so small that it’s much closer to the receiver noise, so this friendly signal boost could lift very faint signals above the receiver noise more than the QRN, which in turn could mean a little increase in SNR, and as we know even a little increase in SNR can go a long way.
The BBC Radio 4 longwave recording is likely another example for this – the unusually weak signal is coming from a small and badly matched rubber antenna with abysmal performance on all frequency ranges including LW. The SNR is obviously increasing at the dike because the signal gets lifted more above the base noise of the receiving system, while the atmospheric noise component is likely still far below that threshold. Many deliberately lossy antenna design, such as flag/tennant, passive small aperture loops (like e.g. the YouLoop) or loop-on-ground antennas may benefit most from losses decreasing by 10dB.
Not so lossy antennas, polarization and elevation patterns
However, there is still more than a signal strength difference between “big” antennas and the whips at the dike: Not only at the sea, directionality will have an impact on QRN levels, a bidirectional antenna may already decrease QRN and hence increase SNR further, an unidirectional antenna even more, that’s one reason why proper Beverage antennas for example work wonders particularly on noisy low frequencies at night (but this is actually a bad example because Beverage antennas are said to work best on lossy ground).
Also, directional or not, the “ideal” ground will likely change the radiation pattern, namely the elevation angles, putting the “focus” of the antenna from near to far – or vice versa: As far as my research went, antennas with horizontal polarization are not ideal in this regard as they benefit much less from the “mirror effect” and a relatively low antenna height may be more disadvantageous for DX (but maybe good for NVIS/local ragchewing) than usual. Well, that explains why I never got particularly good results with horizontal dipoles at the dike!
Using a loop-on-ground antenna at a place without QRM may sound ridiculously out of place at first, but they are bidirectional and vertically polarized antennas, so the high ground conductivity theoretically flattens the take-off angle of the lobes, on top of that they are ~10dB less lossy at the dike, making even a LoG act more like something you’d string up as high as possible elsewhere. They are incredibly convenient, particularly on beaches where natural antenna supports may be non-existent and I found them working extremely well at the dike, now I think I know why. In particular the preamplified version I tried proved to be good enough to receive 4 continents on 20m and a 5th one on 40m – over the course of 4 hours on an evening when conditions were at best slightly above average. Though the really important point is that it increased the SNR further, despite the QRN still showing up on the little Belka’s meter when I connected the whip for comparison (alas not shown in the video).
The 5th continent is missing in this video because the signals from South Africa were not great anymore that late in the evening, but a recording exists.
Here’s a video I shot last year, comparing the same LoG with the whip on my Tecsun S-8800 on 25m (Radio Marti 11930 kHz):
At the same time, I recorded the station with the next decent KiwiSDR in my area:
Of course, these directionality vs noise mechanisms are basically the same on any soil. But compensating ground losses and getting flat elevation patterns may require great efforts, like extensive radial systems, buried meshes etc. and it’s pretty hard to cover enough area around the antenna (minimum 1/2 wavelength, ideally more!) to get optimum results on disadvantaged soils, while still never reaching the beach conditions. You may have to invest a lot of labor and/or money to overcome such geological hardships, while the beach gives you all that for free.
But there may be yet another contributing factor: The gain pattern is likely not symmetrical – signals (and QRN) coming from the land side will likely not benefit the same way from the enhancement, which tapers off quickly (10 wavelengths) on the land side of the dike and regular “cross-country” conditions take place in that direction, while salt water stretching far beyond the horizon is enhancing reception to the other side.
So my preliminary answer to that question would be: “Yes, under circumstances the shoreline signal increase and ground properties can improve SNR further, that improvement can be harvested easily with vertically polarized antennas”.
Would it be worthwhile driving 1000 miles to the next ocean beach… for SWLing?
Maybe not every week–? Seriously, it depends.
Sure, an ocean shoreline will generally help turning up the very best your radios and antennas can deliver, I think the only way to top this would be adding a sensible amount of elevation, a.k.a. cliff coasts.
If you’re interested in extreme DX or just in the technical performance aspect, if you want to experience what your stuff is capable of or if you don’t want to put a lot of effort into setting up antennas, you should definitely find a quiet place at the ocean, particularly if your options to get maximum performance are rather limited (space constraints, QRM, HOA restrictions, you name it) at home.
If you’re a BCL/program listener and more interested in the “content” than the way it came to you, if you’re generally happy with reception of your favorite programs or if you simply have some very well working setup at home, there’s likely not much the beach could offer you in terms of radio. But the seaside has much more to offer than fatter shortwaves of course.
From left to right: Starry sky capture with cellphone cam, nocticlucent clouds behind the dike, car with hot coffee inside and a shortwave portable suction-cupped to the side window – nights at the dike are usually cold but sometimes just beautiful. (Click to enlarge.)
However, getting away from the QRM means everything for a better SNR and best reception. In other words, if the next ocean is really a hassle to reach, it may be a better idea to just find a very quiet place nearby and maybe putting up some more substantial antenna than driving 1000 miles. But if you happen to plan on some seaside vacation, make absolutely sure you bring two radios (because it may break your heart if your only radio fails)!
Many thanks to SWLing Post contributor, 13DKA, who shares the following guest post:
From Belarus with love: The Belka DSP
by 13DKA (international man of mystery)
I do have a thing with tiny radios. However, the Belka DSP is so very, very tiny and disguised in understatement that it squirreled itself out of my sight for a while. There wasn’t a lot of information when I took notice of its existence last year, having to order it from a Cyrillic script website prevented an impulse purchase and to be honest, I didn’t think that a shortwave receiver so small could do anything as good or even better than the radios I already own. Then, when this fine blog spread the news about the Mobimax.bg shop in Bulgaria offering this radio, I started another research and I learned that I’m not the only one who had some serious misconceptions about the little squirrel. (“Belka” = “squirrel” in Russian).
The outside: Spy radio reloaded
Admittedly, the tiny metal box with 4 buttons and a (metal) knob, antenna, headphone and a micro USB jack on the side, bringing less than 100 grams onto the scale, in a size that could make this radio as hard to find as your car keys may look like something that must have traded functionality for size. This is no doubt a solid little piece of gear though, one that doesn’t try to be anything but functional.
The form factor could be described as “bigger than a box of matches but smaller than a pack of cigarettes” to the ex- and still-smokers, and the elderly people among us who watched all the classic spy flicks out there may inevitably associate it with “spy radio”. It’s not quite 007’s clothes brush communicator or the U.N.C.L.E. pen radio but it would sure beat classic spy radio equipment which could be anything from a suitcase full of electronics to small boxes with comparatively few transistors in it, and they all wouldn’t have lasted much longer than it takes to be killed by 007 before the batteries would run out of juice.
The Belka DSP is very different from those, while it could possibly be smuggled into the country in a shoe heel, it boasts an endurance of 18h and it consists of 100,000s of transistors due to its highly integrated and low-power consuming electronics. These innards deserve some examination, because there seems to be some confusion about the nature of this radio out there on the interwebz:
Much bigger inside – technicalities:
It seems that some people read “DSP”, see the price and automatically dismiss it as yet another SiLabs 473x radio like many of the bargain Chinese shortwave portables, and the Belka’s miniscule size may suggest that it might not be the best of them either. Some presumed it’s based on an RTL chip… but that’s all as far from the truth as it gets. For starters, said Chinese radios, albeit digitally controlled, are actually still “conventional” analog radios which employ digital signal processing only at some varying later stage in the circuit and use only parts of the many features provided by the SiLabs chip (of which DSP is only a part), some even still rely on analog ceramic IF filters and use the chip only to provide AM/FM (e.g. PL-6xx). If they do use the DSP features, that’s how some end up as “triple conversion” receivers – 2 conventional IF stages with a 3rd, DSP IF stage – and some common quirks.
The Belka DSP, on the other, hand is not exactly a conventional radio to begin with but a basic (“direct conversion”) SDR. If I interpret the information on this site correctly, the only Silicon Labs chip used is a Si5351A multi-clock generator to provide high-precision oscillators to be fed into some TI chips serving as the quadrature detector/mixer, their output is then processed in a pretty decent ADAU1761 audio DSP (24-bit AD/DA), a PIC is controlling all that, and a 1W audio amplifier IC (TS4890) is providing the needed power to drive headphones or a passive external speaker directly. One comment somewhere was putting it in the same category as the Commradio CR-1 and while there’s some truth to it in some way, that’s not quite right either because the Belka DSP doesn’t use some pre-fabricated and re-dedicated TV tuner chip. While the functional principle may be similar, the Belka is made out of “discrete” components.
The different architecture also explains why it has so little in common with the Chinese DSP radios, there’s no muting, chuffing or hissing, no “softmute” or similar slightly malfunctioning attempts at making the radio appear quieter than it actually is, no distortion due to a seemingly uncurable lazy AGC… Instead, everything is predictable, precise (frequency!) and quiet and it behaves and sounds like a classic communications receiver or any reasonable piece of modern ham radio gear.
The Belka DSP ships with a detachable (BNC) 74cm/29″ short telescopic whip, and the receiver is said to be designed to develop full sensitivity with that whip. This may be raising some apprehension about how it would perform on full-sized antennas, but most of the YouTube videos about this radio demonstrate it with all kinds of passive and active antennas and (almost) surprisingly the Belka DSP appears to cope just fine with them, which in turn made me concerned about how good it could be on its whip – I mean it can’t be super-sensitive on a whip and have a decent dynamic range and be cheap all at the same time, right? How does it compare to the typical Chinese portables it’s being confused with? Do I need this radio anyway?
Q would be jealous – performance
Meaningful technical data beyond what’s provided on the purchase pages is hard to find. For example, Fenu Radio has listed the MDS (= minimum detectable signal) threshold as “-135 dBm” (without stating a source), whereas MDS was possibly taken synonymous for noise floor. A Russian YouTube radio channel seems to have actually measured an excellent sensitivity of 0.16µV on 40m in SSB. These would be rather typical figures for such a design and that would make it a quiet and sensitive radio indeed.
My other portables, on the other hand, don’t come with any specs beyond frequency range and features and the proof is in the pudding anyway. Let’s go north by northwest (the correct compass point name would be “northwest by north” BTW) to the secret 13DKA proving ground at the dike to find out if it shows!
Actually I took it to the dike on several days/evenings/nights during the past 4 weeks to test it under varying conditions, to compare it with different radios and to serve as a nutrition source for the local lady mosquitos. The first one I took to the dike was my XHDATA D-808, it seemed like a natural candidate to compare with the Belka because I would use both in the same role – as a very sensitive “wearable” shortwave receiver to carry around on walks. To summarize that quickly – while the D-808 is already a sensitive radio, the difference between the two is represented pretty well by this short audio clip I picked out of many – this is Radio New Zealand International on 13840 kHz, 2 hours before midnight local time (UTC +2):
[No time indications needed here. The portions with mostly noise: D-808, When you hear someone talking: Belka]
So the Belka won the competition for the intended purpose already and it wasn’t exactly a “photo finish” either…mission accomplished, case closed, end of the review, thank you for reading. But… how would it compare to the S-8800, the most sensitive and quiet of my Chinese DSP radios? I felt like this would be an unfair comparison, I mean c’mon, the Tecsun’s whip is almost twice as long as the Belka’s…
So to level the field, I compared them with my favorite lazy makeshift antenna: A few meters of litz wire coupled (inductively) to an old 24ft steel flagpole on my “proving ground”, connected to the radios with a short stretch of coax to shield the “hot” wire inside the car. Not exactly a proper antenna but it would do to compare the radios better and I used this contraption to boost signals (a lot!) in the past years with great success. Indeed, the radios performed very similar on this contraption in terms of sensitivity, so there was no clear winner in this regard. Then on a hot, sunny day I decided to spend the afternoon at the beach with the Belka and the other radios, this time letting the Belka and the S-8800 run against each other on their whips only. To my surprise, the beneficiary of the external antenna the other day was the Tecsun, not the Belka! But let’s break this up into the different modes:
On the Belka DSP, “15,000 kHz” means 15,000.000 kHz, not 15,000.030 or 14,999.790 or worse, no matter how you shake it or where you touch it, it’s dead-on on WWV or many well-maintained broadcast transmitters and calibration or regular retuning is not necessary. Of course it doesn’t have trouble suppressing the other sideband, LSB and USB sound and behave absolutely identical/symmetrical and demodulation, even of strong stations is free of artifacts. This is SSB (or ECSS) reception how it’s supposed to be.
Of all my Chinese portables, only the S-8800 could come close to that “analog” feeling when turning the VFO knob, or particularly its fine-tuning knob with 10-50Hz steps …if that fine-tuning knob wouldn’t cause a terrible frequency jitter while tuning and if the AGC wouldn’t cause clipping and if the BFO had even remotely the stability of the Belka. In the following audio clips you may notice that the Tecsun is slightly off frequency most of the time – after retuning the radio for the 10th time because the sun sets and the air temperature is dropping slowly, I usually stop caring about that.
