Before I had even taken delivery of the new Icom IC-705 transceiver, a number of SWLing Post readers asked me to do a series of blind audio comparison tests like I’ve done in the past (click here for an example).
Last week, I published a series of five audio tests/surveys and asked for your vote and comments. The survey response far exceeded anything I would have anticipated.
We received a total of 931 survey entries/votes which only highlights how much you enjoy this sort of receiver test.
In this challenge, I didn’t even give you the luxury of knowing the other radios I used in each comparison, so let’s take a look…
Since the Icom IC-705 is essentially a tabletop SDR, I compared it with a couple dedicated PC-connected SDRs.
WinRadio Excalibur SDR
The WinRadio Excalibur
I consider the WinRadio Excalibur to be a benchmark sub $1000 HF, mediumwave, and longwave SDR.
It is still my staple receiver for making off-air audio and spectrum recordings, and is always hooked up to an antenna and ready to record.
In the tests where I employed the WinRadio Excalibur, I used its proprietary SDR application to directly make recordings. I used none of its advanced filters, AGC control, or synchronous detection.
I also consider the Airspy HF+ SDR to be one of the finest sub-$200 HF SDRs on the market.
The HF+ is a choice SDR for DXing. Mine has not been modified in any way to increase its performance or sensitivity.
In the test where I employed the HF+ I used Airspy’s own SDR application, SDR#, to directly make recordings. I used none of its advanced filters, AGC control, noise reduction, or synchronous detection.
If you check out Rob Sherwood’s receiver test data table which is sorted by third-order dynamic range narrow spaced, you’ll see that the KX3 is one of the top performers on the list even when compared with radios many times its price. Due to my recording limitations (see below) the KX3 was the only other transceiver used in this comparison.
Herein lies a HUGE caveat:
The WinRadio application
As I’ve stated in SDR reviews in the past, it is incredibly difficult comparing anything with PC-connected SDRs because they can be configured on such a granular level.
When making a blind audio test with a stand-alone SDR radio like the IC-705–which has less configurability–you’re forced to take one of at least two paths:
Tweak the PC-connected SDR until you believe you’ve found the best possible reception audio scenario and use that configuration as a point of comparison, or
Attempt to keep the configuration as basic as possible, setting filters widths, AGC to be comparable and turning off all other optional enhancements (like synchronous detection, noise reduction, and advanced audio filtering to name a few).
I chose the latter path in this comparison which essentially undermines our PC-connected SDRs. Although flawed, I chose this approach to keep the comparison as simple as possible.
While the IC-705 has way more filter and audio adjustments than legacy transceivers, it only has a tiny fraction of those available to PC-connected SDRs. Indeed, the HF+ SDR, for example, can actually be used by multiple SDR applications, all with their own DSP and feature sets.
In short: don’t be fooled into thinking this is an apples-to-apples comparison. It is, at best, a decent attempt at giving future IC-705 owners a chance to hear how it compares in real-word live signals.
The Zoom H2N connected to my Elecraft KX2.
Another limiting factor is that I only have one stand-alone digital audio recorder: the Zoom H2N. [Although inspired by Matt’s multi-track comparison reviews, I plan to upgrade my gear soon.]
The IC-705 has built-in digital audio recording and this is what I used in each test.
The WinRadio Excalibur and Airspy HF+ also have native audio recording via their PC-based applications.
With only one stand-alone recorder, I wasn’t able to simultaneously compare the IC-705 with more than one other stand-alone receiver/transceiver at a time.
As I mentioned in each test, the audio levels were not consistent and required the listener to adjust their volume control. Since the IC-705, Excalibur, and HF+ all have native recording features, the audio levels were set by their software. I didn’t post-process them.
Blind Audio Survey Results
With all of those caveats and disclaimers out of the way, let’s take a look at the survey results.
Blind audio test #1: 40 meters SSB
In this first test we listened to the IC-705, WinRadio Excalibur, and Belka-DSP tuned to a weak 40 meter station in lower sideband (LSB) mode. Specifically, this was ham radio operator W3JPH activating Shikellamy State Park in Pennsylvania for the Parks On The Air program. I chose this test because it included a weak station calling CQ and both weak and strong stations replying. There are also adjacent signals which (in some recordings) bleed over into the audio.
