Shortwave listening and everything radio including reviews, broadcasting, ham radio, field operation, DXing, maker kits, travel, emergency gear, events, and more
As I stated in my review, the Skywave SSB is an impressive little receiver when DSP noises and birdies aren’t an issue. My Beta unit is a lot of fun to put on the air and has become my go-to “Swiss Army Knife” travel radio.
I will be testing an early second production unit of the CC Skywave SSB later this year and will post my evaluation here on the Post.
A few months ago, the radio manufacturer Tivdio contacted me to see if I would be interested in evaluating their new Tivdio HR-11S self-powered emergency radio. I receive requests like this frequently, and often pass on the opportunity since I generally don’t have the time to evaluate the overwhelming number of inexpensive DSP radios that have hit the market in the past few years.
But this time, I seriously considered it. There were two reasons I was interested in the HR-11S:
I purchased a Tivdio V-117 last year, and have been pretty pleased with it; indeed, I’m overdue a review on this unit. We’ve also posted several positive reviews of the Tivdio V-115.
At our non-profit ETOW, we’re always looking for reliable self-powered radios with shortwave for use in areas of the world where radio remains the primary news source.
Thus this radio is a rather rare breed. Tivdio dispatched the radio very quickly, but my work with the Radio Spectrum Archive and several other reviews already in the pipeline took priority.
I’ve had the HR-11S in service for several months, and have now explored every feature to some degree. What follows is my summary and review notes.
Green and Red radios are different models
First things first: note that I’m reviewing the GreenHR-11S. Tivdio also makes a Red version which is actually a different model number: the HR-11W.
The main difference between these models, as I understand it, is the green HR-11S is a shortwave version, and the red HR-11W is a NOAA weather radio version.
Both are useful; why not combine the two roles in one unit? I’m not surprised this radio can’t include both shortwave and NOAA weather radio. Through Ears To Our World, I’ve worked with self-powered DSP radios for many years, and know that a limitation of the DSP chip is that it can be set to feature either shortwave or weather radio, but not both, simultaneously, if both AM and FM are included.
Form factor
The HR-11S has a built-in solar panel.
The HR-11S adopts the standard “flashlight” form factor found in so many other self-powered radios. I think the flashlight functionality is a useful feature and results in a handy form factor. It’s compact, lightweight, and seems relatively sturdy, so is suitable for camping, travel, and off-grid utility.
Flashlight/Siren switch
A small switch on top toggles between four positions. The first two positions are off/on for the main white LED. Though the flashlight aperture is relatively small, the white LED provides enough luminosity to light your immediate path at night, and certainly more than enough to read by.
The third switch position engages a flashing red LED. The red LED is not terribly bright and I’m not sure how helpful this would be in an emergency situation.
The red LED is rather dim and can only flash.
I would much rather have the red LED maintain a steady beam which would be great for amateur astronomers, campers, or anyone else wishing to preserve their night vision.
The fourth position engages a LOUD siren. More than once when attempting to turn on the flashlight in the dark, I’ve accidentally engaged this pain-inducing feature. The switch is small, thus it’s very easy to engage the siren. In a quiet campground, this might annoy your neighbors––not to mention you, yourself. Of course, in an emergency situation, a loud siren could come in handy. I just wish its switch wasn’t combined with the flashlight switch.
The display HR-11S display is backlit and easy to read.
The HR-11S sports a keypad that allows direct frequency input––a very good thing, considering there is no tuning knob.
To band scan, you must use the #7 and #8 key on the keypad to increase and decrease frequency in predetermined steps. And, yes, the radio mutes between frequency changes.
You can also press and hold the #7 or #8 buttons to engage an auto-tune feature that finds the next strong signal.
The HR-11S’ rechargeable battery pack.
To input a frequency directly, simply press the enter button, key in the frequency, then press the enter button once more to engage that frequency. Very simple.
The volume up/down buttons are #1 and #2 on the keypad.
The keypad is not backlit and the layout for volume control, tuning, mode switching, etc., is a bit confusing; it doesn’t match any other radio I’ve ever used. Of course, with time you’ll master the keypad functions, but the design could be made more user-friendly.
