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After SWling Post contributor, Guy Atkins, posted the survey results of his excellent Elad FDM-S2 vs AirSpy HF+ weak signal comparison, I received a few questions about the AirSpy HF+ “R3 Bypass” modification Guy mentioned in his post.
Guy has not yet performed the modification on his HF+–neither have I–but he points out that others have noted it: “significantly boosts sensitivity of the HF+ from longwave up to about 15 MHz, without any noted overload issues.”
I reached out to AirSpy president, Youssef Touil, for a little more insight about this modification. Youssef replied:
During the early phases of the design R3 was a place holder for a 0 ohms resistor that allows experimenters to customize the input impedance. For example:
A 300 pF capacitor will naturally filter the LW/MW bands for better performance in the HAM bands
A 10µH inductor would allow the use of electrically short antennas (E-Field probes) for MW and LW
A short (or high value capacitor) would get you the nominal 50 ohms impedance over the entire band, but then it’s the responsibility of the user to make sure his antenna has the right gain at the right band
A custom filter can also be inserted between the SMA and the tuner block if so desired.
Click to enlarge. (Photo source: RTL-S1DR.com)
R3 and the nearby resistors have been intentionally left outside of the RF shield, and their size was picked to be big enough to allow anyone to play with them. You will notice the size difference with the rest of the components.
In general, unless one knows what he’s doing, it’s not recommended to alter a working system. “If it’s working, don’t fix it”. But, we are hobbyists, and not doing so leaves an uncomfortable feeling of something unachieved. Most brands addressing the hobby market leave some tweaks and even label them in the PCB.
The main purpose of the HF+ is the best possible performance on HF at an affordable price. This is to incite HAMs to get started with this wonderful technology while using an SDR that isn’t worse than their existing analog rig.
The MW/LW/VLF crowd may have slightly different requirements, but that can be addressed by shorting a resistor.
Regards,
Youssef Touil
Thank you, Youssef, for replying to my inquiry so quickly and thoroughly.
No doubt, I too will eventually modify R3–it’s very difficult not to experiment, especially when a product was designed with the experimenter in mind.
I really feel like AirSpy has knocked it out of the ballpark with the HF+. For those of us primarily concerned with HF performance, this SDR is very hard to beat–especially at its $199 price point!
Our Texzon Wireless Power™ system allows the Earth itself to be used for clean, safe and efficient transfer of power between any two points on the globe, wirelessly. The system represents a paradigm shift in the science of electromagnetics.
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, G. Koopal, who who sent a tip regarding RTI’s French language service leaving shortwave. I followed up directly with RTI and received the following reply from their French language service team:
[English Translation]
We have just announced this news in the last “courriers des auditeurs” this Sunday, February 4th.
From March 25th, the French service and the Spanish service of RTI will unfortunately stop broadcasting on shortwave.
The schedule of programs will change a little but you can always listen to us on the new website that will be online very soon. More videos will be posted in the future. We have also opened a youtube channel where you can find all these videos!
Thank you for your question, see you soon.
The French service team of RTI
[Original French]
Nous venons tout juste d’annoncer cette nouvelle dans le dernier “courriers des auditeurs” de ce dimanche 4 février.
A partir du 25 Mars, le service français et le service espagnol de RTI cessera malheureusement de diffuser sur ondes courtes.
La grille des programmes va donc un peu changer mais vous pourrez toujours nous écouter sur le nouveau site internet qui sera en ligne très prochainement. Plus de vidéos seront postées à l’avenir. Nous avons d’ailleurs ouvert une chaîne youtube sur laquelle vous pourrez retrouver toutes ces vidéos !
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 Mark Stafford who shares the following news:
RIP Tom Taylor/ Barry Stephens a Short Wave Pirate Radio Legend
Just got some very bad news: Barry Stephens (Tom Taylor) of European Music Radio fame has died.
To many of us learning the art of Pirate Radio Broadcasting in the South East of England in the 1970’s, Tom was “The Governor”.
EMR was a class station, probably the best Short Wave Pirate in the late 70’s. Barry and his colleague Roger Tate were legends.
Tom/Barry was also a really nice guy who helped us so much. He fixed our transmitters so many times for us and taught us how important good modulation was. Tom used to tell us “you have got to have hissing sidebands, mate”! By that he meant, lots of top end so that it cut through the noise and splashed audio on the next door channel!
Tom had a famous three wheeler Reliant Robin that the he took the EMR gear out into the woods with! We will all remember that.
Thank you, Mark. Tom was an on the SWLing Post readers and even sent his EMR weekend notes which I happily published. Though I never got to meet him in real life, he was always a good soul–and of course, a tremendous figure in the world of shortwave pirate radio.
Rest in peace, Tom.
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After SWling Post contributor, Guy Atkins, posted the survey results of his excellent Elad FDM-S2 vs AirSpy HF+ weak signal comparison, I received a few questions about the AirSpy HF+ “R3 Bypass” modification Guy mentioned in his post.
