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I also wanted to do a little shortwave listening after completing the activation. I had no idea what propagation would be like, but thought I’d tune around below the 20 meter band where the antenna was currently resonant.
I deployed the CHA Emcomm III Portable random wire antenna which, I must say, is a superb shortwave listening antenna for the field.
Since you can’t see the antenna in the first photo below, I marked up the second one. The blue line represents the 73′ radiator, and the green line the counterpoise: Here’s the short video I made around the 22 meter band:
I had planned to make a few audio recordings via the built-in digital recorder but I left my MicroSD card at home. No worries, though, as I plan to make some recordings for readers to compare in the coming days if time allows.
If you have any questions about the IC-705, feel free to ask in comments.
The following review was first published in the September 2020 issue of The Spectrum Monitor magazine:
The HobbyPCB IQ32 transceiver fills a special niche in the ham radio world
This summer, I’ve been exploring the world of general coverage QRP transceivers. I’ve been taking my LnR Precision LD-11, Elecraft KX3 and KX2 into the field; and I’ve just finished a comprehensive review of the Xiegu G90. I also have a TX-500 and IC-705 arriving in the near future [update].
Yes, I’ll admit, I’m a devotee of the “all-in-one” nature of the latest model portable QRP transceivers.
Most of the QRP transceivers now on the market are products of large, popular ham radio manufacturers. Usually, a company will come up with a product concept, follow through with their market research, then design, develop, and produce the radio. In fairness, that’s an over-simplification of the process, but let’s just call it a “top down” design approach––meaning, the product idea is generated within the company, and is often based upon customer feedback.
Not all ham radio products come about this way, though. Some have more “grassroots” or collaborative origin.
The HobbyPCB IQ32
(Image Source: HobbyPCB)
I first noticed the HobbyPCB IQ32 transceiver at the Dayton Hamvention a few years ago. I checked it out carefully at their booth, and recall a crowd gathering around their table. Noting this, I decided, at a later time, I would also find an opportunity to check out the radio in more detail.
A couple of months ago, I was working on my list of General Coverage QRP Transceivers and asked for help filling in details of any radios I’d forgotten. A reader commented and reminded me that the IQ32 was, indeed, general coverage.
At this point, I reached out to HobbyPCB and asked for a loaner unit to explore for a few weeks. The company very kindly sent one my way some weeks ago, and I’ve been testing it on the air ever since.
Form factor
When I received the IQ32 package, I was surprised by how lightweight this transceiver is: a mere 1.5 lbs (700 grams) packs it all in one compact package.
The chassis is made of aluminum and incredibly sturdy. It even includes side panel extensions to protect the front faceplate and knobs.
The IQ32 sports a 3.2″ color LCD touch-screen display large enough to contain all of the functions, a spectrum display, and even an area for text––both transmitted and received in PSK31 and CW. The display is reminiscent of the uBITX V6 I recently reviewed. It is recommended that the operator uses a blunt plastic stylus (or retracted ballpoint pen) for navigating the color screen, since several of the menu settings, memories, and the like require some fairly precise tapping. The graphic user interface (GUI) feels a bit like what I’d expect to find on a piece of test equipment: a bit old school, but nonetheless quite functional.
The main encoder and selector knobs are lightweight and made of some sort of plastic or nylon. They work quite well––but if I owned an IQ32, I believe one of the first things I’d do is replace those with a lightweight aluminum equivalent.
As I mentioned earlier, the weight of the IQ32 is very reasonable at 1.5 lbs. I don’t think I’d even notice it packed in a backpack.
The IQ32, like the recently released Lab599 TCX-500, lacks an internal speaker. However, my unit came with a speaker microphone, which works fine.
The right side panel of the IQ32 has a toggle power switch, power amplifier connection, power port (5mm X 2.1mm, positive tip), PS2 keyboard connector, USB Type A, and a BNC antenna port. The left side has a 3.5mm I/Q Output, 3.5mm headphone jack, 3.5mm speaker/mic port, and a 3.5mm CW key input.
The IQ32 also has two legs that can be adjusted so that the radio will prop up at a comfortable angle for operation. The legs can be a bit finicky to adjust and keep in place, so I preferred using an angled radio support I use for my Elecraft KX3.