These clips were all recorded with the S-8800 @2.3 kHz and the Belka @2.4kHz bandwidth. Please, if you really want to hear the differences do yourself a favor and use some headphones or external speakers with some decent bass response, otherwise the important bits may get lost (like on my laptop speakers):
– This is the Gander/NY VOLMET on 10051 kHz the night I used the external antenna:
[0:00: Tecsun, 0:15: Belka]
– Here’s Argentina (LU6FOV) in QSO with Scotland (GM1DSK) on 20m around midnight:
[0:00: Tecsun, 0:18: Belka]
– Same band, a ham in Louisiana later that night:
[0:00: Tecsun, 0:15: Belka]
– 75m after midnight, ragchewing guy from NC on 3927 kHz (alas a noisy band at this time of the year):
[0:00: Belka, 0:15: Tecsun, 0:30: Belka]
Here are a few clips with the radios only using the whip, both recorded on 20m around sunset, when the atmospheric noise was finally going down and the band was slowly closing, at least for north-south propagation paths. Like I mentioned above, the Tecsun with its long whip and great independency from a counterpoise etc., clearly won the comparison with my other portables a few years ago and I was really expecting it to beat the Belka.
– ZS1OPB near Cape Town, South Africa in QSO with an unknown OM, possibly in Scandinavia or Germany. The latter has a pretty borderline intelligible signal, and it shows when switching to the Tecsun:
– Here’s KB3RHR calling CQ even later on 20m, which had just dropped into the quiet period between daytime and the South America route greyline enhancement:
[Again, no time indication needed!]
CW is another mode where the Belka shows how it’s different in that it has a dedicated CW mode to begin with. Most of the portables based on a SiLabs 4735 come with typical CW filter bandwidths like 500Hz, but to receive CW you may have to switch to USB, then to the proper bandwidth first. The Belka DSP has a dedicated CW mode doing these settings for you and a way, way superior 300Hz filter. The passband of that filter can be shifted in 100 Hz-steps between 500 Hz and 1 kHz to match your favorite tone pitch. CW reception is like you’d expect it from a regular ham RX/TRX, proper AGC action, proper filter, no artifacts, clean tone. Tuning through the band with 10, 50 or 100 Hz steps is smooth, quick, easy and fun. While there are of course tiny QRP transceivers particularly for CW, I’m almost sure that this level of CW goodness in such a small general coverage all-mode receiver hasn’t been seen before.
Here’s all 3 radios in one go. I deliberately picked a frequency with someone producing terrible clicks to the left and another pretty loud station to the right:
I think it’s awesome that the multi-banders kind of cover CW now but as you can likely hear, CW is also where the inherent (chip-related) and newly acquired (wanderlusty BFO on the S-8800) shortcomings of the Chinese radios are most obvious. Both distort on the onset of AGC action of course and turn a pure-ish sine CW signal waveform into some more square-ish shape thereafter and their “500 Hz” filters are letting a lot of signals through from beyond the filter slopes, which makes me think that setting is maybe not really meant to be used for CW. In the Tecsun example at 0:21 I had to use the fine-tuning knob and you’ll also hear the S-8800’s strange quirk with trying to mute the audio, despite soft-/automute is being turned off in the “hidden” settings. The D-808 is less quirky and very stable but using the fine-tuning knob to scan the CW segments on the bands is rather tedious with it, because it doesn’t tune the radio continuously and just jumps back to -99 on the same frequency once you reached +99.
When I saw this on the specs list, I thought this must be some error. On second thought it was pretty obvious: A proper shortwave receiver designed by a ham (Alex, EU1ME) for hams (among others of course) must be capable of receiving the local 10m-band FM repeater and of course you could also enjoy European 40-channel CB radio with that. Many ambitious tabletop receivers of the past had that option too. While this is nice, a squelch is more or less mandatory for FM or the listening pleasure will have its limits, and the Belka DSP does not have one. Unfortunately the next FM repeater is too far away, so is the next proper 10m-band opening and to receive any CB (apart from freebanders worldwide around 27,555 kHz USB) in my neck of the woods I have to be very, very lucky and I never managed to hear anything local with any of the portables. By coincidence, on the 2nd test evening on the dike I did pick up some CB stations in FM with the Belka and it did a great job, given the faint (but domestic) signals I got out there. So, the FM function was unsurprisingly tested OK and much more surprisingly, the FM noise is rather untypically unobtrusive.
Noteworthy: NFM has the same filter options as the other modes, so unlike aforementioned receivers with FM option or a dedicated CB radio, you can try a narrower filter setting which can improve SNR on FM (at the cost of some more distortion) in order to dig a weak station a bit more out of the mud.
Receiving international SW broadcasters is what almost all, even some particularly cheap SW portables do quite well. Of course, like any decent receiver aiming for demanding hobbyists, spies and other commercial users alike, the little squirrel is even apt for more elusive DX, due to its versatile filters, stability and sensitivity. On top of that it sports what the manual calls “pseudo-synchronous detection”. I can foresee people misunderstanding this, so I think this could use a bit of an explanation:
Alex likely didn’t use this somewhat unwieldy term for no reason, instead of just putting a slightly misleading “sync detection” on the feature list: To put my limited understanding in simple words, regular sync detection is extracting the modulation content from the carrier, then replacing the original carrier that was battered by the ionosphere with a phase-locked, fresh and stable one from an oscillator, and finally bringing that back together with the modulation content.
“Pseudo sync” does the same except it doesn’t use an oscillator and a phase-lock-loop to recreate the carrier, instead it regenerates the original carrier by squashing it in some limiting amplifier to stabilize it and remove the modulation content. This is a quite smart and parts-saving arrangement and it’s inherently in phase with the signal. But that also means the original carrier must be somewhat intact, the less damage it has taken the better, while the “true” sync detector doesn’t rely on the original carrier and the signal can be reconstructed as long as modulation could be extracted.
That explains why recovering ultra-weak and downright broken signals from clandestine stations at the other end of the globe may not be the strength of a “pseudo-sync” detector, on the Belka it may even desensitize the radio and you will hear less than without…unless the opposite happens. Like with any sync detector I’ve tried so far, sometimes it works, sometimes it won’t. What always works is improving reception of stations that still have some headroom, mitigating phasing effects and making it generally a little more comfy to listen to and I think the Belka’s sync detector does that very well but unobtrusively. It’s usually hard to asses whether or not a sync detector helped with a particular dip in the signal or not, unless you have 2 specimen of the same radio to record their output simultaneously and compare.
ECSS (Exalted Carrier Single Sideband)
Besides the “pseudo-sync” detector, the Belka’s excellent frequency precision and stability also makes the technically similar sideband-reception of AM broadcasts a no-brainer: Just switch to USB or LSB and if the transmitter itself isn’t badly off frequency, that’s all you need to do because the radio is dead-on on the frequency, LSB or USB.* Since the available filter settings are the same for all modes (other than CW), you can also use the widest filter setting for maximum fidelity in ECSS. In comparison, all of the Chinese portables I have (and most if not all of the Chinese, Korean or Japanese portables I owned in the past) need some fine tuning to zero in on the station, each meter-band and each sideband their own setting and some just lacked the stability to stay zeroed in.
*With a tuning resolution of 10Hz, it’s technically impossible to entirely “zero-beat” a station with an offset other than exactly 10 Hz or multiples thereof. However, a small residue beat of a few Hz isn’t that bad and the ability to select the sideband suffering the least interference, the recovered modulation content and the decreased noise through narrower bandwidth still make ECSS a great way to improve reception.
AM reception examples
…beginning with some clips captured using the external antenna:
– This is RHC 5040 kHz, shortly after fading in after midnight local time, followed by some music from Radio Rebelde on 5025 kHz. The Belka’s 2.4 kHz filter setting has not only 100 Hz more bandwidth but also a much more presence-friendly shape than the Tecsun’s rather muffled sounding 2.3 kHz filter. The other notable difference is some high frequency hiss the Tecsun likes to emit, it becomes more evident when the channel noise doesn’t play such a significant role anymore, like on AM:
– Next is CHU 7850 kHz. While CHU is technically transmitting AM with one sideband suppressed (H3E) I threw those in this category, even though at the end I switched the radios to USB to demonstrate the SNR gain this means for both radios:
– CHU again, but now on a late afternoon on 14 MHz with really bad condx and with the radios [b]using their whips[/b]. Unfortunately I lost the clip with the Tecsun in USB but if you consider how little CHU you hear from it in AM, you can probably imagine that it wasn’t that much better in USB:
– Finally 2 clips (again using the whips only) taken from a German station with the imaginative moniker “Shortwave Radio” (www.shortwaveradio.de) transmitting from a site little more than 100 miles from here on 3975 kHz, in the afternoon. Despite the station being so close to my QTH, there’s some pronounced fading on it that makes the Tecsun suffer a bit more than the Belka:
[Left channel: Belka, right channel: Tecsun]
– Same station, but now with both radios switched to wide filters (4.7 on the Belka and 4.0 on the Tecsun):
[Left channel: Belka, right channel: Tecsun]
It’s very subtle but I find the Belka presents AM signals with less harshness and distortion and a more “solid” feel to it. Please note that these clips were recorded with a cellphone (with some decent built-in stereo mic though) and I used my CC Radio 2E as a powered speaker for the speakerless Belka, which is admittedly a great combination.
The Belka has one variable IF filter, whereas both low and high cutoff frequencies can be adjusted for each mode individually and will be memorized for SSB, CW, AM and NFM individually. If you ever played with a more recent SDR, you’ll know what to expect from the filter.
While this perceived superiority over conventional filters may be subject to heated discussions among radio connoisseurs, it will beat whatever cheap ceramic filters usually ended up in consumer-level portables and low-end to mid-range tabletop shortwave receivers and it also beats what the aforementioned Chinese DSP radios have to offer in filter quality and flexibility. For example, those come with pre-defined settings, with arbitrary, varying and not always great sounding filter shapes and lower filter skirts tending to roll off the signal a bit too high for my taste, which can be both an advantage and a disadvantage depending on the signal: Some ham operators put considerable amounts of energy into a fat sounding bass. With a filter roll-off around 200 Hz and a weak signal, only a small remainder of modulation will make it to the speaker and you may not even notice that there’s a station while you tune the band*. With the filter reaching down to 100 Hz or even lower, that station’s existence will be immediately obvious and the now more complete modulation content could even be somewhat more intelligible. On the other hand, when splatter from a neighbor channel is creating a lot of rumble you’re happy if the lower edge of the passband can be shifted upwards.
What the Belka’s filter doesn’t quite match is the variety – some the latest China-portables have many presets including 1.7, 1.2 and 1 kHz while the lowest upper filter frequency you can get on the Belka DSP is 2.4 kHz. While this is consistent with common ham radio rigs, I find a filter <2 kHz quite useful on crowded SSB bands. Given the great presence and intelligibility the 2.4 kHz setting provides and the filter not entirely (95%) passing my “4XZ” test, where the filter has to suppress 4XZ’s CW signal on 6407 kHz while the radio is tuned to 6604 USB (Gander/NY VOLMET), maybe 2.3 kHz would have been better for optimum (but in the ham bands very theoretical) channel separation. This is some high level nitpicking for a radio that costs less than one plug-in filter for a Japanese transceiver though.
In AM, the shown filter bandwidths are per-sideband like on some other DSP radios, which equals “audio bandwidth”. That means you have to multiply the number by 2 to get an AM IF filter bandwidth figure comparable to conventional radios with “tangible” filters, the 2.4 kHz setting would be a 4.8 kHz filter and 4.7 means 9.4 kHz.
The Belka has a properly working AGC, but it seems to reflect the radio’s emphasis on SSB: It has a fixed, slow release constant for SSB reception and that appears to be in effect also on AM. Actually, the AGC release time is quite slow (2+ seconds?), just as slow as I would have preferred it if I’ve had a choice, however, this can turn out less than optimal in rare cases of fast fading intervals on an AM station. But that’s still way better than having to live with a fast AM AGC setting on SSB, and it doesn’t really diminish the general AM listening experience with the Belka for me, which I find quite a joy. Being able to listen to SSB stations without compromises for a change and not having to cut the radios some extra slack when they do not quite behave like normal radios is actually a relief.
This may reach into the “signal handling” category, but the Belka does also not exhibit any AGC pumping effects when a loud station is on a neighbor channel. For comparison, this is one of the issues that make the D-808 a little more uncomfortable, particularly on SSB – the constant change and modulation of noise and signals, often triggered by strong signals quite far away at the other end of a band or even worse in another band not exactly nice. Even the S-8800 tends to emit soft modulations or sudden faint hisses in response to stations booming in outside of the IF passband. It’s the sum of all those little behavioral bits that make the Belka play in a different league.
Signal handling capabilities:
Despite being so small, the Belka appears to have 3 bandpass filters for preselection of its coverage range, which is one more than for example the SDRPlay RSP SDRs have in the shortwave part of their coverage. However, all you need is 2 hefty signals within a frontend passband to put a radio’s dynamic range to a practical test. I don’t have any test equipment to quantify this robustness precisely, but I happen to have some big guns transmitting (often simultaneously) on several frequencies in the 41 and 31m bands at night over here, producing signals that none of my portables can swallow without hopelessly overloading when those signals (from sizeable dipoles/loops etc.) peak. In most nights at least one of these stations makes the virtual meter needle hit the stop pin (see screenshot above) and then my RSP SDRs start acting up as well.