Performance: setting expectations
SWLing Post community members know that I tend to review what I call “enthusiast grade” radios: receivers that perform well enough to attract the attention of DXers and dedicated listeners.
Self-powered radios, with few exceptions, rarely impress me in terms of performance. Indeed, some of the best that have been on the market have been analog units (I’m particularly fond of the Grundig FR200).
The Tivdio HR-11S is no exception––don’t expect to snag elusive DX with this unit. It’s not going to happen.
FM
The HR-11S is a capable FM receiver. Performance is on par with most average FM radios: you’ll easily receive all of your local broadcasters, but distant stations may require holding the unit in your hand, careful positioning, or adding an extra bit of wire to the antenna.
The FM audio is quite good via the HR-11S’s built-in speaker.
AM
The mediumwave, or AM broadcast band, is the HR-11S’ weakest suit. AM is plagued with internally-generated noises–especially in the lower part of the band–thus you’ll only be able to clearly receive local AM broadcasters that rise well above the noise floor. Thus I cannot recommend this radio for AM reception.
Shortwave
Shortwave reception is on par with other DSP self-powered radios I’ve tested. As I write this section of the review, I’m listening to China Radio International on 9,570 kHz in my office without even having the telescopic whip antenna extended. (CRI is a blowtorch station, however).
I find that the HR-11S can receive most strong broadcasters and even weaker stations, though the AGC is not ideal when fading is present.
If you’re seeking a self-powered radio with shortwave, the HR-11S is somewhat useful in this regard and is worth consideration.
Keep in mind, though, that an inexpensive dedicated ultralight shortwave radio like the Tecsun PL-310ET will perform circles around this unit.
Bluetooth
One feature I’ve found incredibly useful is the Bluetooth functionality. With Bluetooth mode engaged, you can connect the HR-11S to pretty much any mobile device and use it as a wireless portable external speaker. Since the speaker has decent audio fidelity for the size, and can be powered by battery, it’s a brilliant feature and will make watching videos on your smartphone, for example, that much better.
One negative? At least in my unit, I can hear some internally-generated noises in Bluetooth mode. This is especially noticeable at lower volume levels.
Recording
In full disclosure, I haven’t tested the recording functionality extensively. Built-in radio recording is an interesting feature, but one I would rarely use in a self-powered radio. I did make a handful of test recordings, however, and like many other DSP radios with a recording function, the HR-11S injects noise in the recordings.
Summary
Every radio has its pros and cons. When I begin a review of a radio, I take notes from the very beginning so that I don’t forget my initial impressions and observations. Here’s the Tivdio HR-11S pro/con list, from the first moments I turned it on to the present:
Pros:
Keypad entry
Great audio for size
Replaceable battery (Note: after unboxing unit, you must place battery in battery compartment; it’s packed in the side box)
Siren (see con)
Micro SD card for digital storage
USB can port audio from PC
Bluetooth––use as a portable wireless speaker for mobile devices (see con)
ATS (auto tune) function
Multiple power sources:
850mAh rechargeable lithium battery
hand-crank dynamo generator
Mini solar panel
DC 5V input (standard micro USB)
Backlit informative display
Customer service: Tivdio representatives seem to respond quickly to customer emails and comments on Amazon.com.
Cons:
Tuning is cumbersome (no tuning knob)
Mutes between frequencies
Siren too easy to activate, resulting in accidental activation
AM broadcast band (MW) is plagued with internally-generated noises
Keypad configuration is not intuitive and difficult to memorize for use at night or low light settings
Hand strap is very difficult to insert (hint: use a thin loop of wire to help thread it)
At low volume, noises can be heard in Bluetooth mode
Noises heard in recording function
Conclusion
Running an ATS scan on shortwave.
As I mentioned early in this review, I must set realistic expectations when reviewing self-powered radios. When most consumers consider a self-powered radio, they’re seeking a simple, basic radio that will provide information during times of need: power outages, natural disasters, or while hiking, camping, boating, or simply in an off-grid setting.
Internally-generated noises––especially on the AM band––will disappoint radio enthusiasts. If Tivdio could address this in future iterations of the HR-11S, it would substantially improve this unit.