A collaboration
The IQ32 also feels like a project joint effort, bringing to mind the old chocolate-peanut butter cup commercial of a bygone era: “My chocolate got mixed with your peanut butter!” And or, “My peanut butter got mixed with your chocolate!”
Curious about this seeming blend of radio ideas, I reached out to Jim Veach (WA2EUJ) at HobbyPCB for more information; he gave me a little history behind the IQ32.
Jim writes:
The IQ32 is the fusion of two products: the HobbyPCB RS-HFIQ, and the STM32-SDR.
The RS-HFIQ was designed to be a 80-10M, 5W soundcard-based SDR––similar to the popular Softrock SDRs with some expansions and revisions.
The STM32-SDR was designed to work with a soundcard-based SDR and [thus] eliminate the need for a PC and provide stand-alone operation.
Inside the IQ32 is a mostly stock RS-HFIQ (in fact, we offered an upgrade kit so RS-HFIQ owners could go the IQ32 route) and a custom version of the STM-32 […] specifically for the IQ32.
The original development of the STM32 [began] a few years ago when PSK31 was the digital mode du jour and [the] PS2 keyboard roamed the land. The firmware team recently released the current FW, which greatly expanded the CW modes and reworked the memory structure based on user input.
And there you have it: even though this unique little rig has been around for a few years, I’m impressed that they continue to refine it and upgrade the firmware. Indeed, if the community of IQ32 users grow, they may be able to do even more.
On the air
To be clear, my intention here isn’t to conduct a comparative review of the IQ32. I simply want to convey what I’ve learned in the process of playing with the rig and trying out some of its unique features.
Immediately after unboxing the radio, I hooked it up to my main skyloop antenna, plugged in the power supply that accompanied the radio, then plugged in the handheld speaker mic.
I discovered rather quickly that the IQ32 user interface takes a different approach than any other transceiver I’ve ever tested. Instead of one main user interface window in which you navigate modes, frequencies, and perhaps alter spectrum and bandwidth settings, the IQ32 has a different screen layout for each mode. It’s as if each mode––SSB, PSK31, CW, etc.––has its own “page.”
Despite the very minimal controls, you can adjust many of the IQ32s settings, macros, and memories in a very granular way via the settings pages using a stylus for fine control of the screen. On the flip side, during operation, it can be frustrating when adjustments need to be made quickly between the AF Gain, RF Gain, CW Speed, and AGC, as they all use the same multi-function knob and switching between them requires several screen taps––not as quick a process as one might prefer.
Indeed, the IQ32 isn’t immediately as intuitive as most commercially-marketed radios. But once you fully understand the settings and modes pages, it becomes easy to navigate. Note: I would advise any future owner of an IQ32 to read the manual in advance. I did this, and it certainly helped. I should add here that the IQ32 manual is one of the most comprehensive I’ve read––especially considering its collaborative roots.
Now, let’s talk modes.
SSB
Since the IQ32 requires a PS2 keyboard for PSK31, and optionally for CW, I tried my hand at SSB first.
After learning how to switch modes and filter settings, I hopped on the air. Instead of calling CQ, I decided instead to seek a park activator in the POTA program via the POTA spots website. Within 10 minutes, I made contact with two parks: one in Pennsylvania and one in Florida on the 40 and 20 meter bands, respectively. While both parks gave me a “5×9” report, I seriously doubt it was accurate based on their own signal strength. (Some park activators, like contesters, only give 5×9 reports.)
Still, my success in contacting these two parks told me that the mic settings were probably suitable and that the audio had enough punch on 5 watts to be heard. To confirm, I called CQ a few times and listened to my own signal at a KiwiSDR site in Maryland. The signal was about 5×5, but the audio was clear, clean, and had excellent fidelity.
Over the past few weeks I’ve worked dozens of stations across North America with the IQ32.
PSK31
One of the very unique features of the IQ32 is its ability to natively encode and decode PSK31. This was the second mode I was eager to try.
To use PSK31 on the IQ32, a PS2 keyboard (or USB keyboard with PS2 adapter) must be connected. I searched my shack in vain for a PS2 keyboard, but fortunately, my friend Vlado (N3CZ) came to the rescue and let me borrow one of his keyboards.