Being too lazy Lacking the time to put up a proper “big” antenna at the dike, I simply tried a loop-on-ground with pretty substantial 60ft/20m circumference and a MegaLoop preamp deliberately left at its high gain setting, which was coincidentally just the right amount of trouble for the Belka. Here’s a video showing what was piling up on 41 and 31m in the hours before midnight local time (UTC+2) during the test:
I could’ve missed that if I hadn’t explicitly checked the broadcast bands neighborhood for it, but the Belka did show some mild signs of overloading: there were faint intermodulation products on some out-of-band frequencies and there was some very subtle onset of cross-modulation on e.g. Gander Radio 10,051 kHz, manifesting itself in some “rough” modulation:
[0:00: Tecsun cross-modulation, 0:22: Belka (slightly roughened up modulation)]
In the video, you can see that it was worse in the broadcast bands containing the offending signals (9635 kHz is an example and alas I didn’t check if the OTH radar signal on interfering on 9700 kHz was really there or not). This was however nothing compared to the S-8800, which really started acting up despite its improved frontend. This could be mitigated by using the “Local” switch (which I presume only turns off the input RF amp) on the Tecsun and given that the Belka doesn’t have any means of keeping overloads in check it’s a particularly good thing that it wasn’t anywhere near this level of misbehavior. I should also mention that I was scanning particularly the 40 and 20m ham bands the entire evening, and I didn’t notice any signs of overloading there while RRI, CRI, Vo Turkey and company were blasting the broadcast bands at the same time.
While the Belka doesn’t have a switchable preamp or even an attenuator like some multi-banders, it has a fully adjustable “sensitivity” control, a.k.a. “RF gain”. It’s useful even when using the whip only, because turning it down is effectively putting the radio in “manual” gain control mode and listening to a couple of strong stations with the noise turned way down and without the AGC pulling the schmutz back up is so much more relaxing. Unfortunately, RF gain controls never really help with an overloading frontend.
However, the Belka apparently takes a lot of a beating for a portable but maybe it should be duly noted that none of these radios are really meant to (fully) replace tabletop radios and that the little Belka is so good that it can be used in that role shouldn’t be leading to unrealistic expectations. If need be, there are affordable (<$20) attenuators built into male-female BNC adapters available and I think a -10dB type should suffice in most cases, -20dB if you can’t resist alligator-clipping the Eiffel tower to the Belka.
For your eyes only: Signal indicator and a display that speaks to me
The display is very readable from most angles and the bright backlight can be switched permanently on, off or to the usual automatic mode. The signal meter deserves some extra praise:
Similar to the numerical displays on the PL-880/990 or my D-808, it comes with a signal indicator in the unit of “dBµv/EMF”, indicating 0-90 (or 100? 95?) dBµv/EMF with marks every 10 units from 10 to 90. But this is a bar stretching over the entire width of the display and it has a really fine resolution (13 pixels per division, together at least 120 positions!) and that makes it not only quite a joy to watch but also quite useful for a change!
I find it refreshing to see some “analog-ish” meter on a small portable radio, giving me a very fine and immediate indication of the signal and – particularly valuable for me – the noise floor in a satisfyingly high resolution, albeit with the limitation of not showing anything below 0 dBµv/EMF, which is -113dBm or roughly S2. However, also owed to the radio’s high sensitivity with just the whip, I can not only see the atmospheric noise on 20m during daytime on the beach, I can also tell intuitively if it’s bad or not so bad and notice the drop when the band is about to close, because I have already 13 different positions between “no indication” and “10” where other portables have 5 positions for the entire level range or aforementioned numerical displays, which are abstract and slow due to the needed long averaging/integration time to provide readable numbers.
Converting dBµv/EMF into more customary units is way beyond my math skills but thanks to multiple converter pages I can hopefully help:
The thin line above the meter indicates the “sensitivity” (RF gain) setting and it works in reverse from right to left. This looks like a meaningful arrangement in that the signal meter indication doesn’t change with the gain setting (it still indicates the input signal even when sensitivity is turned all the way down!), so the meter may roughly indicate the ballpark for a sensitivity setting that keeps the AGC from riding the signal for most quiet and pleasant listening to some strong stations in SSB.
Despite only having 6 controls and several sub-menus for settings, I think even for less experienced users the operational concept should sink in pretty quickly because it’s quite intuitive or at least not hard to figure out even without the manual. The English manual is short but well-written and a separate download, the radio comes only with a small slip explaining the different power-on modes because it is set to “safe mode” for shipping and doesn’t initially turn on by just hitting the PWR-button.
Basically, the push function of the rotary knob confirms a selection you made with it in one of the menus and gets you back to the frequency display, each of the 4 buttons can be pressed once to reach the first menu level, twice or more to get to the next levels etc. and a new setting becomes effective when you reach the end of the menu chain, if you don’t just push the big knob.
That being said, while the radio is pretty simple to use, having the only rotary knob controlling any variable parameter on the radio comes with a few ergonomical drawbacks and since that knob also dubs as pushbutton, there’s some opportunity to end up on a slightly different frequency than before after adjustments in the menus – the encoder is quite sensitive with many (100?) pulses per revolution and no indents.
There are 32 memories that store frequency, mode and sensitivity (!), but not bandwidth (which is saved per mode) or step width (which is memorized globally for all modes). Selecting, saving and loading memories is as straightforward as it gets but I quite often save a memory by accident instead of loading it, because the “Mem” button that calls up the memory page is also the “Save” button, while the “Vol” button recalls a memory, which is consistent with the operational concept of the radio’s menus but for some reason my internal logic for the memories is wired the other way around. If you pressed the ‘Mem’-button by accident, hitting the ‘Mod’-button gets you out of that menu to return to your currently set frequency.
BTW, the “spy radio” theme of this review wasn’t only inspired by the size and origin of this radio but also the memory slots, which came pre-loaded with band centers etc, and a few pretty odd frequencies (USB), of which some were showing up in logs of number station monitoring sites only. Using memory slots to jump to bands is not the only way to quickly reach another band though: keeping the knob pushed while turning is putting this into a “fast” mode. If you have selected a step width of 1 kHz or more it’s quite easy to jump to a band several MHz away with very few turns of the knob. With 100Hz step width, each encoder pulse is 10 kHz and it’s often only one quick push-and-twist to go from one segment of a band to another.
Doing the first evening walk with it, I immediately appreciated its particular aptitude for that job: It’s not only more sensitive and has better audio (which belongs into the “ergonomics” category because it’s less dreadful to listen to), it also fits in way more pockets than the D-808. Just hold the ‘Vol’-knob for 2 seconds to lock the frequency, then put it knob ahead e.g. into your breast pocket and there may still be room for some other items in it. The radio is so quiet and sensitive that you can even leave the whip partially or even fully collapsed when you’re just listening to strong stations.
Codename Tinnitus: Downsides and quirks
As per usual, this is the place for the reminder that the perfect radio does not exist, no matter how much money you are willing to throw at it, and the cute little squirrel is no exception.
– The radio is showing a considerable number of birdies across the entire coverage range, something between 1 and 4 noticeable ones per MHz, sometimes very faint ones in between. This is usually a huge showstopper for some people, including me. But then again, birdies are a fairly common thing among all the hyper-sensitive portables and entry-level SDRs and of course they are only an issue if they happen to be on a frequency you want to listen to, in a mode that makes the birdie obvious and it all depends on how likely that is in your personal usage pattern. Even more, some disappear if I connect an external antenna, some only exist if I disconnect any antenna (so that turned out to be a wrong way of assessing how many birdies it really has) and only few of the birdies are having a considerable signal, most of them can only be heard quite faintly in SSB and some are spurs apparently coming out of the mixer so their “relative bandwidth” is only a few Hz, they wander off when you tune the radio a few Hz up or down. Being more of a ham band than a broadcast program SWL, the only (for me) really disrupting birdie I found so far is on 14,175 kHz. Weighing in the considerable strengths and qualities of this radio I concluded that I’m willing to live with that where I have to. Believe me, nobody is more surprised about that last sentence than me!
– In a somewhat related matter, the manual states that the display can cause some noise (unfortunately none of the birdies are created by the display), so the display can be turned off by holding the ‘Mod’-key for a while. However I never noticed any noise that would disappear by turning off the display (and I did that a lot) until I tried to operate the radio in the car with the doors closed and the whip not stuck out of the window. Apparently, within that closed Faraday cage the display noise was reflected back onto the antenna and some hash was audible until the display was turned off. Then on my first walk with the Belka I heard it again – it turned out that putting the radio in one of my jacket’s breast pockets with the display pointing towards my body caused that reflection again – I just turned the radio by 180° so the display faced away from me and that solved the problem. Not really an issue, but something to keep in mind.
– Another observation is some slight loss of sensitivity on 17m. I’m not entirely sure that this is common to all Belka DSP but a Russian Youtube video comparing it with an FT-817 (on some wire antenna in the woods) seems to indicate the same – 18 MHz was the only band where the Belka couldn’t fully keep up with the 817 in that video, and in my tests the 17m ham and 16m broadcast bands were the ranges where it was only as sensitive as the other radios, which admittedly is a pretty subtle difference.
– I know that the soldered-in battery will likely be perceived as a downside by anyone who’s not fond of opening the radio and soldering in a replacement in an unknown and very variable number of years. But such a small radio with that kind of battery capacity just wouldn’t be possible with AA or AAA batteries. If you want to maximize the (easily obtainable cellphone type) LiPo battery lifetime, try to avoid charging it to more than 80%, particularly if you want to stow it away. Only charge it fully when you really need the full capacity and also avoid discharging it below 20% without need. The remaining 60% capacity should amount to ~10-14 hours endurance, which is still a lot of SWLing. The Belka can be recharged on any USB port and even the cheapest powerbank from the $1-store will recharge it at least once.
– Another thing I don’t mind personally but that has triggered criticism about other radios was their bright display backlight and the Belka is such a little reading lamp too, which also serves me well as a safety light when I do my walks in the dark so I won’t be run over by a cyclist.
– The volume control doesn’t turn the audio down to zero, only the sensitivity control can reduce the volume further but that’s just an observation, you don’t turn this radio on to hear nothing. 🙂 There is also a little hiss on the output (not half as bad as on the D-808 though) but that can be easily mitigated by simply using some phones with at least 32 ohms upwards. Most cheap earphones fit that bill, but my old-as-dirt Sony earphones have only 16 ohms and made that hiss obvious enough for me to notice. Without FM band on this radio, you’ll not be running into a listening scenario (classical music, jazz ballads or drama on a really strong FM station) where low impedance headphones or hiss could become a problem though.
– Lastly neither a quirk nor a complaint, but a reminder that this radio is specified to work from 3.5 through 30 MHz: Even with the short whip, most things you will receive below 3 MHz are images of stations above 3 MHz. Of course receiving Shannon VOLMET on 3413 kHz USB is not a problem yet but the lower you go, the more odd things start to show up, for example the Shannon and RAF VOLMETs around ~1.8 MHz in LSB (images from 5.5 MHz). Maybe with sufficient external preselection it will “have” 160m but otherwise take it as if it just doesn’t and it was never advertised as such. I did manage to hear my favorite funny British oldtimer ragchewing net on 1933 kHz though.
Now after all the boring stuff, here’s the radio in action – a compilation of some highlights received the evening I tried the Belka with the pre-amplified 60ft loop-on-ground. I could log some pretty interesting (particularly from a European perspective) stations again, despite the poor condx (SFI=69-70, A+Kpi=normal) we had on all the days/nights during the test, even though the ionosphere was slightly more excited that night, just like me when I picked up some rather unexpected callsigns:
BTW, a LOG is a great outdoor DX companion for the Belka: The antenna can be packed small and put down quickly with the least imaginable amount of hassle (dropping stuff on the ground in an educated way), the receiver is just another tiny box and all can still be brought to a place in your coat pockets. Due to its bidirectional pattern and reduced susceptibility to QRN it likely beats any wire you’d have to hurl up a tree, particularly when there’s no tree around.
The spy who…uh…spy radio I love…umm… summary and verdict:
I’m aware that this review may make the radios I compared the Belka with look bad, which they aren’t. So please don’t get that all wrong, I love my Chinese DSP portables, they’re doing a great job, some of them are very versatile and beat the Belka hands down on any other band than shortwave. But they also come with some common quirks and idiosyncrasies particularly on SSB, sometimes showing their low price…or a conflict with their not so low price here and there.
The Belka DSP on the other hand is a completely different animal (in this case, a squirrel) in terms of ingenuity, architecture, dimensions and likely also target audience – yes, it’s a portable and it’s not perfect either but that’s already the end of the similarities: It’s not a multi-band radio, it won’t wake you up in the morning so it’s not a travel radio by common (OK, by Thomas’ definition), it doesn’t even have a speaker and all it does is shortwave… but that’s what it’s really doing like a big one! It behaves and sounds refined like a regular modern ham radio receiver and generally matches that kind of performance. Its big strength is SSB and CW, but the great stability and precision making these modes so good is beneficial for broadcast listeners as well.
It had no trouble to best my D-808 in the “SWL walkman” role by several orders of magnitude in terms of both size and sensitivity and to my surprise it had no trouble beating my S-8800’s great sensitivity on the whip either, while not showing any of the weaknesses of said radios, except for the birdies. Also, its frontend can take bigger antennas. Underestimating what such a little radio could do, the Belka DSP exceeded my expectations in all aspects by far.
That’s why I never cared less about the quirks of a radio, including the birdies, which are the only really noteworthy issue to me. The overall sensation of a well-conceived radio with outstanding performance paired with irresistible cuteness is clearly dominating my feelings about this, and that it comes from what seems to be a little mom-and-pop business in Belarus at a very competitive price compared to the Chinese offers is explicitly not part of my technical assessment, but it sure is another plus for the Belka. It can be bought directly from Alex’ shop here for currently ~$120 plus shipping, I bought it for ~160€ including shipping via the Mobimax.bg shop in Bulgaria, which certainly included a markup for the middleman and the convenience of PayPal payment.