My overall impression is that the HR-11S is chock-full of features, but none of them are terribly refined. There are even some internally-generated noises in Bluetooth mode, which really surprised me as it seems like an oversight by engineering.
I see the Tivdio HR-11S is a bit of a “Swiss Army Knife” of a self-powered radio. It has more functionality and connectivity than any other self-powered radio I’ve tested to date. Its features will, no doubt, appeal to the average consumer––and a quick look at Amazon reviews seem to support this theory. As a radio enthusiast, however, I would pass on the HR-11S until the internally-generated noises have been addressed.
For those who are interested, Tivdio passed along several coupon codes that SWLing Post readers can use to save money, should they decide to purchase the HR-11S:
Many thanks to SWLing Post contributor, Ivan Cholakov, who shares the following video where he compares the SDRplay RSP1A and the AirSpy HF+ software defined radios on shortwave and mediumwave:
Many thanks to SWLing Post contributor, Dan Robinson, who shares the following guest post:
ICOM’s IC-R8600: Can this mega-radio stay in the ring with big gun “legacy” receivers when it comes to shortwave band reception?
by Dan Robinson
When ICOM rolled out its new wideband receiver, the IC-R8600, I immediately took an interest in it. I have been primarily a hardcore DX’er and SWL and avoided purchasing wideband receivers, including the predecessor IC-R8500, because they were limited in areas such as selectivity.
My experience with ICOM includes owning a IC-R71A and R72, both of which I found to be strong performers, as well as a IC-R75. The R75 as everyone knows established a reputation as an excellent receiver that delivered bang for the buck, including for example 1hz readout and extreme stability.
In its design decisions with the 8600, ICOM clearly intended to hit it out of the park, taking a huge step from the 8500. That can be seen in the amazing color 4.3 inch LCD display with fairly fast spectrum scope and waterfall displays, coverage from 10 kHz to 3 gHz, decoding capability in multiple protocols, (Baudot RTTY, D-STAR™, NXDN™, dPMR™, DCR (Digital Communication Radio) and APCO P25, and the combination of SDR and superheterodyne circuitry, with 2000 memories.
The new Icom IC-8600 at the 2017 Hamvention
At this point, there have been numerous reviews of the 8600, and videos are all over YouTube showing the basics of its operation and features. It has numerous flexibilities selected from the front panel and within the menu system. The ability to record directly to SDHC cards eliminates the need to attach an external solid state recorder (over the course of my DX career I accumulated many of these). I can’t say enough about this capability which automatically keeps fully labeled logs.
Other features include ICOM’s wonderful Twin Passband Tuning, combined with the ability to adjust filters 1/2/3, adjustable attenuation, Digital AFC, tone controls, noise blanker digital noise reduction, speech enunciator, main tuning dial tension adjustment, synchronous L/U/Double sideband, adjustable panel brightness . . . in short, just about everything one would think should be included in a 21st century receiver of this kind, ICOM put in the 8600. The firmware update released recently (1.30) added the capability to use the radio’s IQ output with HDSDR software, which means that the receiver is now not only a standalone but also functions easily with a PC.
Since the 8600 has been on the market for some time now, I discussed with Thomas Witherspoon of SWLing Post, the idea of obtaining an 8600 for the specific purpose of comparing it to some of the top receivers in my collection.
JRC NRD-515
At the current time, that list includes a JRC NRD-545, the Drake R-8 (original version purchased in 1993), JRC NRD-515, Watkins Johnson 8718A/MFP, Cubic R-2411, and a McKay Dymek DR-33C. All of the radios in my shack use a Wellbrook 1530 loop, fed through a RF Systems DA-8 Distributor/Amplifier which maintains signal levels from all outputs.
Watkins Johnson 8718A/MFP
A surprising outcome of my comparisons of the 8600 to these radios is that my appreciation of the qualities of these older receivers was actually re-ignited–so much so that some that had been on my ‘to sell’ list are now back in the ‘keepers’ column. This is not as much a criticism of the 8600, as it is a reaffirmation of the quality that was built in to some of the great receivers of yesteryear.