Again, note: IQ32 beginners should certainly plan to read the PSK31 section of the IQ32 manual prior to attempting a PSK31 QSO. For starters, you’ll want to enter in your personal information into the tags settings so that you can use your keyboard function keys to automatically send CQs and to answer calls. The manual will also walk you through any other necessary settings.
Once I had everything set up, I started calling CQ on the 20 meter band; unfortunately I had no luck snagging a station. This had less to do with the radio and much more to do with the mode, which has, alas, fallen out of popularity since the advent of FT8. It’s a shame, really, because although PSK31 is a digital mode, it feels much more like a proper QSO than FT8, in my opinion. While I have a lot of respect for FT8, with PSK31, you can, as we hams say, “rag-chew”––a much more personal interaction.
And rag-chewing is exactly what I did. I contacted a friend, we set a sched for a PSK31 QSO, and it was, indeed, fun. The IQ32 has a screen with enough text space so that it’s easy to follow and to read. In fact, with this radio, I don’t feel like a computer is needed.
With the keyboard attached, PSK31 just works…and works quite well. I really like the way this feature has been implemented in the IQ32.
CW
Truly, the IQ32 actually has a lot to offer the CW operator. The IQ32 supports Iambic keyer modes A and B, with speeds up to 35 wpm. You can also adjust the weight of the dits and dahs. The IQ32 doesn’t support full break-in QSK, however: there is a slight delay after sending before the relay puts the radio back into receive mode. At present, this delay is not manually adjustable but is, rather, based on the selected keyer speed.
I’ve been very pleased using the IQ32 in CW mode with my Begali paddles and Vibroplex single lever paddle.
Of course, a really unique feature of this rig is that it provides the operator with the means to use the PS2 keyboard to send CW, just as you can with the PSK31. At present, there is no CW decoder, but for those who feel their fist isn’t quite up to par, you can surprise the operator on the other end by sending perfectly formed and spaced CW by simply typing it on the keyboard. Herein lies a very unique feature and application for the IQ32.
Indeed, as a frequent Parks On The Air (POTA) field activator, I rely very heavily on memory keyers to call CQ, send a park number, as well as give my thanks and 73s to those who contact me. Using a pre-programmed message means that I then have time to log a station while it sends, and to ensure my code is cleaner when I send park numbers––especially since I don’t exactly excel at sending strings of numbers!
With the IQ32, I find I can program full CW messages to play when I simply press one of the function keys on the keyboard. This gives me much better flexibility and control than, say, the built-in memory keyer on my venerable Elecraft KX2.
With the IQ32, a CW op would actually have the choice of never even touching a key, and just sending all messages with the keyboard. While I could never see myself doing that (as I quite enjoy sending CW with a key), the flexibility of pre-programming an array of CW memory messages and having them conveniently at hand is nonetheless quite appealing.
As a CW operator, I’m quite pleased with the IQ32. My only wish would be for a slightly shorter relay hang time for use in contesting or on Field Day.
The IQ32 Niche
While I wouldn’t necessarily recommend the IQ32 as a first transceiver to a newly-minted ham, I can certainly envision a niche market for this unique rig.
For one, I think the IQ32 could satisfy those operators who desire a very clean and stable transmitter. The IQ32 sports a Class A 5-watt power amplifier with individual low-pass filters for each band that exceed FCC requirements for spectral purity. It also has a Temperature-Compensated Crystal Oscillator (TXCO) for frequency stability––truly, this is not common in a radio of this price class.
For another, the IQ32 could be used as a driver for a transverter when operating on VHF or UHF. Another of its unique and useful features is that the user can set an offset to display the transverter output frequency rather than the IQ32-driven frequency.
And, finally, let’s face it: I know of few other radios that you can take to the field, hook up a keyboard, and natively send and decode PSK-31 transmissions. My KX2 can do this to a degree, but I have to input the text as CW, and the number of characters in the display is quite limited. The IQ32 is robust enough to permit you to carry on PSK-31 rag-chews, if you wish. If this is your thing, you’ll definitely want to play with this rig.
Being able to send CW with a keyboard and pre-programmed messages also means CW operators could make their workflow much more efficient in either the shack or the field.