Radio A: The Belka-DSP
Radio B: The WinRadio Excalibur
Radio C: The Icom IC-705
The Icom IC-705 was the clear choice here.
Based on your comments, those who chose the IC-705 felt that the weak signal audio was more intelligible and that signals “popped out” a bit more. Many noted, however, that the audio sounded “tinny.”
A number of you felt it was a toss-up between The IC-705 and the Belka-DSP. And those who chose the WinRadio Excalibur were adamant that is was the best choice.
The WinRadio audio was popping in the recording, but it was how the application recorded it natively, so I didn’t attempt to change it.
Test #2: 40 meters CW
In this second test we listened to the Icom IC-705 and the Elecraft KX3 tuned to a 40 meter CW station.
Radio A: Icom IC-705
Radio B: Elecraft KX3
The Elecraft KX3 was preferred by more than half of you.
Based on your comments, those who chose the KX3 felt the audio was clearer and signals had more “punch.” They felt the audio was easier on the ears as well, thus ideal for long contests.
Those who chose the IC-705, though, preferred the narrower sounding audio and felt the KX3 was too bass heavy.
Test #3: Shannon Volmet SSB
In this third test we listened to the Icom IC-705 and WinRadio Excalibur, tuned to Shannon Volmet on 8,957 kHz.
Radio A: WinRadio Excalibur
Radio B: Icom IC-705
The Icom-705 audio was preferred by a healthy margin. I believe, again, this was influenced by the audio pops heard in the WinRadio recording (based on your comments).
The IC-705 audio was very pleasant and smooth according to respondents and they felt the signal-to-noise ratio was better.
However, a number of comments noted that the female voice in the recording was actually stronger on the WinRadio Excalibur and more intelligible during moments of fading.
Test #4: Voice of Greece 9,420 kHz
In this fourth test we listen to the Icom IC-705, and the WinRadio Excalibur again, tuned to the Voice of Greece on 9,420 kHz.
Radio A: Icom IC-705
Radio B: WinRadio Excalibur
While the preference was for the IC-705’s audio (Radio A), this test was very interesting because those who chose the Excalibur had quite a strong preference for it, saying that it would be the best for DXing and had a more stable AGC response. In the end, 62.6% of 131 people felt the IC-705’s audio had slightly less background noise.
Test #5: Radio Exterior de España 9,690 kHz
In this fifth test we listened to the Icom IC-705, and AirSpy HF+, tuned to Radio Exterior de España on 9,690 kHz. I picked REE, in this case, because it is a blowtorch station and I could take advantage of the IC-705’s maximum AM filter width of 10 kHz.
Radio A: Icom IC-705
Radio B: Airspy HF+
The IC-705 was preferred by 79% of you in this test.
Again, very interesting comments, though. Those who preferred the IC-705 felt the audio simply sounded better and had “punch.” Those who preferred B felt it was more sensitive and could hear more nuances in the broadcaster voices.
So what’s the point of these blind audio tests?
Notice I never called any radio a “winner.”
The test here is flawed in that audio levels and EQ aren’t the same, the settings aren’t identical, and even the filters have slightly different shapes and characteristics.
In other words, these aren’t lab conditions.
I felt the most accurate comparison, in terms of performance, was the 40M CW test with the KX3 because both employed similar narrow filters and both, being QRP transceivers, are truly designed to perform well here.
I essentially crippled the WinRadio Excalibur and Airspy HF+ by turning off all all but the most basic filter and AGC settings. If I tweaked both of those SDRs for optimal performance and signal intelligibility, I’m positive they would have been the preferred choices (indeed, I might just do another blind audio test to prove my point here).
With that said, I think we can agree that the IC-705 has brilliant audio characteristics.
I’ve noticed this in the field as well. I’m incredibly pleased with the IC-705’s performance and versatility. I’ll be very interested to see how it soon rates among the other transceivers in Rob Sherwood’s test data.