Because my collection actually extends across 2 or 3 rooms, moving the 8600 away from my central receiver “stack” was not possible, so testing comparisons were limited to the sets mentioned above. I would have liked to compare the 8600 with, for example, some classic tube receivers (HQ-180A, Eddystone 830/7), but they have been mostly inactive and located away from incoming antenna inputs.
Here in Potomac, MD outside of Washington, DC, the addition of the Wellbrook a few years ago, after years suffering with long wires, fundamentally changed a difficult situation. Signals were boosted, noise reduced. I wish things had continued this way. Unfortunately about a year ago, my area began to be plagued by a troubling ignition-type buzz, source unknown, targeting 11,500 to 12,100 khz though noticed elsewhere in the shortwave bands. It has continued, usually worse in summer than in winter.
I begin with this to underscore what I noticed as a high point for the 8600: its Noise Blanker and digital noise reduction are in my opinion quite effective, so much so that when properly adjusted, they can eliminate troublesome ignition-type noise. While NR is useful, as noted in other reviews it needs to be used carefully so as not to introduce too much digital suppression.
Here is an example of NB and NR in use against severe ignition-type noise at my location:
In August of 2017, I had my first experience tuning a 8600 at a DXpedition in Ohio.
So, I had a basic grasp of the various controls — the A/B/C knobs, and the menu system. When I received my review unit from ICOM last November, I was up and running quickly, but still puzzled over some aspects of the receiver’s operation.
Thanks to Dave Zantow who alerted me to a possible issue involving firmware 1.30 which appeared to introduce an increase in audio harshness (ICOM has been alerted to this). Dave also had suggestions (see his full review of the 8600 and other receivers on his site) about audio adjustment and speakers, and tweaking of the front display to make maximum use of the Peak and Waterfall settings. Dave emphasizes that careful adjustment is required of the 8600’s tone controls and AGC decay settings to get the most out of the receiver.
Because it is among the receivers in my shack in close proximity to the 8600, I chose to perform a number of tests comparing the ICOM to the Japan Radio Company NRD-545. As everyone knows, the 545 was the last in JRC’s prosumer line of receivers. It is feature-rich — JRC threw everything into this receiver. But one issue followed JRC receivers through the 5xxxx series — noisy audio. After finally acquiring a 545 some years ago (a high serial number unit formerly owned by the late Don Jensen) I jumped on that bandwagon of criticisms about the 545’s audio. However, in terms of sensitivity and numerous tools to hear and process signals, the receiver remains among my favorites, and this remains the case after my comparisons with the 8600.
When I compared signals heard by the 8600 with the 545, I found that while the JRC does have that ‘DSP’ sound, it was in many situations actually clearer than the ICOM. That was the case even when following advice on adjusting the 8600’s tone controls and AGC. The following two videos compare the 545 and 8600 on 5,905 khz and 17,655 khz. A third shows the receivers on 6,040 khz demonstrating effectiveness of their notch filtering capabilities:
My next comparison was the Drake R8. Little can be said about the Drake R8xxxx series of receivers that hasn’t been said. That superb Drake audio, established with the R8 and continued through the R8B, puts these receivers at the top of the heap and makes stations stand out. So, it’s little surprise then when compared to the 8600, which is an SDR in the HF range up to 30 mhz or so, the R8 still sounded superior on many, though not all, stations. Use of the SYNC mode (not adjustable on the original R8, but was on the R8A/B) also improves recoverable detail on the Drake.
The following video shows the 8600, 545 and finally the R8 on 5,995 khz (Mali), and the three receivers compared on 9,650 khz (Guinea), and a third comparing the 8600 with the full range of receivers in my main receiver stack, tuned to 9,415 khz which at the time was China Radio International.
Despite what some critics have said, I believe that the 8600’s synchronous detection modes are actually pretty good, helping with fading and stabilizing signals. I think the ICOM’s sync is certainly superior to what I experienced with the IC-R75. I would rate the SYNC on the AOR 7030+ superior to the 8600, with the NRD-545 a bit behind the 8600.