In conclusion, I’ll admit that the IQ32 isn’t as intuitive as other radios and that the ergonomics leave room for improvement. But it’s still a cool little radio. If, after having read this tour of the IQ32, you feel like you’re in this radio’s niche market, then definitely reach out to HobbyPCB: I’ve found their customer care and support to be absolutely benchmark.
All in all, I’ve had a lot of fun tinkering with this unique general coverage QRP transceiver; I expect others like me will, too. Many thanks to HobbyPCB and the IQ32 crew for letting me take a deep dive into this very special little rig!
Many thanks to SWLing Post contributor, Jaap de Goede, for the following guest posts:
Operating the TECSUN PL-330 without an English manual
by Jaap de Goede
Introduction
Inspired by my father, I like listening to radio transmissions for the last 60 years. That includes listening to shortwave transmissions. In my collection there are a number of radios including computer based SDR-receivers. The TECSUN PL-330 is a shortwave portable radio with SSB and digital readout.
I’d like to share my operating experience of the PL-330 and throughout I will now and then compare this radio to similar radios in my collection: Eton Satellit,XHDATA D-808 and CountyComm GP5-SSB (AKA Tecsun PL-365).
To be clear the PL-330 used here is a Chinese domestic version, probably manufactured in July 2020. An English manual was not available at the time of writing. In the meantime, the English manual of the Tecsun PL-990 helped to figure out a number of the features of the PL-330. Newer manufacturing batches might contain other firmware and that could change the way of operating.
Size and sound
With a volume of about 18 cubic inches the PL-330 is less than 20 cubic inches. It easily fits the pocket of my jeans. 20 cubic inches (unofficially) classifies it as an Ultralight DX radio. The smallest radio of the four is the GP5-SSB with 14 cubic inches. The Satellit is the largest of the four and the size of these radios can be determined by the eye but by the ear as well.
The PL-330 has digital VOLUME control and the volume level is indicated on the display. In contradiction, the three other radios have analog volume control. All radios have a 3.5 mm socket for a stereo headset. A nice feature of the PL-330 is that the FM stereo decoder only works with a plugged-in headset. Else FM remains in mono. I think that’s a very clever feature because why would the stereo decoder degrade the mono-sound through the speaker in case of poor FM stereo reception?
Personal audio quality ranking from best to worst:
Satellit
PL-330 and D-808
GP5-SSB
Power and Batteries
The PL-330 is supplied with a BL-5C battery of 1000 mAh. The battery can be charged in the radio through though a micro USB port. The display permanently shows battery status, regardless whether the radio is on or off. USB makes it very easy to charge from any external USB charger or an external USB battery. Here a quick comparison of the powering of the four radios:
Radio
Battery
Charging Port
Tecsun-PL-330
1 x BL-5C
Micro USB
CountyComm GP5
3 x AA NiMH
Mini USB
XHDATA D-808
1 x 18650
Micro USB
Eton Satellit
4 x AA NiMH
Bus
I don’t have runtime figures. I just charge when indicated on the radio’s display and carry a spare USB battery to charge the radio in case.
Antenna and Backlit
All four radios have an extensible whip antenna (what else would you expect). Also, all four radios have a 3.5 mm socket for an external antenna. The only radio with an antenna attenuator switch is the Satellit.
All four radios have backlit. But a feature that none of the other radios has is the ability with the PL-330 to toggle the backlit between “always on” or “automatic off”. Just hold and press the 5 button to toggle between the two modes. For comparison, the Satellit has the nicest illuminated display of all four, while the D-808 is way too bright.
Supported Radio Bands
The PL-330 supports the following radio bands:
Long Wave (153-513 kHz)
Medium Wave (520-1710 kHz or 522-1620 kHz)
Short Wave (1711-29999 kHz)
FM broadcast (64-108 MHz)
Radio Band and Demodulation Selection
To enable or disable the LW-band you must long press the 2 button when the radio is powered off. When the radio is powered on and LW has been enabled you can select between LW and MW by short press of the MW/LW button.
The American or Rest of World MW-band plan can be toggled by long press the 3 button when powered off. When the radio is powered on you can select between MW by short press of the MW/LW button.
To select the regional FM-band plan you should long press the 0 button when the radio is powered off. When the radio is powered on the FM-band can be selected by short press FM/ST. button.
When the radio is powered on the SW-band can be selected by short press < or > button.