If you have a craving for communication receiver performance particularly on SSB/CW but lack the funds or just the space in your pockets for a communication receiver, if you want to have a stunning shortwave performer with you all the time even when your carrying capacity is limited to whatever kind of pants you’re wearing, if you’re doing mini-DXpeditions to escape the QRM and want to keep it light-weight but performant – this might be a radio you shouldn’t let pass. Its size-vs-performance ratio is mind-boggling and even though spy radios may be a bit out of fashion nowadays, it would still excel in covert radio operations, like when your XYL frowns at you packing more radios than pants for a vacation.
Please don’t forget to eat or burn this document after reading.
In response to Paolo’s recent post regarding Internet scams, SWLing Post contributor, 13dka replies:
Sellers should be aware too: the same scammers have various schemes to scam sellers as well, and these fake ads play a role in those too, IIRC one popular variant is that the scammers try to buy your item, and offer the same thing on another platform in a different country, then they give their buyer your bank data to let them pay for your item, which gives them the advantage that they don’t even need a bank account to scam you. At the end the scammers have your item, the other buyer reverses the payment because he didn’t get anything.
Anyway, of course the same type of scams can be found with any article on the various “classifieds” platforms, also including eBay and Amazon’s “Marketplace” – RVs, cars, cellphones, computers, anything rare, collectible and/or vintage, pricey and sometimes even more common and cheaper things.
I noticed a serious wave of fake ads for guitars and other music gear on the German “eBay Kleinanzeigen” platform this year. One day I noticed several offers for vintage Gibson guitars usually sold in the $6,000-$10,000 range, each offered around 2,000, of course with pictures and article descriptions stolen from ended eBay auctions and US shops. It wasn’t only the price that wasn’t right, the descriptions being obviously translated from English was quite a dead giveaway. A few days later I found new offers like this and this went on and on, making me curious how many of those might be published every day.
To understand this properly, you need to consider that these “classifieds” are usually searched for local offers people can pick up personally, particularly with musical instruments that people often want to see, touch and try before buying. If I found that many fake offers just in my state, how many of those might show up in the entire country? In short, the amount of fake ads I found on a random sample basis (its impossible to survey the entire thing) was devastating. Even worse, I found that this extended to much less obvious, relatively low-priced current production instruments, also offered at prices that were only “attractive” or “very fair” and not obviously alarming.
A common denominator with all of these scams is indeed the stolen pictures from ended auctions and shops, and original article descriptions translated. You need a bit of “Google-Fu” to retrieve the origins of those and it takes a bit of common sense to distinguish fake offers and offers where the seller was just too lazy to take pics,. However, digging as deep as I could I found out that this musical instrument scamming goes on for at least 12 years now and there are so obvious similarities in the communication between sellers and buyers and shipping addresses that I think it’s the same scammers doing this successfully for that long time. The authorities are apparently over challenged and powerless due to the international character of the scam. Mind you, I checked only this one area of expertise I have and the result was alarming. The dark figure of scam attempts and actually scammed people might be incredibly high if I extrapolate this to all kinds of items.
If you want to stay on the safe side, just don’t try to buy stuff you can’t pick up yourself (or where the seller tries to avoid this by claiming he’s currently in some other country), don’t fall for surprisingly low prices offered by Amazon Marketplace dealers outside of your own country (like the brand new Icom 7300s offered for 599€ a while ago), on everything eBay/Kijiji/Gumtree/whatever try to check the seller’s reputation thoroughly so you don’t fall for 100% reputation scores gained from selling used baby clothing before the account was hacked and used to sell pricy things. If you have the faintest feeling of doubt, just let the deal pass. If you haven’t thoroughly read up on eBay scams et al, keep buying your stuff at local stores.
Thank you for sharing! All very sound advice. As for performing a little “Google-Fu” to find the source of an image, check out this tutorial on Google reverse image searches. Read the entire article as it describes doing this from tablets, phones and PCs. In addition to asking the seller to photograph something specific and unique on the item (like asking them to tune it to a specific frequency or to write their callsign on a card and include it with the item) I also perform a reverse image search anytime I’m purchasing from someone I don’t know.
Many thanks to SWLing Post contributor, 13dka, who shares the following guest post and review:
Do I really need this radio? A very belated review of the C.Crane CCRadio 2E
Ever since my relapse into radioholism a few years ago, I had a craving for a top-notch medium wave radio. This became even more of an urge when Germany abandoned the AM BC band just like many other European countries, leaving a band full of new opportunities but little left to receive during the day, at least with all the average portables I own. When checking the options, there’s no way around Jay Allen’s website if you want to know what’s best on MW, and I learned how little choices there are on the summit of the “5-star”-radios. Over the years I kept looking for an RF-2200/DR-22 et al but they are few and far between over here, and buying a dusty old radio with an unknown history, likely in need of repairs, restoration and alignment, for an insane premium price (up to 400€!) from a stranger was not exactly a pleasant prospect for me.
The CC Radio 2E and its predecessors, successors and siblings are the only radios in the topmost 5-star bunch that can be bought new and at a reasonable price. Sadly, the best product for the European market is only a 4 1/2 star radio and I realized that I have to buy a radio clearly made for the USA only, and accept the parts that don’t make any sense over here (120V, 10kHz AM spacing only, WX band). The problem: getting one shipped to Germany was rather complicated until Amazon.com made that much easier last year.
AM Broadcast Band
After 2 weeks of gleeful anticipation it finally arrived last month and I rushed to the mall to buy plenty of ‘D’-cells, then to the dike to answer my own, most pressing question: “how much better is a top tier Jay-Allen-5-star radio than my average 3-star radios anyway?”. I wasn’t sure what to expect from the 2E, partly because the videos I could find compared it with other good AM radios, or they didn’t compare it at all and sometimes the radio didn’t even get turned on. Nothing really related to the radios I have, after all they represent a whole bunch of popular radios people currently own with a similar (around average) AM performance, like the Tecsun PL-nnn, Eton Executive Satellit or Field, or ICF-7600, Zenith TO/R-7000 to name a few older types – and I was looking forward to fill that gap!
Spoiler alert: the CCR2E’s sensitivity obviously bests all of my other portables. Duh! It should, because my example of the PL-660 isn’t good on AM at all, the XHDATA D-808 [read my full review here] is a 2-1/2 star radio and the Tecsun S-8800 [read my full review here] is a 3-star radio on the “Jay Allen rating scale”, even though I’d rate my examples of these radios the other way around – my D-808 has a tiny sensitivity edge over my S-8800.
So how much better is it? Here’s a cellphone video letting the radios speak for themselves, alas with plenty of wind noise (sorry, it’s usually windy here at the coast!). Make sure you watch it past the somewhat unspectacular first minute:
I hope you’ll agree that this is pretty impressive, and that’s the kind of results I was hoping for. There’s also a simple way of quantifying how much better it is in numbers: if I tune across the band in the afternoon and note all frequencies that clearly show signs of a station (not counting how well it comes in, just the pure existence of some signal that can be identified as “broadcast station”), the D-808 has 11 frequencies populated, the CCR2E has 25. That’s more than twice as much, the 2E has twice as many stars, sounds about right. Let’s also keep in mind that the XHDATA or the Tecsun represent “average”, “serviceable” or “decent” AM radios that are quite satisfactory for most people, and yet there is apparently a whole world between an average radio and the top of the heap. To be honest, I didn’t expect how dramatic the difference would turn out.
That made me curious how my battered old Grundig Satellit 400 would do, after all it was always a tad better than the other portables I have (Jay Allen might rate it 3-1/2 stars), and MW is the only thing in it that still really works. I decided to buy it the last bunch of batteries of its life and took it to the dike:
Evidently the Grundig is a bit more sensitive than my other average radios but without much benefit. Stations with some appreciable level turn out a bit better but it fails at the same stations as the other radios and the C.Crane unsurprisingly runs circles around the Grundig as well. The first and the last station recorded in this video demonstrate that nicely – my favorite low power benchmark station (1602 kHz) transmitting with 100W from a moored old pirate radio ship was just making it over the noise on the S-8800 in the previous video. The Satellit picks it up OK but with more noise. The last station is the BBC transmitter in Redmoss (Aberdeen, Scotland), which is pretty crystal clear on the CCR2E while the Satellit has only little remnants of modulation and the D-808 is at least on par with the Satellit there. That station pretty much didn’t exist on the S-8800 in the previous video either and I wish I’d know why this example turns out so extreme, why the 2E and that station like each other so much.
The closest stations in these videos are in The Netherlands, 150+ miles away and have only 100W, most of the UK stations are between 350 and 420 miles away (most of them not very powerful either), Scottish stations are around 500 miles from here and the Redmoss 2kW BBC transmitter on 1449 kHz with its beautiful signal is 490 miles. Given that this is daytime groundwave reception with no help from an external antenna, I consider this pretty darn impressive. But keep in mind that a part of the impressive results is due to the low noise location and the conductive North Sea water being only 50m from my position behind the dike, then stretching most, sometimes all of the distance between the radio and the transmitters, which definitely helps groundwave propagation a lot.
To put the benefit in some more practical metrics – my average radios pick up at most 3-4 stations in a halfway sufficient quality for continuous listening during the day, the 2E makes that at least 8-10 stations. While sensitivity is playing a somewhat lesser role at night, it’s pure fun to browse the band and discover stations that didn’t stick out of the noise enough in the past. It is undeniably an exceptionally sensitive and stunning AM receiver.
Selectivity, overloading resilience
The 2E has a wisely chosen single bandwidth more on the narrow side. Given the intended purpose of this radio, I think one can live very well with the “one size fits all” setting and the intelligibility remains excellent. At night when the band is getting crowded even over here, the 2E has absolutely no trouble separating the channels.
Other reviews mentioned that its dynamic range may not be sufficient to cope with local blowtorches and I’m sure that this is true. I don’t have local blowtorches, but I tried coupling wire fences between 200 and 1000m (600-3,000′) to the loopstick antenna, and it could cope with those arrangements better than the S-8800 and the D-808: at night, both of the latter present some roar between the stations on the lower end of the band (which is of course mostly intermodulation products). Both radios then need some looser coupling from the coupling coil, on the the S-8800 I can also lose the preamp stage (“local” switch) to mitigate this, the D-808 can’t do that and has the most problems with images, for example clearly discernible images from the top of the NDB band just 100 kHz lower in the same band.
The CCR2E stays pretty quiet on the few frequencies the fence antennas leave unpopulated. In other words, its frontend may not be as good as the one in some vintage receivers, but it still takes more of a beating than e.g. the Tecsun S-8800 with its improved (over the PL-880) frontend.
Lacking really strong signals, I can’t comment much on all of the AGC action but I too think it doesn’t pull up weak signals as much as other radios. That makes the 2E appear even less noisy between stations, but being desperate to catch some transatlantic DX before sunrise (yawn!) despite the season being over, I found myself a few times with the volume knob turned up all the way to the right stop on some quiet channels, while the band was filled elsewhere with considerable signals from that 3,000′ fence. The time constants are more on the slow-ish side, thunderstorm impulses make the signal dive away for half a second and it seems to struggle with weaker stations that come with a fast fading. SDRs with fully adjustable AGC characteristics sure have spoiled me.
FM Broadcast Band
FM sensitivity is excellent in all of the portables I have (S-8800, D-808, PL-660) and the CCR2E can match their performance, there are generally only very little differences between all those. As mentioned in my S-8800 review, I found its sensitivity can’t fully match the PL-660 and the D-808, even though it employs the same DSP chip type as the D-808. I briefly compared the CCR2E with the S-8800 on FM (simply because both are big radios, and I guess I wanted the 2E to win this too).
Comparing portables on FM is a bit of hit and miss though – you need to find borderline weak stations to begin with, and then you have to make sure each radio’s whip antenna is adjusted for maximum signal, and you need to put one radio at a time on the table, because otherwise the whip antennas can interact with each other and make it hard to find the optimal antenna postion/tilt/rotation. When I tried the CCR2E at the dike, a complete lack of tropo conditions limited the number of test stations a lot, and the remaining stations were not really weak enough to find a clear winner among the two. Both radios were on par most times, sometimes it felt like once the 2E gets a bit of signal it will present it a tad less noisy than the S-8800.
But then a very borderline faint Dutch station on 88.1 MHz made it over the North Sea with much noise on the S-8800. No matter what I tried with the 2E (antenna gymnastics, raising, repositioning, lifting up and tilting the whole radio and swearing at it), it picked up nothing at all. That looked much like the 2E is actually less sensitive than I thought, but as it turned out later there is a much happier explanation for this:
Since the day I got it, I had the impression that the 2E has a narrower FM filter than my other radios. Tuning 50 kHz next to a weak station makes it almost disappear and 200 kHz off a local station gave me much hope for letting a weaker station pass unharmed. Now when I checked the station listings for my Dutch mystery station on 88.1 MHz it turned out to be very unlikely that I received the station listed there for 88.1 – “Radio 10” in Hilversum has only 3 kW and is a bit too far away, without any tropo help anyway. What’s way more likely is that I actually heard the much closer 60 kW “NPO 2” transmitter in Smilde on 88.0, that is, its upper sideband on 88.1. To understand this you need to know that Dutch (and AFAIK French) FM stations like to plow their channels with some rather hefty FM deviation unknown in Germany. The wider filter of the S-8800 picked up so much of that extra-wide deviation that I could identify the language. I could not hear the station on its actual frequency 88.0 MHz either, because a much stronger local station on 87.9 was whacking it.