Acquired about 2 years ago, my AOR-7030+ is a late serial number version of this fantastic receiver. If I were to sell every radio in my shack but 5, the 7030 would not leave. Put simply, it is among the top shortwave receivers ever made, with off-the-charts audio, and if one has the rare NB7030 card, amazing notch and other capabilities. Comparing the 7030 to almost any other shortwave receiver ever made is like putting a Ferrari on the track with the competition. The audio, and reception tools are just that good.
At the same time, in the 8600 ICOM has produced a receiver that has as many of the essential tools required to manipulate and clarify signals as exist. The twin passband tuning continues to be superb. Being able to vary bandwidth in conjunction with the PBT, and do so even in SYNC mode, further enhances reception powers. Combine this with the ability to actually see signals on the 8600’s beautiful color LCD — we’re getting pretty close to the ultimate receiver (though I would love for someone to drop the successor to ICOM’s IC-R9500 on my front doorstep).
The following videos compare the 8600 to the same full range of receivers, ending with the Watkins Johnson 8718A/MFP, all tuned to 5,935 khz, followed by a comparison of receivers tuned to 5,000 khz
In the following videos, I compare the 8600 to other receivers 11,810 khz (BBC) which shows
the superb audio of the Drake R8xxxx series, yet the 8600 does quite well, and another video
compares the 8600 with the 545 and R8 tuned to 6,070 khz.
In the months that I have had the 8600, I did some comparisons with other receivers, among them my Watkins Johnson 8718A/MFP, which you saw in several videos. WJs prior to the 8711/HF-1000s were built like boat anchors and are QUIET. WJ, Cubic and similar sets manufactured for government and intelligence agencies, shared superb sensitivity, and most cases, excellent audio.
Comparisons of the 8600 on shortwave frequencies had the so-called Premium radios out front. The ICOM clearly shined when it comes to modern signal processing and adjustment tools such as PBT, Notch, and infinitely variable selectivity.
Summary
So, here’s a summary of my impressions after weeks of testing the ICOM IC-R8600 against some of the top gun receivers of yesteryear.
The 8600 scores a 10 on reception tools that are useful — though not crucial in these days of waning shortwave broadcasting activity — in producing and processing listenable audio: Twin PBT, Notch and Auto-Notch, Variable Bandwidths (though limited at the high end to 10 kHz), Pre-Amp and Attenuation, and that beautiful color LCD that allows one to see signals.
Predictably, the 8600 doesn’t blow away premium receivers that were manufactured to pick up the signal equivalent of butterflies and targeted government and spy agencies, and it also does not out-perform a range of other classic receivers whose reputations are well-established.
From a sensitivity and audio perspective, there is no real competition with the Drake R8, which time and time again excels in producing superior easy-to-listen audio. And the same holds for the AOR 7030+.
JRC’s NRD-515 more than holds its own and in many cases exceeds the 8600 in signal sensitivity, and producing listenable audio, despite its selectivity limitations.
The NRD-545 — maligned by critics for its DSP audio, often produced highly-listenable audio even in comparison with the 8600. The ICOM and the 545 share features that provide tremendous flexibility, the tools required to slice and dice signals. If the JRC NRDxxx receivers were the modern equivalent of such boat anchor classics as the Hammarlund HQ-180A, the 8600 is certainly at the top of the heap when it comes to having those same tools in a 21st century receiver.
Audio Samples
I performed some additional audio only tests between the 8600 and NRD-545 on several frequencies. In each, I carouseled from wide to narrow on the 8600, and did the same on the NRD-545. Here are the results:
You may have noticed that while on some examples the 8600 appears to sound better, the 545, with DSP technology born in the 1990’s is more than competitive with the ICOM.
Conclusion
In conclusion, with the 8600 we have a receiver that tunes up to 3 gHz, with highly flexible color scope, usable with HDSDR, with every tool imaginable for sifting through signals from 10 kHz up to 30 MHz, which is the area I have focused on for decades.
ICOM’s superb Twin PBT knocks out interference and narrows the heck out of any signal, with highly adjustable notch capabilities, customizable bandwidth functions, and what I consider to be highly effective noise blanking and noise reduction. Add to this 2,000 memory channels, multiple antenna inputs, adjustable attenuation and AGC and you have far more than what is needed given the current state of shortwave broadcasting.