In LW, MW and SW bands de-modulation can be AM, SSB and AM synchronous (SYNC). A short press of the SSB button toggles between AM and SSB. A long press of the SSB button toggles between AM/SSB and AM synchronous mode.
A nice feature within the SW band is that you can quickly skip to pre-determined broadcast or HAM bands. In AM and SSB mode you can skip to the desired band by pressing < or > button. The following bands can be selected and indicated in the display:
There is one (digital) TUNING dial for all tuning operation in any radio band. It only tunes up and down the bands and has no other function. (That makes tuning with the PL-330 so easy compared to the other three radios with multifunction dials.) Depending on the selected band and de-modulation the tuning steps can be altered by the STEP button.
In the LW and MW bands for AM demodulation the step size can be toggled between 1 kHz and 10/9 kHz by short press of the STEP button.
In SW for AM demodulation the step size can be toggled between 1 kHz and 5 kHz by short press of the STEP button.
In the SW band for SSB and synchronous mode the step size can be toggled between 10 Hz, 1 kHz and 5 kHz by short press of the STEP button. My other three portable radios, but only plus or minus 1 kHz of the actual frequency in steps of 10Hz. The PL-330 has continuous fine tuning in SSB; you can tune the entire SW band up and down in steps of 10 Hz. However, I noticed that the step size can change from 10 Hz to 50 Hz in case you turn the TUNING dial fast.
In the FM band the step size can be toggled between 100 kHz and 10 kHz by short press of the STEP button.
Bandwidth Settings
For AM and SSB you can change the bandwidth by pressing the AM BW button, turn the VOLUME dial to the desired bandwidth and press the AM BW button again.
I decided to purchase the PL-330 because of my good and bad experience with the GP5-SSB (PL-365). The PL-365 is super portable and I think ETM is great for occasional shortwave listening. However, without direct frequency entry the GP5-SSAB is a nightmare to operate just now and then. Now the PL-330 has an enhanced version of ETM: ETM+. No other radio has such a feature and I think ETM+ is fantastic.
ETM + provides 24 ETM banks that are chosen automatically based on the hour. Every hour you can press and hold the ETM button to initiate a (new or renewed) shortwave scan. It will display “E” plus the hour in 24 hours format like E00 to E23 depending on the time. When you quick press the ETM button it recalls the memory bank according to the time. As an example, when you quick press the ETM button at 15:24h it will recall bank E15. Then you can select the memory locations stored in the bank by turning the TUNING dial.
To toggle between ETM and Tuning mode press the ETM button.
In addition to ETM memories, the PL-330 has a lot of memories but lacks alpha tags. I really have difficulties remembering what I put in those memories. I hardly use them. The only one of the four that has alpha tags is the Eton Satellit, that makes things a lot easier.
Memories can be automatically populated in a bank separate from the ETM banks by using the Automatic Tuning and Storage (ATS) function. All four radios have ATS and I think it’s only convenient for FM. It works like:
Press FM/ST. to select FM Band
Press and hold FM/ST. to start ATS
Use the TUNING dial to select from the stored FM stations
To toggle between Memory and Frequency tuning mode simply press the VM/VF button.
Bugs or Features
With the DISPLAY button you can change the upper right part of the display between:
Signal strength
Clock
Preset (only in VM Mode)
Alarm time
The display always returns to signal strength after a few seconds. Except if time is chosen with a long press of the DISPLAY button. Nevertheless, the display returns to signal strength after applying any operation, including volume change. I’m not sure if this is a feature or a bug.
When using a headphone and changing volume, sometimes the sound is cut off. By changing the volume again, it comes back. Seems like a bug, not a feature.
I tried AM synchronous mode. It works like on the Satellit: poor. I would recommend to make this mode hidden or make it work well.
Universal Serial Bus
When connecting the radio with an USB cable to a PC, its operating system does not show any connection information. If the radio would have USB logic apart from charging, connection information would have showed up. I assume there is no way to update firmware via USB.
Hidden Features
Without an English manual, and maybe even with a Chinese manual I couldn’t understand all functions.
When the radio is powered off:
Press and hold VF/VM shows all items of the display.