The CCR2E just didn’t pick up any of the surplus deviation from 100 kHz lower, which is a quite striking evidence for a narrower filter (<200kHz), and this might also explain why it appears more sensitive when it picks up some weak station – a narrower filter means a better SNR on FM. I did not read Jay Allen’s “FM shootout” (where the 2E is the topmost radio as well) before tried the radio and I’m not sure yet if I’d put it above all other radios too. But it’s very safe to say that the 2E is likely about as sensitive as all of the contenders in the very crowded 5-star class in the “FM shootout” and its selectivity might be giving it an advantage over other radios. Too bad such a good performer on such a short antenna doesn’t have an external FM antenna input and RD(B)S.
2 Meter – VHF and Weather Band, SSI
Short story, there is no NOAA WX band in Europe, and my local 2m repeaters don’t even seem to transmit their ID every 10 minutes anymore like they were supposed to do in ye olde days, maybe they’re gone. Analog VHF ham radio has ceased to exist around here and if we’d have some catastrophic event, all a 2m receiver could do to help you is emitting some soothing white noise.
I will use this section to talk about the signal strength indicator on the CCR2E instead. With 12 discrete bars it has a better resolution than e.g. average portables, which often try to look like they had even more bars but actually have 5 sections of 4-bar groups, in other words they just have 5 real bars. The better resolution of the 2E is certainly helpful, for example when you pair it up with some kind of tuned external antenna – but it seems to indicate levels with some delayed response and that ruins it a bit.
The 2E has a quite satisfying bass and treble response for music listening on FM (if you turn up the controls). It has the biggest speaker of all of my portables and creates some audio that rather reminds me of a small home stereo than a portable radio. However it doesn’t have the power to really do “loud” and the bass may run out of breath and distort pretty soon on some music styles.
For a few days I couldn’t quite put my finger on why it didn’t put that much of a smile in my face like the S-8800 or my old Satellit 400 do, and I remembered the quite controversial ratings of the 2E’s sound I had read. I felt that it doesn’t have that special “big portable” in-your-face bass sound my other big radios have, a sound that was burned into my eardrums by all the big Grundigs and Nordmendes I had since when I was a teenager.
The answer might be quite simple though: the 2E has a much wider frequency response than those radios, it actually reaches down lower and the treble range is also extended. What we (OK, at least I) perceive as that “warm” and “big” sound in those old portables is actually “pseudo-bass”. Pseudo-bass is a psychoacoustic effect that tricks our brain to perceive louder and fuller bass when actually only the first harmonics (typically one octave higher) of bass instruments are heard, for example because the speaker is too small to actually render the fundamentals, with the “bass” tone control boosting the harmonics instead. The 2E sounds more like a small 2-way hi-fi speaker and tries to do “real bass” rather than pseudo-bass, which is much more demanding in many ways. Pseudo-bass is also much less depending on automatic loudness correction at low volumes, so the 2E seems to lack bass at “bedroom” volumes sometimes, compared to the Tecsun or the Grundig. Though once a station plays the right music and the 2E is turned up a bit, it’s getting quite obvious that it can sound even bigger than those other radios.
On AM the CCR2E can even produce too much bass that needs to be dialed back: like talk radio dominates the US AM band, its EU pendant is still reigned by pop/rock stations (usually employing lots of signal processing for extra-fat sound). On those stations, the CCR2E can be bassy to a degree where the bass is almost sounding detached from the rest of the signal, as if it’s coming from a different, stronger station. It’s a more boomy, “wet” or maybe a hint less “musical” bass sound, this is rather a wordy description of impressions and not a complaint though. It just doesn’t massage my auditory cortex the same way the other radios do, which is of course a matter of taste and “getting used to it”.
The tone controls are modern and efficient like the ones you find on the S-8800 – compared to my old Satellit, they have a steeper roll-off at well-chosen cutoff frequencies so you can eliminate just the hissy top end in the treble range or remove all that rumble below 200Hz, leaving the midrange in between untouched. On the positive end of the knob range, they just add deep bass and a nice clarity on the top, as if the 2E had a tweeter.
So it does sound great and I can see now why the successor radio, the C.Crane Radio 3 got upgraded with Bluetooth. But the 2E is a great powered speaker as well, it has an AUX input radio nuts can use to boost the audio of an SDR connected to a laptop or a small SW portable to the same level of fidelity. The manual claims that the 2E has a battery endurance of 250 hours, which would mean it should serve all day for at least a whole week as an awesome powered speaker for your other radios out in the woods, and it even might become the best speaker (with very useful tone controls!) in your home shack. This works so well that I deem this a serious (and perhaps often unconsidered) asset.
One thing I don’t like a bit is a strange scratchy narrowband distortion that seems to come up within a certain level range. It’s independent from the station, the frequency or the noise on it (and not to be confused with multipath distortion), it’s showing up across the band and is solely depending on the input signal as it seems. It doesn’t affect stronger signals (so there shouldn’t be anything overloading) but if a station hits a certain low signal level it’s quite permanent and also quite disturbing, if there’s fading the noise will come and go when it passes through that level range. The only way to mitigate that prickly “frying pan” sound is turning the treble knob all the way down. I don’t know if that’s a bad case of demodulator distortion or some AGC related malfunction and for some reason beyond my understanding (strong out-of-band signals playing a role maybe?) this does not always happen. Still a bit of a fly in the ointment.
A rather harmless little quirk I (among others) found is happening when I recall preset stations on AM: under unknown circumstances the 2E will not tune the antenna properly so I need to change the frequency and tune back to get full signal. I assume that the coil tuner setting is saved with the preset, and when the environment of the loopstick changes (like when you saved the preset at a different place), the saved tuner setting does not fit anymore. Retuning, then saving the preset again should fix that.
Rather fast fading can have a similar effect on the tuning process, if I tune and retune to such a station, I may end up with different signal meter readings and volume every time – it seems that the integration time window used to automatically tune to peak signal can be too short in relation to the fading speed and that may lead to a less than optimal match of the coil. Admittedly, tuning to peak signal on fickle stations like that is just as hard for a human being. Since the tuner seems to rely much on locking onto a carrier, offset tuning (e.g. like DXers often do to optimize reception of a station with a strong channel neighbor) may not work as well as with regular receivers, signal and volume can drop quite dramatically when tuning 1 kHz to the side, and it sounds like this is bad for the SNR too.
My example of the 2E has a “birdie” between 99.7 and 100.0 MHz, which luckily doesn’t make any noise on FM. It doesn’t seem to harm reception much (if at all), I can still get a rather weak Danish station on 99.9 MHz but I can’t tell what effect it has on stations on the other affected frequencies.
External AM antennas
This is not a quirk, it’s rather a design decision I deem not working anymore in many (if not most) of today’s homes, or simply an oversight: the CCR2E is yet another radio that has screw terminals for an external AM antenna but no means to take the internal loopstick out of the circuit. This is not a problem as long you are using radio and antenna in an electrically quiet and interference-free environment, in which you may not even need an external antenna because the CCR2E is such a good performer. If you want to use one anyway, the 2E will benefit only from antennas with considerable gain, very lossy designs that trade gain for low noise and high SNR (like BOG, LOG, EWE…) may not even leave a clue of their existence on the 2E.
If you live in the city, in an apartment building, a crowded neighborhood or just a modern home and want to let your family use computers, appliances, switching-type wall warts and so on while you listen to distant stations, an external antenna may be the only way to enjoy the radio’s performance but even an antenna with lots of gain will not help getting rid of the hash and noise of the digital world. It may increase the signal a bit to improve the SNR, but the noise level will stay the same because it’s being picked up and added back by the internal loopstick. I think that any ambitious modern receiver should take the ever-worsening noise situation into consideration. Paradoxically, back in the 50s and 60s local noise was much less of an issue but a lot of radios had switchable loopsticks. They were all tabletops though and to be fair, I know only one portable radio with that feature (and that’s a scanner which sucks on AM).
First off, using this radio is generally very straightforward. The only thing I needed to learn from the manual was how to keep the frequency on display, which is only possible with newer versions of the firmware. My radio was manufactured in January 2018 and it has this option, plus an updated version of the printed manual, now describing that (and the antenna calibration) procedure. (Just hold the “Clock” button, then immediately hit the ‘1’ memory button on top. The radio should emit a beep and from then on the display will show the frequency.)
You may want to think twice about buying the “Titanium” version of the radio. The product photos on Amazon were showing the radio with somewhat different and darker hues between grey and champaign, so I spontaneously decided to not buy yet another black radio. What I pulled out of the box was blindingly silvery and yelling “plastic” though, so don’t let any pics fool you – “Titanium” is just a fancy name for the same old standard “light grey-ish/silvery plastic” seen on a billion products from the Far East in the past 50 years. A matter of taste of course.
If it wasn’t obvious to everyone already – this bulky radio is more like a “portable tabletop”, it’s only little more “portable” than a big old Transoceanic or Grundig Satellit with a broken handle. New radios get lighter and lighter even when they get big (like the S-8800), the CCR2E brings gravity back into the game, so on the plus side it will stay put on the table when you push a button, or when there’s an earthquake.
While it does radiate some quality feel (nothing is loose, wobbly or rattling), the tuning knob is the exception: it has a tiny bit of play and it feels and sounds like it had a former life as a hairspray can cap. The stepping/rasterization of the encoder resonates in that cap and if you want to tune to a distant frequency on the dial you just need to say “rien ne vas plus” before you turn the knob to create a great acoustic impression of a roulette table. On the other hand, the solid steps of the encoder causing that sound are very precise and the sound helps me counting the 9 steps I need for hitting the next channel in the European AM BC band. Some reviews also complained about the flimsy FM whip and I used to think the D-808’s whip is flimsy, but this one has a top segment with a diameter of one millimeter, the antenna is the shortest of all my radios and looks exactly like the whips I’ve seen on most of the cheapest (<$20) radios I came across. But that doesn’t affect its function of course – that is, while it lasts.
Now that’s even more a matter of taste, but I just can’t leave the design uncommented. I’m still undecided whether it looks more like a hi-tech humidifier than a radio or not, luckily it says “Radio” in red letters on the speaker grille but still… I don’t know if it’s the complete lack of “retro style” and its sober, “senior-friendly” approach or just the color – whichever way I look at it, it ain’t the most handsome radio of the pack. I think I can get over it, provided I never watch any of Thomas’ videos featuring his gorgeous RF-2200s again. So all it can do to win my heart is working well, that is, very, very well. Let’s see if it succeeded:
The C.Crane CC Radio 2E is an extraordinarily sensitive radio on AM and certainly among the best on FM. It puts some effort in picking up AM stations that most other portables won’t and that’s what it really does as advertised. Like any other radio (so that’s not Bob Crane’s fault like some disappointed Amazon reviews allude), it will not be able to do that in noisy, interference-infested environments and not even an external antenna might help much with that, because the internal loopstick stays on. In an electrically quiet environment though, it’s nothing short of marvelous.
It has a great sound and to my own surprise, I found its qualities as a powered (also long-lasting battery-powered) speaker for other radios a serious asset. It’s simple and easy to use but that also means it lacks all advanced features that would help in difficult, “hardcore DX” reception cases. With its bulky form factor, the built-in power supply, the 4 D-cells, the weight that all brings and the lack of a proper handle, it might not fit into everyone’s understanding of “portable” and its specs are rather meant to cater the needs of American homes. However, importing it to Europe can make sense even with the extra taxes and shipping (which means a 40% markup in Germany), at least for AM radio lovers who want top performance and avoid the problems vintage portables can bring. It’s at any rate a sensible choice if your favorite station is somewhat beyond the range of average radios, if you just want more stations to choose from, or if you enjoy general daytime groundwave DX, all without making an external antenna a necessity.
Of course the CCR2E is not the mythical “perfect radio” either. The muting and automatic loop-tuning when browsing the band isn’t great, it has a few quirks, a flimsy whip antenna and a tuning knob with a cheap feel to it but then again, it’s not an overly expensive radio either and its price/performance ratio is certainly appropriate and attractive. It may not be much to look at but I like it anyway because – among all the all-rounder radios I have – it’s the specialist doing that one thing really well: making AM radio feel like it used to be.
So do I really need this radio? Maybe I don’t, but now that I’ve learned how excellent it really is, I know that I really, really wanted it!
Wow! What a brilliant review! I absolutely love the details you fit into your evaluation and your wit, too (especially that bit about the tuning knob possibly having “a former life as a hairspray can cap”–!). Ha ha!
Nice weather and pics! Hmmm… it wasn’t so obvious to me before but it looks like the Skywave SSB is even smaller than the D-808. Now I’m jealous! ?
I find it pretty amazing is that just a few wavelengths away from the water, the signals seem to be tapering off a bit already, so standing IN the water and holding a portable is certainly getting the absolute best out of the radio. When I moved here (to the coast) I took a portable with a relatively stable station tuned in and drove to my beach listening post with it, then I headed back home right away. It seemed pretty obvious how the proximity to the water gradually improved the signals but of course that was a pretty unscientific test. I should repeat that with an SDR rigged up on the passenger seat and do that a few times in a row.
I’m off now to check how I can get a Skywave SSB to Europe.