Here’s the tough question: Would I recommend that a shortwave listener focused on what remains of listening in the SW bands purchase a 8600? Or to put it another way: Is the 8600 that much of a better radio in the SW spectrum? The answer has to be no.
Numerous receivers from the classics to even the latest portables with multiple selectivity flexibility (see the XHDATA D-808 or Eton Satellit) work for that. The used market overflows with superb HF communications receivers. Any of the Drake R8xxx series receivers, available on the used market for $400 to $1,000, now constitute overkill when it comes to reception in the MW to 30 mHz range.
But if you can project someday to having the time and patience to apply yourself to what is available above 30 MHz, and have the appropriate antenna(s) for those ranges, then by all means, the 8600 is the radio for you. It is the Babe Ruth’s bat of the receiver world — AND it has numerous flexible tools (though one wishes that ICOM had included DRM capability).
As I finalized this review, I continued to wrestle with the decision of purchasing the 8600 that was so generously provided by ICOM. You won’t read here what my final decision was–but anyone who is interested can contact me in coming days and weeks to learn the answer.
Last minute update Just before this review went to press, I discovered an issue of concern: when the 8600 was left on overnight, or for any period of multiple hours, upon awakening from “sleep” (screen off) mode, nothing but distortion is heard from the speaker. The only solution was to perform a POWER OFF/POWER ON, after which normal audio was heard. This issue was I brought to the attention of ICOM.
I want to thank Ray Novak and Faheem Hussain of ICOM for providing the 8600 used in this comparison, and for their patience as I encountered several delays completing my review and getting to print. And thanks to Thomas Witherspoon without whose initial encouragement, this review would not have been possible.
Dan, thank you for an amazing IC-R8600 review and comparison with your benchmark commercial grade receivers! Thanks for taking the time to make thorough comparison video and audio recordings. Your guest posts are always most welcome on the SWLing Post!
Looking north toward Cape Lookout, Oregon, near the site of my SDR receiver recordings. Photo courtesy of Wikimedia Commons. In my original article 10 days ago, I set up a SWLing Post reader poll to let you give your opinion on which shortwave recordings within four pairs of audio files provided the most intelligible result. The recordings were intentionally noisy, low-level signals to help us discover–through critical listening to the files–if there is a clear favorite between the AirSpy HF+ or the Elad FDM-S2 receivers. Of course, there were only four pairs of recordings…not a very large sample size.
However, 34 readers of the original article took the time to listen and respond, so let’s get to the numbers, shown in these graphs:
Interestingly, the responses above seem to point to:
Two recording pairs tied in the results (50% / 50%) or were very close (HF+ 52.9% / FDM-S2 47.1%)
The FDM-S2 led one recording pair by a large margin (67.6% / 32.4%)
The HF+ led another recording pair by an equally large margin (67.6% / 32.4%)
Taken as a whole, no obvious winner emerged, although one might conclude the HF+ has a slight edge due to its lead in the “very close” recording pair of 7.230 MHz.
One thing is clear–the AirSpy HF+ is a surprisingly good performer for its price of $199 USD! For many enthusiasts this will be all the SDR they need.
As a final note, I’ll mention that the AirSpy HF+ used for the tests was totally stock. I have not yet performed the “R3 Bypass” mod nor the firmware update to my HF+ units. The simple R3 Bypass, discussed at length on the AirSpy Groups.io forum, significantly boosts sensitivity of the HF+ from longwave up to about 15 MHz, without any noted overload issues. For more on this modification from a MW DXer’s perspective, read Bjarne Mjelde’s insightful article at his Arctic DX Blog.
Thank you to all the readers who took the time to listen to the SDR recordings in this comparision and register your opinions.
Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington. He’s a regular contributor to the SWLing Post.
Many thanks to SWLing Post contributor, Ivan (NO2CW), who writes:
Hello, I posted on YouTube my review of the Sangean WFR-28 FM and Wifi Internet radio receiver.
In particular I was able to sideload my directory of English Language broadcast stations from over 100 countries using their “Favorites” menu. It now sounds like the good old days of shortwave …almost. I can listen to the morning traffic report in Singapore, local news from Guam, afternoon talk show from Gibraltar and a nighttime DJ from Uganda – all in English.