Press and hold 8 toggles display clock in “HH:MM” and “HH:MM: SS”
Press and hold 3 in MW/LW band toggles between internal ferrite and external whip antenna
Press and hold Enter shows “dEL ALL”, probably delete all (except what is all)?
Press and hold M shows numbers, no idea.
Press and hold 0 shows “PO []”, no idea.
There seems to be a combination to show the firmware version.
Missing Features
RDS display would be welcome. Even though the PL-330 shares the radio chip with the D-808 and the Satellit, the PL-330 does not display FM Radio Data System (RDS) on its display. Backlit buttons would be a welcome for operation in the dark. (Although you’ll quickly get used to the button layout.)
Features I didn’t miss
None of the four radios has DAB+ or HD radio. For DAB+ reception I use a Sony XDR-S41D and I can’t receive HD radio in Europe. DAB+ and HD radio could make the radio way more expensive and I prefer good SW performance anyway.
The possibility to upgrade firmware would be convenient. But I understand constraints of costs and the liability of bricking the radio.
The Satellit and D-808 support the Air band (108-135 MHz). That is ok for occasional listening to one single channel, but forget about channel scanning. I have my Bearcat UBC XLT125 VHF/UHF scanner for that purpose.
Conclusion
Like I started, I’m an occasional shortwave listener. I couldn’t really tell the difference in radio performance between the four radios. Of course, the best radio is the one you have with you. And because of its size, easy operation with a single tuning dial and features like ETM+, the PL-330 is probably the best portable shortwave receiver at the moment (for me ?). Thanks to Tecsun!
Jaap de Goede
October 2020
Many thanks, Jaap, for taking the time and care to put together this excellent overview of the Tecsun PL-330! This will serve nicely as an operation manual. Your father would be proud of you! 🙂
Readers: Please note that you can also download Jaap’s PL-330 guide as a printable PDF document by clicking here. The PDF has even better formatting as Jaap has used operation manual styled fonts to indicate button labels and functions.
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!
Practical results
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:
SSB
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
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.
NFM
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.
AM reception
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:
“Pseudo”-Sync
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.
Selectivity
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.
AGC
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.
Operation, ergonomics
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.
A number of SWLing Post readers have been asking about SSB audio characteristics on the new Tecsun PL-990.
Earlier this week, I took a moment while visiting family to make a few quick comparison videos with the PL-880 outdoors and away from RFI.
As I mention in the videos, there are a lot of cicadas singing in the background and you can also hear a bit of road noise–not ideal for audio, but I had to take advantage of a break in the weather!
You should also note that this isn’t a sensitivity comparison. The radios were pretty close together–if measuring sensitivity, I would have spaced them much further apart. Rather, I hope these videos give you an idea of the audio characteristics in SSB (both CW narrow and voice) and one comparison in AM. If you’re curious about sensitivity and how the PL-990x compares, check out Dan Robinsons initial evaluation.
CW Audio: .5 kHz filter on the 80 meter band
CW Audio: .5 kHz filter on the 30 meter band
SSB audio: 75 meter band
AM Audio: 5 kHz filter WWV 10 MHz
My thoughts
While these videos are far from ideal, they should give you a real-word impression of audio characteristics.
Personally, I think the PL-990x is a much better performer in single sideband. The noise floor is lower, but I think that may have more to do with better filter implementation. I’ve always felt that the PL-880 audio sounds “wider” than the selected filter in the more narrow SSB selections.
In addition, the PL-990x exhibits better SSB stability that’s especially noticeable in CW. The PL-880, at times, almost sounds garbled in comparison.
I also mentioned in the last video that the audio sounds better on the PL-880. I should have qualified that statement a bit better.
In general, yes, the PL-880 audio sounds better because its built-in speaker has slightly better audio fidelity that’s most noticeable when listening to music on the FM band, or a strong local AM station. On shortwave, I feel like I actually prefer the PL-990 audio for all but the strongest stations although I do wish the PL-990 filter could be widened to 9 kHz like the PL-880.
PL-990x (pre-production) vs. PL-990 (production model)
Tecsun Radios Australia reached out and kindly sent me one of their PL-990 production model radios to compare with the PL-990x pre-production model from Anon-Co we’ve been testing up to this point. This has been incredibly helpful as I put together my PL-990 review for the 2021 World Radio TV Handbook.