The IC-705 can actually be tailored much further by adjusting filter shapes/skirts, employing twin passband tuning and even using its noise reduction feature.
If anything, my hope is that these blind audio tests give those who are considering the Icom IC-705 a good idea of how its audio and receiver performs in real-word listening conditions.
In September we began of our three-part Primer on Software-Defined Radios (SDRs). Part One (September)focused on the nomenclature and components of a functioning SDR system; Part Two (October) took a look at some affordable SDR station options that will propel you into the world of SDRs for less than $200 US. This month, in Part Three––our final installation––we’ll dive a little deeper into the SDR rabbit hole, and investigate higher-end SDRs as well as ham radio transceivers with embedded SDRs.
Investing in SDR hardware
As we mentioned in Part 2 of our primer, gaining entry into the world of SDRs can be quite affordable. With merely $200 or less, you can fully explore the radio spectrum with an SDR that has truly excellent performance characteristics.
So, why would you pay more?
Let’s consider this. If, say, you happen to live in an RF-dense environment, such as a busy city, if you live near strong broadcaster(s), and/or if you’re a DXer who’s seeking benchmark performance, then you might wish to devote a little more of your cash to your SDR hardware.
When you pay more for an SDR, the additional cost is typically going toward the hardware rather than the software. Indeed, my favorite SDR (software) applications are absolutely free, and pair with a number of benchmark SDRs. But good hardware is vital to performance. The lineup of SDRs––that is, the receiver hardware––discussed below typically has better filtering, preselectors, shielding, and receiver architecture focused on HF performance. They also tend to offer a more robust front end, lower noise floor, and better dynamic range. All of this, of course, results in better performance overall. Some of these SDRs also offer unique specialty features, like built-in web servers.
The following SDRs are carefully hand selected, and in my view, represent a balance between price and performance. And again, this is by no means a comprehensive list; it’s simply a selection of what you’ll find currently available on the SDR market.
So, without further ado, we’ll begin our discussion with “black box” SDRs, then move on to SDR transceivers and transceivers with embedded SDRs.
The SDRplay RSPduo
In May of this year (2018), the UK-based SDR designer and manufacturer SDRplay released their latest receiver: the SDRplay RSPduo.
What sets this little black box apart from the competition is just what its name implies: the duo is a dual tuner SDR. In other words, it’s two independent SDRs rolled into one.
Being the price leader in the world of SDRs, SDRplay retails the RSPduo for $279.95. And, I must add, it’s a true bargain for a feature-packed 14-bit high-performance device.
The RSPduo’s tuners can operate individually, anywhere between 1kHz and 2GHz, with up to 10MHz of working bandwidth. You could also set up the RSPduo so that both tuners can operate simultaneously, again between 1kHz and 2GHz, with up to 2MHz of bandwidth per tuner. The RSPduo has a high-stability reference along with external clocking features which makes this SDR an affordable option for industrial, scientific, as well as educational applications. It’s housed in a quality steel enclosure.
SDRplay’s development team is already working on new features such as true diversity reception, which will be included as a free upgrade to their popular SDRuno proprietary application.
To be clear, there is no other sub-$300 SDR on the market that currently has true dual-tuner functionality. Thus, the RSPduo is a good value, in my opinion––and an inexpensive upgrade to a proper dual-receiver SDR––so if this is something you’d like to add to your shack, go ahead! Bite the bullet, and acquire an RSPduo. Likely you won’t regret it.
Like the RSPduo, the KiwiSDR has a unique feature that makes it stand out among the other receivers mentioned here: it is designed to be fully controlled via a web-browser-based SDR application. Not only can you use your KiwiSDR locally, but you can share it with the world via the KiwiSDR network. You can configure the KiwiSDR to allow up to eight simultaneous guest users, assuming only that you have access to the modest amount of Internet bandwidth this requires.
The KiwiSDR is available in two versions: the SDR cape, alone, and a more complete version which includes the SDR cape, BeagleBone computer, enclosure, and GPS antenna. Both versions include all SDR software loaded on a micro-SD card.