It is quite amazing how large bodies of salt water enhance reception! 🙂 Although my home in the mountains has very little RFI, the ground conductivity is poor. Those who live on the coast get much better mileage from their antennas!
Regarding the size of the CC Skywave SSB and XHDATA D-808, based on my measuring tape, the D-808 is about 1.25″ wider, 0.5″ taller and perhaps 0.125″ deeper than the CC Skywave SSB. Here are a few photos:
Not a massive difference in size by any means, but the Skywave SSB is smaller in every dimension. Since I typically do one-bag travel, I always choose the smaller radio. Of course, the D-808 is more affordable than the Skywave SSB and is easier to purchase outside the US.
I don’t know of a C. Crane distributor in Europe. Perhaps Post readers might comment with suggestions?
Many thanks to SWLing Post contributor, 13dka, for the following guest post:
Tecsun S-8800 Review
Looking for a new toy again I recently revisited the Tecsun S-8800, which looked like it could replace both my battered old Grundig Satellit and my Tecsun PL-660. Being in production for a few years now, and with the “birdies” situation ironed out long ago, the S-8800 has gathered much acclaim by now but also a few somewhat contradicting reviews. For example, one review reports that the S-8800 can cope with larger antennas, another one states the exact opposite, one praises the MW performance, another one attests only average sensitivity, and only one mentioned an unpleasant detail I’m going to emphasize on in a bit.
All reviews touted the improved SW performance in AM and SSB though, and that was reason enough to make my own experiences. Testing it turned out to be a bit of an emotional rollercoaster though.
I hope I can share more than only redundant bits of information about the radio, and I’ll skip most of the general information you can read in most other reviews.
Off to the 13dka radio test site at the dike!
13dka’s SWL Happy Place
Like the technically somewhat similar Tecsun PL-880, the S-8800 is a triple conversion receiver and has 2 conventional IF stages, the third IF stage is using a Si4735 DSP chip again, providing the filters and all that jazz.
Tecsun seems to have thrown a lot more parts into it than in previous radios, plus a pretty big ferrite rod (covering 8-9/10th of the radio’s width) with individual LW and MW coils (most of the smaller receivers have only one coil), a 108mm telescopic whip and of course the “gun metal” knobs. Designing a radio with a rather simple front panel and making a remote control an integral part of the operation concept (like it is reality with TVs for a long time) is a charming oddball approach, in a way reviving an utmost luxurious feature of 1930s high-end radios. So let’s cut to the chase and talk performance:
Longwave and Mediumwave
On LW and MW, I first compared the S-8800 with my old Grundig Satellit 400 at home. The old clunker has similar dimensions, a big old speaker bass/treble controls and it was known to have an average sensitivity on the AMBC band in its time, when all the great, now vintage AM performers were still ubiquitous, so that’s rather a “Jay Allen average” than an “average of the mediocre AM radios of this millenium”. I think Jay Allen might rate it 3 stars.
The first station I tuned in was the BBC LW transmitter network on 198kHz and it turned out a tad more noisy on the Satellit. Great! I could also pick up Medi1 and Kalundborg a smidge better than on the Grundig, and in the early evening, out at the beach I was picking up stations on all still populated channels on LW (minus 180kHz where it has one of the remaining birdies). The other new portables I currently own (PL-660, D-808) are far away (PL-660) and far, far, far away (D-808) from that kind of performance.
Unfortunately that good impression vanishes gradually when leaving the long wave for the NDB band (still good) and finally medium wave. Before I left the house to test the radios on the electrically quiet beach again, I was checking out one of my favorite border case stations (low power station from The Netherlands on 1602kHz, whatever their name is this week) and that made very clear already that the S-8800 can’t hold a candle to the Satellit, at least not on the top end of the MW band. Despite all the noise indoors, on the Satellit I could easily recognize the song being played while the S-8800 didn’t pick up anything at all.
On the beach it turned out that – despite the ferrite rod being twice the size – I find it only marginally better than the PL-660, and not close enough to the little XHDATA D-808 (if you’ve read my D-808 review you already know that this little radio is almost on par with the Grundig on MW):
Of course I have read Thomas’ assessment of the AM performance so I was prepared to be underwhelmed. But at least you can connect some high gain MW antenna to make up for the missing sensitivity and be happy again, or can you?
A not so nice surprise
The unpleasant detail I mentioned before is: the Int/Ext Antenna switch does not turn off the internal ferrite bar antenna. Jay Allen mentioned it in his review, it was the only review with that detail and unfortunately I overlooked it. How does that matter?
The main issue is this: if you’re (like me) forced to use outdoor antennas to escape high indoor noise levels, the internal loopstick just won’t let you. The external antenna will just increase the SNR a bit when the station is strong enough anyway. Even in a low noise environment, the internal loopstick will needlessly add noise to the signal received from a high-performance active loop or FSL antenna.
That also explains a paragraph in Thomas’ S-8800 review:
“I also hooked up the S-8800 to my large horizontal loop antenna. This certainly did improve MW reception, but not as dramatically as I hoped. Additionally, it seemed to be very sensitive to RFI in my shack even when hooked up to the external antenna.”
There’s more external antenna idiosyncrasy: only the BNC jack is wired to the “Ext” position of the antenna switch, the “hot” (red) Hi-Z terminal is active when the switch is in the “Int”-position, it just seems to save you an alligator clip on the whip.
The dedicated “AM antenna” terminal was in part what sold the S-8800 to me. The label made me assume this would be specifically wired to the AM circuit but as it turns out it’s just a generic high impedance input and I really didn’t anticipate that the internal loopstick remains always active (or in case of the Hi-Z terminals, the retracted whip). Yes, technically you can connect an external antenna for MW, practically…YMMV.
To conclude this section, the final outcome of this antenna connector issue plus the not so brilliant MW sensitivity was that not even my active ML-200 loop (connected to the BNC-jack) could improve reception on 1602kHz enough to make the S-8800 get at least a bit into the ballpark of the Grundig with its loopstick antenna. The currently mounted small 80cm rigid loop on the ML-200 just couldn’t produce enough signal to lift the station over the noise that much.
As the other reviews reported already, Tecsun has obviously worked on the AGC issues their former products had. I can confirm this so far, the AGC does not show the distorted onset of leveling anymore – unless the signal is very strong. But the leveling happens much faster than e.g. on the PL-880 so the remaining blasts of distortion are quite short:
A more relaxed AGC release time would save us most of those too. I noticed AGC pumping effects from strong signals in the spectrum neighborhood only with a big antenna connected. But unfortunately there is more…
Stuff you have to live with:
In his great review, Thomas mentioned the auto mute sometimes interfering with reception. I noticed this too (with all bandwidths on SSB) and I credited this to very low noise figures. When the bandwidth is narrow (=less noise) or if you have a very low noise floor anyway like when tuning through 25-30MHz, the receiver gets muted over the entire chunk of spectrum, just to intermittently and pretty suddenly pass the noise again. Sounds like a broken antenna cable and has some potential to confuse people:
Too bad that setting auto mute to ’00’ doesn’t actually turn it off in SSB mode so there’s likely no remedy for that.
On my example, there is absolutely no difference between the 3kHz and 4kHz SSB filters. A working 4kHz filter would have been a good choice for ECSS reception.
Another remaining quirk at least on my specimen of the S-8800 is a slight FM modulation of an oscillator in SSB, particularly with strong signals. You can hear it best if you create a heterodyne or listen to CW, the tone sounds a bit hoarse, so do voices and I’m not sure whether or not this could affect narrow-bandwidth digimiode decoding. The front panel (namely the bandwidth knob area) is quite susceptible for “hand capacity”, the frequency varies a bit when you move your hand in front of the S-8800. This is not uncommon with portables of course, but my D-808 for example has its “Theremin playing area” on the back of the radio.
In this clip you can hear both the “hoarse” modulation and my hand waving to you.
This leads me to calibration and frequency drift. The S-8800 can be calibrated on SSB (see the “Hidden features” section below), however this turned out to be a (too) fast moving target. I don’t know if it’s the VFO or the BFO but it is so temperature-dependent that 6°C temperature difference equates to a quite substantial (for SSB) drift of 150Hz. Whatever oscillator it is, it seems to lack any temperature compensation measures, with all the implications that may have on relaxed SSB listening, digimode decoding and ECSS reception when the temperature isn’t quite stable where you want to use it. After calibrating it, it’s often slightly off again within the same minute. My cheap little D-808 won’t drift even when I take it from an overheated apartment into a -5°C cold winter storm.
The good stuff
Now to the fun part! When I compared the SSB performance of the S-8800 with my PL-660 the first time, I found them very close for some reason. I could find only one weak station that came in noticeably better on the S-8800 and while I was happy that it wasn’t worse than the PL-660 I was also a bit disappointed.
Timeline: 0:00: PL-660, 0:10: S-8800 receiving the “Gander Radio” VOLMET.
Then I repeated the test a few days later, this time a bit more into the evening and the outcome was very, very different. The S-8800 won every single weak signal comparison with ease and sometimes in a way that made me think my PL-660 must be broken.
But then I could help the PL getting a lot closer by simply holding it in my hand, the difference was that I had placed the PL-660 differently so I could record both radios easier. The factor I forgot to put in the equation was that the S-8800 is absolutely not depending on anyone holding it to give it some counterpoise – that and the long whip is certainly a part of its advantage, and the receivers would be much closer when used with the same external antenna. With the radios just standing there tho (and that’s what most people will do with their radio instead of holding it in their hand), the difference is remarkable nonetheless and I also learned that you should always look and listen twice when testing radios!
When I repeated the test yet again but granted the PL-660/D-808 the litte bit of counterpoise they seem to need (I let them rest on the car door instead of holding them), the results were not that unequivocal anymore. However, the receivers were 50% on par, the S-8800 was clearly better the other 50% and overall the other two receivers could not score a single point for them. I think that shows that the S-8800 really is a hair or three better. Beyond the increased sensitivity and minus the frequency drift, SSB reception feels more mature, the the S-8800 behaves more like a regular communications receiver now and the big speaker is a big plus. Of course that means there should be also an improved reception of…
I know that the S-8800 has inherited the “Enjoy broadcasting” and “BCL RECEIVER” lettering from the cheap S350, but after stepping the PL-660 and the S-8800 through all shortwave broadcast bands, I felt that’s exactly hat it was made for, and it shows!
There is no doubt that a big speaker can create the illusion of better reception, but I think I don’t fall for that easily and rather listen to the background noise and how intelligible the “content” is. While the comparison with the PL-660 often ended up in a tie when I subtracted the impact of the speaker in my mind, there were indeed some stations where the S-8800 had remarkably less noise than the PL-660. But of course the big speaker is giving the S-8800 a permanent edge on all reception cases, and it’s a real joy to listen! Combined with lower noise and a generally more stable signal (through better AGC) this made quite a difference between the two.
Bottom line is that when listening to shortwave broadcasts, the S-8800 gives you the warm and lush sound of yesterday’s famous receivers while it technically delivers the best performance of all Tecsun portables so far. If you fancy music programs on shortwave and if you don’t mind the price for the luxury and performance, you’ll enjoy this radio a lot.
Short story: my specimen of the S-8800 lacks the very good FM band sensitivity of the PL-660 or the XHDATA D-808. While the latter radios present my favorite marginal case station 100km away fairly with some noise at sea level, the S-8800 just doesn’t receive that station at all, no matter how I position the whip. It’s not exactly worlds between them but considering that (assumedly) most of the FM receiver is in the Si4735 chip that it shares with a couple of great FM performers from the same company, this is a bit surprising.
Signal handling capabilities
The S-8800 is said to have a pretty robust frontend, which I found true but I want to put that a bit into relation. My “lonely beach/dike listening post” sports 2 abandoned steel flag poles of 6 and 8m height. They can serve as support for wire antennas, or easily be used as an antenna themselves by inductively coupling them to the receiver – IOW by winding a wire 2-4 times around the pole (you could use the Eiffel tower as an antenna this way) and connecting the other end to the radio.
For some reason this contraption produces quite massive output voltages, but I could always use it for a quick and thorough (and due to the location QRM-free!) reception improvement with my PL-660 anyway. Why?
The PL-660/880 have a 3-position (DX, Normal, Local) switch. I think it turns off the input preamp in the “Normal” postion and adds a simple attenuator circuit in the “Local” setting. The latter is sufficient to tame the output of all sorts of antennas (including the flag pole) enough to make my PL-660 work just fine with that on all bands.
The S-8800’s sensitivity switch on the other hand has only 2 positions and telling from the results it really only turns off the preamp. Now it actually acts up much less on the flag pole than the PL-660 in its comparable “DX” and “Normal” positions, so obviously Tecsun has put some effort into making the frontend more robust indeed. But it seems they thought “that should do, let’s ditch the 3rd (attenuator) position and save 3 resistors” and that left me with many (but tolerable) images across the entire shortwave above 3 MHz, and a heavily image-infested 160m band. BTW, a few soft images from (I guess) 49/41m blowtorches could be heard around 29MHz with only the whip.
A word on the audio
I believe that the “legendary” status of the Grundig and Zenith lines of world band receivers is partly owed to their big sound. They had their music loving and program listening audience in mind, and Tecsun’s choice of casing, big speaker, the bass and treble controls are certainly taking the same line.
Compared to my Satellit 400 (80s model, but still has much of that “legendary” sound), the Tecsun sounds a bit more boomy in the lower mids while having a less super-deep bass response than the Grundig, which also sounds more neutral. Besides these very unimportant distinctions, the S-8800 does sound big and that also helps reception – lacking low mid/bass content can impair intelligibility as well, and it causes more fatique on long DXing sessions.