As I’ve mentioned in previous posts, I feel it can be problematic using a pre-production model radio for review only because there can be differences in quality control when a small number of pre-production units are manufactured compared with a proper first production run (remember this case?).
I’ve only had the production model PL-990 for a few days and most of that time we’ve been dealing with the remnants of hurricane Sally moving through our area dumping torrential rains.
Last night, however, a massive tree fell across our road knocking out power for the better part of 5 hours. This gave me a perfect excuse to start my comparison indoors while rain continued outside.
Based on my comparisons last night, it appears performance is nearly identical between the production and pre-production models. I’ve still more testing to do, but my initial impressions are most positive. Very happy quality appears to be consistent.
The Par EndFedz EFT-MTR triband (40/30/20M) antenna
In July, I purchased a tiny QRP transceiver I’ve always wanted: the LnR Precision MTR-3B. It’s a genius, purpose-built little radio and a lot of fun to operate in the field.
It’s also rather bare-bones, only including a specific feature set built around ultra-portable CW operation.
While the MTR-3B has features like CW memory keying, a wide operating voltage (6-12 VDC), extremely low operating current (20 ma in receive), real-time 24 hour clock, and a full compliment of keying adjustments, it lacks other features like a volume control, SWR meter, speaker, and built-in antenna tuner.
Some of those may seem like big omissions but SOTA and POTA activators who like extremely lightweight/portable gear love the MTR-3B for being so purpose-built.
The MTR-3B (and its predecessors) operate on three bands: 40, 30, and 20 meters. These are, without a doubt, my favorite bands when operating portable since antenna lengths are reasonable.
Since the MTR-3B doesn’t have an internal ATU, you need to pack an external tuner or, better yet, a resonant antenna–ideally, one that can be used on all three bands.
Although many of my portable transceivers have built-in ATUs, I rarely use them because I primarily operate with resonant antennas. Resonant antennas are more efficient–giving you the maximum mileage per watt. In addition, they’re also more simple: connect them to the rig and hop on the air. No tuner or tuning required.
The EFT Trail-Friendly antenna is incredibly compact and quite easy to deploy.
I’ve mentioned in previous posts that I’m a big fan of the Par EndFedz Trail-friendly EFT tri-band antenna (above) which is resonant on 40, 20, and 10 meters. I’ve activated well over 130 parks with this little antenna.
After I took delivery of the MTR-3B, I borrowed the Trail-friendly EFT antenna from my KX2 field kit. It worked well on 40 and 20 meters, but it doesn’t cover the 30 meter band. Also, by borrowing the EFT from the KX2 kit, I broke one of my rules: never borrow from one field kit to feed another. This led to me leaving the EFT hanging in a tree at a remote park and returning a week later–a three hour round-trip(!!!)–to retrieve it. (FYI, in all fairness, I also blamed my trusty canine companion for this mishap!)
I was very pleased with this decision as I’m guessing LnR Precision wanted to hand off antenna production so they could focus on the very popular Mountain Topper transceiver line.
Vibroplex is owned by my buddy, Scott Robbins (W4PA), who is not only a successful entrepreneur, but also an award-winning contester and DXer. I’ve known Scott for years and knew he’d not only be a great steward of the Par product line, but also push new innovations.
I emailed Scott asking if Vibroplex had a field-portable antenna that would be resonant on 40, 30, and 20 meters. Turns out, there’s a Par antenna designed specifically to pair with the MTR-3 series transceivers: the Par EndFedz EFT-MTR.
The new EndFedz ® EFT-MTR is a 40m/30m/20m tri-band QRP antenna rated up to 25 watts. The “MTR” name was selected as LNR Precision developed this antenna to be the perfect companion to the wildly popular 40/30/20m Mountain Topper QRP transceiver. The EFT-MTR’s total length is 65′ of 22 AWG polystealth wire and weighs less than 4 ounces! It is built with the same high level of workmanship and quality that you have come to expect with all EndFedz ® antennas.
A particular innovation on this antenna: This EndFedz is a little different than previous designs. The user has the option to remove an SMA connector at the end of the 30M resonator to enable just 30 meters, or keep the SMA installed for 40 and 20 meters. Because of the broad bandwidth of the antenna, it is unlikely that it will require tuning in the vast majority of deployments. This is particularly true of 30 meters where the band is very narrow. As our tagline states, “They Just Work!”