Of course, a number of personal assistant device like the Amazon Echo also stream radio via the TuneIn Radio aggregator, but since these devices rely on voice commands, some stations can be difficult to call up. I still prefer a proper WiFi radio/Internet appliance like the Sangean WFR-28 or Como Audio Solo.
I’m currently spending the better part of a week at Cape Lookout State Park on the Oregon coast, with a great view of the ocean through tall evergreen trees. This is one of my favorite parks in the Pacific Northwest, especially when DXing during the blustery winters from one of the nice cabins at Cape Lookout.
The view from the beach near my cabin; the turbulent waves were a precursor to the gale force winds at the park during the night of the 23rd!
https://youtu.be/EYUSU_gzgu4
Although I’m at the park for trans-Pacific medium wave DXing, I’m also comparing receivers, both SDRs and portables. This morning I sought out a few weak shortwave signals, pitting the Elad FDM-S2 SDR ($529 USD) against the AirSpy HF+ ($199 USD). I have a pair of the HF+ receivers to cover all of medium wave (as the FDM-S2 easily does). Many SWLing Post readers already know that the upstart HF+ trades bandwidth to gain high performance in order to keep the price reasonable.
My antenna used for the following recordings was a small “Flag” antenna using a Wellbrook Communications FLG100LN module and a 2K ohm variable potentiometer for termination. The design uses crossed tent poles in an “X” formation to support the wire loop. This design travels easily in a compact package; I have Dave Aichelman of Grants Pass, Oregon to thank for this very useful “tent pole loop” implementation of the Wellbrook FLG100LN.
The Wellbrook-based antenna functions superbly, and its low-noise design helps hold down QRM from the nearby cabins (which unfortunately have been “upgraded” recently with noisy cold fluorescent [CFL] light bulbs). The area around the Cape Lookout cabins used to be superbly low noise and suitable for radio listening, but now it is more of a challenge than before. The Wellbrook FLG100LN is perfect for the situation though; Wellbrook ALA1530LN Pro and ALA1530S+ 1-meter loop antennas work commendably at the park too.
The Wellbrook FLG100LN module with a home brew RFI choke in-line
A 2K ohm variable potentiometer is protected from the elements in a small plastic bag. The “pot” is adjusted for the best nulling of medium wave stations off the back side of the antenna’s reception pattern.
The “tent pole loop” antenna is strapped to a fence railing with ultra-strong Gorilla Tape to keep the 7-ft. square loop vertical.
On with the recordings…
For the FDM-S2 and HF+ comparisons I used the SDR-Console V3 software. Every parameter was identical for the receivers–sampling bandwidth, filter bandwidth, AGC, mode and so on.
Take a critical listen to the weak signals recorded with the SDR receivers, identified as only “Radio A” and “Radio B”.A link to a poll is at the end of this article;please indicate which recording of each pair has the most intelligible audio in your opinion, and submit your choices when you’ve made up your mind on each audio clip. After a week or so I’ll post the results of the voting, and identify the receivers.
9.615 MHz, LSB, Radio A
9.615 MHz, LSB, Radio B (note: the same male announcer heard in clip “A” begins at 00:14 in this “B” clip)
9.730 MHz, USB, Radio A
9.730 MHz, USB, Radio B
7.230 MHz, S-AM, Radio A
7.230 MHz, S-AM, Radio B
9.860 MHz, S-AM, Radio A
9.860 MHz, S-AM, Radio B
Note on 7.230 MHz recording: this was an interesting frequency, as the signal was tightly surrounded by a very strong local 40m ham radio LSB station as well as a strong China Radio International signal. There were other strong amateur and broadcast stations within 30-50 kHz of 7.230 MHz, also. This A-B test more than the others may indicate receiver performance in a strong RF environment on a crowded band.
Ready for the poll? Register your votes at the Google Docs form below:
In a week to 10 days I’ll post the results in another article. NOTE: I haven’t provided a “both sound the same” choice in the poll to encourage you to ‘dig deep’ into the audio and listen critically–to find something that stands out in one clip versus the other.
Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington. He’s a regular contributor to the SWLing Post.
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