The bass/treble shelving EQ is certainly more sophisticated than the Grundig’s, it has quite sharp cutoffs at very sensibly chosen frequencies, so turning the knobs down will leave the main chunk of the mid range completely unaffected and just helps removing rumble or the 5kHz beat frequency from a band neighbor, or add some nice hifi-highs and beefy low end when you turn them all the way up. In other words you can continuously blend the speaker sound from perfect “voice communications” style to “dad’s big old radio”.
Of course the S-8800 has some unofficial “power off” and “power on” extra functions assigned to the number keypad on the remote (they all work by pressing and holding a number key for up to 10 seconds). Some are identical to the PL-880, some are different:
0.) I found calibrating the S-8800 on SSB works with the same method used on the PL-880: Tune to a station with a known frequency, switch to USB or LSB and use the fine tuning knob to tune for best audio/music playback. An alternative way of doing this is downloading a free spectrum analyzer app for your smartphone (“SpecScope”), tuning the radio 1kHz off frequency so you get a nice heterodyne tone on USB or LSB, then using the fine tuning knob to tune the tone to hit exactly the 1kHz mark on the analyzer display. Your last 2 (Hz) frequency digits will now show an offset frequency.
1.) Then press and hold the ‘0’ button until a ’00’ appears in the top right corner of the display and the last 2 digits of the frequency readout start flashing. Release the button and quickly use the fine tuning knob to reset the last frequency digits to ’00’ (the number on the top right corner should be changing while doing that), then immediately hold the ‘0’ key again to confirm – tadaa, the offset should be gone while the last 2 frequency digits show ’00’ now. This all needs to happen pretty quickly and with the right timing, so it may take a few attempts to get it right.
2.) With the radio off, button ‘2’ turns the LW band on/off.
3.) Press and hold the ‘3’ button while the radio is off to toggle between permanent and “intelligent” display illumination.
4.) When the radio is turned on, this button enables access to the extra functions of the number 6 and number 9 keys. The display will read “On” when you perform this the first time, doing it again will turn it off again.
5.) Radio on, set to FM band: this toggles between 75 (US) and 50 (anywhere else) microseconds deemphasis on FM.
6.) Radio on: When enabled using the ‘4’-button as described before, holding the ‘6’ will toggle the (annoying) dynamic bandwidth feature off and on. You can set this independently for AM and SSB. Ideally to zero, because it automatically resets your bandwidth setting and since this is happening in steps, it sounds quite strange. The PL-660 uses a stepless dynamic envelope following low pass filter (which is I believe what they called “DNR).
7.) This is still a mystery to me. On the PL-880, this button apparently controls the line out level on FM. On the S-8800 it (ostensibly) seems to control the S-meter bias with numbers running from ’00’ to ‘+99’ and ‘-99′ for all bands. Positive values reduces the S-meter display which made me curious if it rather controls AGC level or gain at some stage, but it really seems to affect the S-meter display only.
8.) Radio off: Toggles the seconds display on the main clock (when the clock is displayed instead of frequency).
9.) Another important one: this controls the threshold of auto squelch/soft mute. If you want to turn that off, turn it down to ’00’ with the main tuning knob, then hit the ‘9’ key again. You need to do this for AM, FM and SSB separately.
The S-meter was indicating a permanent base level of 2 bars even at my remote beach listening post. But even though it can apparently be “calibrated”, a 5-bar indicator is quite a step backwards from the 99-step RSSI meter of the PL-880.
After an initial discharge and recharge cycle, the 2x2000mAh “18650” batteries gave me a continuous runtime of 21 hours. When you connect the charger and then turn on the radio, it stops charging unless – and this seems odd – you are in FM mode. A full charge while listening to FM radio took 4:41.
I had a pretty hard time making my mind up about this radio. It has so elaborate details, so much design improvement and costly parts went into it but I feel like it doesn’t quite meet the expectations Tecsun created with this radio. Sadly, it has a few things that were started ambitious and ended underwhelming.
It got a huge 2-coil loopstick and somehow they managed to make it perform slightly worse than a 70€-radio with not even half of that loopstick size, they gave it 2 external antenna ports but they disappoint MW enthusiasts right again by keeping the loopstick always active, and how FM could turn out less sensitive than many radios with the same Silicon Labs chip (including their own models) is beyond me.
They improved the front end but then they dropped the attenuator, which costs the overall flexibility and better overloading-resilience their other radios have, they fixed the SSB issues of the predecessors and introduced a free-floating BFO with a mind of its own.
The price tag is making these downers certainly weigh heavier, and I think without them this radio may have turned out to be a real classic.
On the plus side I found a radio that really excels on shortwave. Shortwave program listeners can feast on a most sensitive, selective, luxurious and well-behaved portable with a big sound and I think there’s probably no current portable that could compete with that.
Ham radio aficionados get improved SSB reception and if there wouldn’t be this “cheap 70s receiver trademark” unstable oscillator, it would come close to communications receiver performance levels (minus the frontend needed for big antenna voltages).
That the price reaches into the ballpark of pre-loved high-end(-ish) JRC/Icom/Yaesu communication receivers or buys you a mint-condition ICF-2010/2001D may seem like a problem too. But then again, none of those radios is perfect either, and only the Sony is a portable.
Despite the quirks, the S-8800 is still a great, valuable radio that revives an out-of-fashion style of radios in a pretty unique and modern way.
What a brilliant, critical review of the Tecsun S-8800! Thank you so much for taking the time to properly test and compare the S-8800 with the venerable PL-660 and the XHDATA D-808 (readers, also check out his review of the D-808).
You’re right, too, in that I’ve noticed some contradictions in reviews–I do wonder if part of this might be variations between US and EU versions of the radio, or perhaps small quirks in production runs.
No doubt, however, that the Tecsun S-8800 is a champion of the shortwave broadcast bands and its audio fidelity is in a class of its own.
Many thanks to SWLing Post contributor, 13dka, for the following guest post:
A review of the XHDATA D-808
After all the recent buzz about the new XHDATA D-808 I had to get one. I got mine 3 weeks ago and I couldn’t help comparing it a lot with my PL-660. The PL-660 lends itself to such a comparison: it turned out to be the most sensitive shortwave portable with SSB in some comparison tests, so it became some kind of benchmark radio for this class of receivers and it has the same coverage as the D-808. Here are my findings, let’s start with the important stuff:
13dka’s “happy place” on the German North Sea shore.
I always try new receivers at my favourite listening post at the (German) North Sea shore, many of you know how beneficial such a location is for DXing. My favorite spot there is far away from any houses, power lines or other interference sources on the land side, so besides some sheep-made noise the man-made noise is as low as it gets, measured less than -130dBm (which is the receiver noise) on a 1/2 lambda dipole above 10 MHz.
At the same time the close proximity to the water results in somewhat boosted signals, so I can assess both reception quality at the lowest sensitivity threshold and behavior with strong signals. Sometimes it lets me find quirks that would go unnoticed anywhere else.
Here are my findings with the D-808:
Since users in the US have little ways to test that, let me assure you that all rumors you may have heard about a deaf longwave are perfectly true: the European LW broadcast band is pretty much not existing on the D-808. All those reports (e.g. many to find in Amazon reviews) indicate that really all D-808 are affected. The PL-660 is known to be very deaf on LW as well but it picks up a few stations in the evening, only some of them leave a faint clue on the D-808 and it can’t pick up BBC 4 on 198kHz even at night.
The signal meter indicates that it gains some sensitivity only above 300kHz, but from there it quickly starts to beat the PL-660 – during the day I can hear all of the local NDBs, something I can’t say about the PL-660.
AM broadcast band
This continues throughout the AM broadcast range – best tested during the day and on early evenings, the D-808 lets me ID weak stations that are just not there (yet) on the PL-660. Being noticeably better than the Tecsun, I then compared it to my old Grundig Satellit 400 (which has an average sensitivity on MW) and the D-808 matches its performance perfectly. So perhaps it’s not exactly a MW DX machine with just its internal loopstick but it performs well enough to make the band enjoyable.
Trying that at night and indoors shows why the right time and a low-noise location (or alternatively proper test equipment) are so important for such comparisons: any weak station sticking out of the distant and local QRM there is not as weak as it sounds anymore, both QRM and wanted signal are now well above the sensitivity thresholds of both radios and so SNR is defined only by the QRM, not the receiver. That means both radios falsely appear to have exactly the same sensitivity.
Notwithstanding some duds, the PL-660 is known to be a little sensitivity monster on shortwave. When I don’t feel like putting up wires etc. for my SDR, I just take the Tecsun to the beach and through the years I own it, I’ve logged plenty of true DX (JA, VK/ZL or WWVH on a regular basis) with it there, just using the telescopic whip.
Only below 3 MHz it’s not all that great on the whip, and that’s where the D-808 beats it – listening to top band (160m) hams works surprisingly well for a 25 inch whip. Between 3 and 30MHz the D-808’s sensitivity appears to be almost on par with the PL-660, the PL-660 often wins in terms of intelligibility at the “minimum discernible signal” (MDS) threshold. For example, on a day with bad conditions Gander Radio on 6604kHz USB had a barely audible signal on both radios. But I could occasionally decipher some words on the Tecsun that didn’t make it through the noise on the D-808. These photo finish victories for the PL-660 can be observed across most bands, but it needs ridiculously weak signals to spot the difference.
This difference is partly due to the fact that the D-808 seems to be a tad more noisy and partly owed to the better speaker of the PL-660. But the PL-660 also sports the often frowned upon “soft muting” feature, thus creating an impression (or should I say illusion?) of a pretty quiet receiver. I find it hard to tell whether the D-808 is really noisier than the PL-660, or just lacking this permanent noise reduction. I think this feature potentially even increases intelligibility on SSB a tiny bit, but on AM it’s just disturbing and makes the Tecsun lose its sensitivity advantage. Bottom line is that the D-808 is at least very close to the PL-660 in terms of sensitivity on shortwave and I find that quite remarkable.
Both receivers are pretty identical in FM performance on their whip antennas. Sensitivity is good enough to pick up high-power stations more than 100km away in times without any elevated conditions. Both receivers don’t need much signal to make a station intelligible, so when conditions improve a tiny bit (“marginal” indications on the Hepburn Index map) the band already gets populated accordingly. One difference is the coverage: the PL-660 can be switched to cover the Japanese FM band (76-108MHz) only, the D-808 covers the old OIRT band (64-108MHz) on top. What makes the D-808 the winner is its RDS/RDBS capability and the size, it certainly has the sensitivity needed for some ad-hoc FM-DX when you find yourself bored on a hill or in sudden tropo conditions.
By the way: RDS gets decoded sufficiently fast and starts to show on signals with an SNR of at least 12dB (see the bit about the RSSI/SNR meter below). If the station transmits date information it will set the clock automatically, but when you go on a hunt for stations it may receive some garbage data that resets the clock to a wrong time. It may be best to turn on the automatic only occasionally to set the clock, then turning it off again.
The D-808 is at least as sensitive as my Alinco DJ-X11 scanner and skunks the rather deaf Tecsun in this band. Unlike the PL-660 and most other small receivers covering that band it has a squelch, which is by the way active on all bands.
What it lacks is the new 8.33 kHz channel spacing, the “Fast” tuning step is still 25 kHz (“Slow” is 1 kHz) and the scan searches the band in 25 kHz steps as well, so I have to tune in the new channels manually. But while it lacks the new spacing, it absolutely has the selectivity for it – the AM filters are all available on the air band as well and even the widest one is still good enough to separate adjacent channels sufficiently. My 6 times more pricey Alinco has the new 8.33 kHz channels but it can’t separate them at all.
The D-808 is a great air band receiver!
The PL-660 has 2 (I think unspecified) ceramic IF filters for SW, which are doing a good job serving 90% of all typical purposes for such a radio. The D-808 on the other hand utlizes the DSP for IF filtering and offers whopping 11 different bandwidths (6 on AM and 6 for SSB), this is even more than the PL-880! This sold the D-808 to me the most, for example I like to improve my very poor CW listening skills every so often, and always having an even narrower filter up the sleeve can save otherwise hopeless DX reception in the ham and broadcast bands. But are they any good?
The 500 Hz “CW filter” seems to have a rather slow cutoff, unlike a true 500 Hz CW-filter it leaves voice communication almost intelligible. Still beats trying to hear CW through a regular SSB filter though! The 1 kHz filter seems to be the only one with an offset lower skirt (=less bassy sound), which can be useful in some cases. I’m not quite getting the purpose of the 1.2 kHz filter, I think I’d prefer a 1.8 kHz filter for a step between 1 and 2.2 kHz. The 1.2 through 4 kHz filters have the steeper cutoff you’d expect from DSP filtering and serve their purpose pretty well. In the “Gander Radio” example above, the narrow filter on the PL-660 couldn’t keep 4XZ’s CW signal on 6607kHz in check, while the D-808’s 2.2kHz filter eliminated the CW signal completely. I’d still take the bandwidth figures with a grain of salt though.
Oddly, the published bandwidth for the AM filters seem to be “audio bandwidth” (or “per sideband”) figures rather than IF-bandwidths, so they equate to classic IF filters with 2/3,6/4/5/6/8 and 12 kHz bandwidth. The only overlap is 4 kHz, hence I say it’s 11 different bandwidths, not 10. I think these AM bandwidths should cover all requirements that might come up, on top of those you can try ECSS reception with the SSB filters.