Included with the EFT-MTR is the EndFedz Antenna Winder. Conveniently allowing winding up the antenna line to not have a tangled mess at the end. The winder will hold both the antenna and 25 feet of RG-174U coaxial cable (optional accessory).
Scott offered to send me an EFT-MTR to evaluate in the field (disclaimer: at no cost to me) and I accepted without hesitation, of course!
An EFT-MTR field review
I’ve taken the EFT-MTR antenna to three park activations at this point and have formed some opinions about it.
The EFT-MTR fits perfectly in a slide-in pocket in the main compartment of the Boot Boss.
First of all, I couldn’t be more pleased with the size as it fits perfectly in my MTR-3B field kit built around my Red Oxx Booty Boss pack.
I really like the built-in antenna winder: it’s larger than that of the EFT Trail-Friendly, but also much easier to wind up and manage post-activation.
I’ll admit, the length of the EFT-MTR was a bit surprising the first time I deployed it: 65 feet. Keep in mind, though, I had been used to a much shorter 41 foot radiator on the EFT Trail-friendly. Occasionally, I operate in spots where I simply don’t have the room to deploy a long antenna. I also worried that the EFT-MTR resonance might be negatively affected by winding its way through trees and over a branches. The MTR-3B transceiver does not like high SWR values and has no built-in SWR meter to monitor it. Last thing I wanted to do was harm the MTR finals.
You might be able to spot the feed point of the EFT-MTR at my activation of K-6952 this week.
Fortunately, winding its way through trees doesn’t seem to have a significant impact on SWR.
Each time I’ve taken the EFT-MTR to the field, I’ve also taken my KX2 which I’ve used to read the antenna’s SWR value. So far, the difference has only been negligible and SWR well within the tolerances of the MTR-3B. Score!
I should note here that since I’ve started using an arborist throw line, I’m also able to hang antennas much higher than I could before. This has had a huge impact on all of my field activities.
Removing the SMA cap changes the EFT-MTR from a 40/20 to a 30 meter resonant antenna.
To be resonant on 40, 20 and 30 meters, the EFT-MTR requires a field modification. On the coil about 2/3 the way up the antenna, there’s an SMA connector with a small screw on cap (see above). When the cap is on (thus completing the connection) the antenna is resonant on 40 and 20 meters. You must remove the cap for it to be resonant on 30 meters.
Since I’ve been using the EFT-MTR, I start an activation on 40 meters (which is typically my most productive band), then move to 20 meters (typically, my least productive). If I have the time, or need the extra contacts to confirm a valid activation, I lower the antenna, unscrew the SMA cap, and raise the antenna again.
I thought at first this would be a major pain, but it hasn’t. Now that I’m using an arborist throw line, it’s super easy to lower and raise antennas. But even when I’ve used fishing line, it really hasn’t been an issue.
The only issue I see is I’m afraid I’m going to lose that little SMA cap in the field. To prevent this, I’ve made it a routine to immediately put it in the internal zippered compartment of the Booty Boss pack. I might find a source for those caps, though, just in case I still lose this one.
I’ve been very pleased with the EFT-MTR’s performance. I’m guessing it’s actually higher gain than my beloved EFT Trail-Friendly antenna. On my last activation with the EFT-MTR, I knocked out eight 40 meter contacts in about eight minutes during a period of poor propagation. Note that the MTR-3B was only pushing 3 or 4 watts of power.
I then moved to 20 meters where, frankly, propagation was so crappy I didn’t hang out there long. Instead, I lowered the antenna, removed the SMA cap, and started calling on 30 meters. Within a few minutes, I racked up the rest of my contacts.
I was very pleased with how quickly the Reverse Beacon Network picked up my CQs and was thus auto-spotted on the POTA website.
Conclusion?
If you own a Mountain Topper MTR-3 series transceiver, I highly recommend the EFT-MTR antenna. As with my EFT Trail-friendly and Par sloper, the quality is top-shelf. I expect the EFT-MTR will last even longer than the EFT Trail-friendly since the winder is so accommodating and the in-line coil is designed so that it doesn’t snag on branches as easily.
I’m looking forward to much more field fun with the MTR-3B and EFT-MTR combo!