On pretty much all of the tiny shortwave portables, SSB reception comes with some tradeoffs and the D-808 is no exception. When the PL-880 hit the market a few years ago, the amount of filters for SSB offered by the Si4735 DSP raised my hopes for improved SSB, but unfortunately the D-808 has the same problem that kept me from buying the PL-880 back then, and some on top:
Like the PL-880 (at least some of them), the D-808’s AGC has a way too slow attack rate, the first portion of any strong SSB/CW signal is distorted before the AGC levels back, and it increases gain fast enough that even short talking (or keying) pauses make the next syllable distorted again. This seems to plague most (if not all) Si4735-equipped radios, so that might be actually a bug of the DSP.
The chuffing noise is making tuning through the band quite bad in SSB mode, it’s even worse than the early digital “keypad”-style radios in the 1980s: every tuning step is causing first a short muting of the signal, then audio comes back with a loud “chuff” from the AGC kicking in with full gain – tuning sounds like a model railway steam engine sound chip gone mad. Luckily, fine tuning with the thumb wheel doesn’t have this issue.
Another issue is an occasional effect that sounds and feels like the filter drops out when you tune through the band. The chuffing sounds different and the background noise sounds wider with more hiss, then after a while (this can take several seconds) the filter pops back in with the regular puff from the AGC.
Slow mode switching
When switching to SSB a “loading bar” shows up first, the entire process between hitting the “SSB” button and getting reception again takes 5 seconds. Actually, these radios basically consist of a “radio-on-a-chip” and a microcontroller so it really might be a loading bar we see there. This controller seems to be not exactly fast in the D-808 anyway, so even using the tuning knob comes with occasional hesitations – I advance the main tuning encoder one indention and the frequency changes only 1-2 seconds later. Changing bands is not exactly fast either but at least toggling between USB and LSB works instantaneously.
In comparison, the PL-660 has none of these issues – tuning is smooth and fast, and the AGC is less borked. So tuning the D-808 isn’t elegant and it doesn’t sound exactly beautiful on SSB. On the other hand it has great frequency stability, great selectivity and sensitivity and I can hear what I want to hear anyway. At 1/3 of the price for a PL-880 and pocket-friendly 2/3 of its size I decided to avoid overrating the quirks.
… is fortunately less odd. The chuffing gets replaced by less annoying muting when tuning in AM mode, the ability to quickly scan a band with the main tuning knob seems to be less hindered by that. The PL-660 has a mediocre sync detector and the D-808 has not, but it can score with easier ECSS reception through its much less fiddly fine tuning in 10 Hz-steps (range +/- 990 Hz with the last digit omitted in the display) and the choice of filters is a clear advantage over the Tecsun’s 2 bandwidths in tricky DX situations. As mentioned above, the Tecsun is also losing its sensitivity advantage due to the soft muting on AM, so its remaining big plus is the more pleasant speaker sound.
Signal handling capabilities
As mentioned above, signals can increase quite a bit in very close proximity to the water. When conditions were good, I’ve witnessed occasional overloading even with just the whip antenna on the PL-660 there. But the Tecsun has a 3-position sensitivity switch that first turns off the input amplifier and then adds an attenuator, so it can manage these situations by turning off the preamp and it happily digests signals from full size dipoles, long wires and active antennas with the built-in attenuator in the signal path.
The D-808 has no such thing and that makes it at least as vulnerable to overloading from good conditions or big antennas as the PL-660 without attenuation. At the beach it exhibited very faint intermodulation even at propagation conditions that were just “not quite as crappy as the current record low” when the Tecsun did not. They were so soft that I think this can’t be heard when the noise level is a bit higher, still a bit strange. Intermodulation products seem to show up most prominently around 7MHz, 10MHz and in the 15m ham band first.
Other than that, it seems to abide <10m/30ft of wire just fine and it gets along with my ML-200 active loop, currently indoors with a rigid 80cm aluminum loop, unless the RRI transmitters populate 49 and/or 41m after midnight. That station occasionally hits the 9+60 mark on my SDR with a dipole and when they’re on, the D-808 has to be tuned far away from these bands or disconnected from the loop to stop the pumping, desensitizing and intermodulation products. Interestingly, strong signals often make the filter drop out (as described under “SSB reception”) as well. A theory could be that this happens when an off-band signal (and/or the AGC causing “clipping”) makes an AD-converter run out of bits.
That even regular good signals outside the filter passband can trigger unwanted AGC action might be more or less common with most of those DSP radios. The massive worldwide contest activity on March 24/25 was a nice opportunity to test that. Even though I fled to the less crowded upper region of the 20m-band and it was an hour after sunset so the band was closing, I noticed the AGC was pumping a lot while listening to a contester with a moderate signal. It could be the the ceramic filters (which are said to have better out-of-band rejection) or just the way my Tecsun’s AGC works (or malfunctions) differently, however this effect is much less pronounced on the PL-660.
Frequency stability, accuracy, birdies, quirks
Both receivers are generally very stable and don’t exhibit a noticeable warm-up drift. Just to see what happens, I took the D-808 from a very warm apartment into cold (-5°C/28F) and stormy weather outside. The internal (and very slow changing) thermometer of the D-808 indicated an internal temperature drop of 12°C within 10 minutes and if there was a drift at all, it drifted less than 10Hz.
Comparing the BFO frequency accuracy (using RWM on 4996 and 9996 kHz) brought up some slight offsets across the coverage range, with different curves for LSB and USB:
So particularly on LSB, the offset on my D-808 varies quite a bit over the entire coverage range but I think this is within the allowable tolerance for such a radio. The PL-660 has slightly better results but it also has a center-indented fine-tuning knob making small corrections quite difficult. In AM mode they are both spot on.
So far I couldn’t find birdies anywhere on the D-808. The PL-660 is pretty clean on shortwave too, but it has hefty birdies around 100, 200 and 970kHz, despite the efforts Tecsun has put into shielding and clean PCB design.
SWLing Post reader Mike reported a loud “pop” when changing bands. I can replicate that but it’s not that loud here. I’m getting a much louder pop (independent from the volume setting like Mike’s pop) when using the band scan function though. If I’m tuned to a station and another station (strong enough to stop the scan) is quite close (10-15 kHz) to the station where the scan was started, a loud pop will be heard when the scan stops at the other station.
Both receivers have some “thin plastic” feel to me, but while my PL-660 has some slightly rattly and wiggly buttons and knobs rubbing against the casing, the D-808 has none of those and feels a tad more solid. The tuning knob and the fine-tuning thumbwheel have quite strong detents, so they are not very prone to unintentional detuning. The D-808 lacks the weight and the tiny rubber feet that keep the Tecsun fixed on the table.
I’ve seen quite a few complaints/misunderstandings about the D-808’s operation and I think this is due to the fact that there is a fundamental difference between e.g. many Tecsuns and the D-808 in terms of keypad usage: the PL-660 is prioritizing direct frequency input and the D-808 makes memory operation easier. It couldn’t be any easier indeed – depressing a number button on the keypad for more than 3s stores a frequency, hitting it shortly loads that frequency. “Page” button, then number key loads the memory pages 0-9 on each band (so each band has 100 memories). Like the PL-660, the memories store frequencies only, not the mode and also not the bandwidth (despite the manual claims they do). Also differing from the manual, the selected bandwidth stays put per mode and doesn’t reset to a default setting.
Direct frequency input needs to be initated with the “Freq” button though, and in some cases (shortwave frequency <10,000kHz) you need to hit it again to enter the frequency. The D-808 has up/down buttons in addition to the main tuning knob, they are stepping through the bands in the “Fast” step width so you can pretty much always leave the tuning knob on “Slow” . Pressing these buttons longer than 3s starts the band scan. Holding each of the left side band buttons starts the “ATS” scan-and-save-to-memory automatic.
The D-808 shares the “power off” settings scheme with the Tecsuns – some functions like LW on/off, the FM band coverage and so on are set when the radio is off. These functions are labeled in orange above the corresponding buttons and I share the criticism about the color scheme, which is really hard to read in less than optimum lighting conditions. Also, some of the labels are actually “power on” functions marked in the same color, like the “METER” function on the SW band button (hit the SW button repeatedly to step through the broadcast bands) or the USB/LSB switching and key lock functions activated with the “Info” button.
Despite the size difference, readability of the display is fine on both receivers. Backlight control is fundamentally different tho: You can turn off the automatic backlight on the PL-660 but you can’t turn it permanently on, the D-808’s light button toggles between “permanently on” and off but you can’t turn off the automatic. The backlight is objectionably bright on the D-808, the upside is that it serves well as a reading light and the light reflected off your hand can illuminate the buttons sufficiently to substitute the missing button lighting.
Some random things I like:
Like the PL-880 and some other Tecsun radios, it has a somewhat odd “dB over 1 microvolt”-like signal indicator. It lacks the negative figures needed to properly represent the ~S0-S3 range, it just goes from ’00’ to ’99’ and it’s strangely labeled as “dBu” but technicalities aside, it is a signal indication in 100 steps which is certainly more useful than a 5 bar indicator. According to reports, other receivers with this RSSI don’t seem to use the entire display range and end at ’75’ or less. However I can see the D-808 showing ’99’ when I’m at our airstrip and the tower transmits.
The second pair of digits is a crude calculation of receiver (not audio!) SNR, which can be useful in conjunction with the signal strength meter, e.g. for adjusting or comparing antennas and so on, and it works best with AM and FM signals.
“18650”-batteries have a very high energy density at a very low weight, and in the D-808 they meet a radio with a very moderate power consumption. As a result, the provided 2,000mAh battery powered the radio continuously for remarkable 32 hours, 14 of them with the display light on! For comparison, the heavier (and more expensive) 2,500mAh Ni-MH batteries in my PL-660 last for 24 hours only.
It seems the quality of the packaged battery is all over the place though, one user reports “have to charge every day”, another one “28 hours”. If in doubt, a Panasonic 3,400mAh battery (this is the current technical limit for 18650s, don’t fall for fake “10,000mAh” offers seen on Amazon and eBay!) should last for a long weekend even if you’re listening all day. Make sure you buy the “protected” type, the other flavor (used e.g. in electric cigarettes) doesn’t work. If you happen to be a high-performance flashlight fan, you may already have a bunch of batteries to keep the D-808 going forever.
The manual claims that the D-808 can’t be charged when it’s on but I found that’s not quite true–it sure takes much more time but I could top off a slightly discharged battery just fine.
Charging it from a USB charger or laptop USB port introduces some additional noise on AM/SW of course, trying a cheap power bank worked out much better in this regard.
A true “Walkman” for SWLs
The PL-660 fits in some big pockets only and weighs more than a pound. The D-808 has only 2/3 of the Tecsun’s size and I can stuff it conveniently into all of my jacket’s side pockets (tuning knob ahead) so the whip can stick out easily without getting into my way at all. It has at most half the weight of the Tecsun, it weighs less than my smartphone!
This is making an old dream come true for me – a full-featured “communication receiver” (well, almost) that’s “wearable”, one that allows me to enjoy hands-free and hassle-free full shortwave reception on all bands without compromises (particularly in sensitivity) when I do the boring walks the doctor prescribed!
Outsides where the noises of the digital world are gone, the D-808 presents all bands almost as filled as my dipole at home and so there’s always an interesting QSO or some overseas radio program to enjoy. To give you an idea on what I mean by “no compromises”: my companion on today’s walk was NY2PO from upstate NY (3,728mi/6,000km away) on 40m, constantly coming in with a signal allowing for convenient listening, despite the bad conditions (SFI=68 A=10).
I think this may be the first time a radio with so many features and such a high sensitivity comes in such a small package – all handheld scanners with SW and SSB were an expensive atrocity on shortwave, the late ICF-7600 was slightly bigger, less sensitive and SSB was not its strength. The only radio with even more features and similar dimensions would be the “Reuter Pocket” SDR but that might be less sensitive on a whip, it lacks the air band, it has a 1-digit battery runtime and a 4-digit price tag. The only other affordable radio that could fit that bill would be the even smaller Tecsun PL-365 SSB, but it lacks an SSB filter, it has no RDS and no air band and I’d be curious if it can match the sensitivity of the XHDATA.
The D-808 can score in 3 bands (Air, FM (due to RDS) and AM) with its sensitivity, the PL-660 only on LW (due to the fact it actually receives something there) and by a narrow margin on shortwave. The Tecsun’s (perceived) lower noise floor, better speaker sound, better tuning and built-in attenuator is countered by a much wider choice of filters, better fine tuning control, better portability and the better battery endurance of the D-808. The latter also has a number of less important features the former lacks, on the other hand the Tecsun lacks the many quirks of the D-808. It’s up to you to weigh the advantages of each to find your personal favorite, the D-808 struggled a bit to become mine but at the end I couldn’t help enjoying this little radio a lot.
There is much room for improvement though – for example the slightly borked control of the DSP, the chuffing/tuning and AGC issues on SSB let the D-808 miss the title “most stunning cheap little radio ever” by a hair.
For me, the unique combination of size, sensitivity and selectivity is making up for the shortcomings, it certainly remains a very interesting radio and I can’t remember carrying one around that much, ever.
What a brilliant, detailed assessment of the D-808! Thank you so much for sharing this! I’m absolutely jealous of your North Sea listening location–looks to be idyllic!