Although the KiwiSDR might sound like an experimenter’s receiver since it requires a degree of assembly and configuration––at least, a bit more so than the other units I review here––it’s actually fairly simple to assemble, install, and put on the air. In fact, the only challenge that you might face is that of setting up your router for global access to your KiwiSDR. It does require either a static IP address or (more commonly) an IP address forwarding service. Check out the support documentation in advance to make sure your Internet connection will work.
The KiwiSDR covers from 10 kHz to 30 MHz, thus is not a wideband receiver like the SDRduo. Like the SDRs that follow, it focuses its performance on HF and lower bands.
I find it incredible that for just $299 US, you can purchase the full KiwiSDR kit––one that includes everything you need to put your SDR on the air and online. Because of this, I believe the KiwiSDR has become the dominant web SDR platform currently on the market. Perhaps this remarkable fact overshadows the fact that the KiwiSDR is also a superb performer, touting a brilliant dynamic range as well as overall excellent sensitivity and selectivity.
As my friend and fellow radio listener Mark Fahey, an early adopter of the KiwiSDR, is quick to point out, the KIwiSDR is unique in that it doesn’t connect to a PC or other computer to operate. It’s a stand-alone: just connect an antenna, DC supply, and network cable, then you’re ready to go. All of the “work” is delivered by the piggyback BeagleBone CPU.
What’s not to love? While the web-based SDR application is full-featured, it does lack spectrum recording and some other advanced controls. This is due to the relatively modest processing power of the onboard CPU. That said, The KiwiSDR application does contain features/functionality via extensions that are fairly impressive.
Additionally, when updates are rolled out for the KiwiSDr application, these take effect globally. Only recently, for example, audio recording and amazing TDoA (Time Distance of Arrival) functionality were added.
Oh, and one more thing before we move on: the KiwiSDR is the only SDR I know that is exclusively controlled by a web-based SDR application for both the online guest and the local user/owner. There is no separate downloadable application. Thus, whether you’re using your own local KiwiSDR or an online SDR, the user experience is exactly the same. It’s seamless and user-friendly…just as it should be.
Want to try the KiwiSDR before purchasing? Easy! You can browse and select any one of two hundred KiwiSDRs online on SDR.hu.
Italian-based SDR manufacturer, ELAD, has built a solid reputation over the years for truly pushing the SDR performance envelope in the $500-$1000 market.
I have owned their Elad FDM-S2 for four years now (check out my full review in the November 2014 issue of The Spectrum Monitor). The FDM-S2 continues to impress and to hold its own among more recent competitors––a true indication of excellent engineering and hardware.
The FDM-S2’s frequency coverage is 9 kHz-52 MHz, 74-108 MHz, and 135-160 MHz. I should note here that besides being a great HF and mediumwave performer, the FDM-S2 is an FM DXer’s choice receiver; FM performance on this rig is just superb.
ELAD supports all of their SDRs with their own proprietary application which, of course, is designed to take full advantage of the SDR’s available performance. The ELAD application is feature-packed and even includes built-in DRM decoding. Interestingly, it will allow the FDM-S2 to be used as two completely independent tuners in “double DDC mode”––the working bandwidth of each tuner, in this case, is 384 kHz, and each can be placed within one of the FDM-S2’s input ranges.
In truth, I like pairing my FDM-S2 with the excellent (and free) SDR Console SDR application; I prefer its user interface and recording functionality over the ELAD application.
If you live in an RF-dense area, you might consider one of ELADs external pre-selection filter systems to keep the FDM-S2 from overloading in the presence of very strong signals.
Photo of the new ELAD FDM-S3 from the 2018 Hamvention
Note that ELAD will soon be releasing the newest addition to their product line: the FDM-S3. I know very little about the FDM-S3, but I do know ELAD is promising groundbreaking performance and dynamic range, setting a new benchmark for the $1000 price bracket. We do know the FDM-S3’s processing bandwidth is an impressive 24.576 MHz––wide enough to include the entire FM broadcast band!
I’m not sure if FM DXers will be able to take advantage of spectrum recording at a 24 MHz bandwidth, because I suspect it could push 24GB of data per minute. The FDM-S3 may well keep up, but I’m not sure the typical computer hardware can handle that kind of data transfer…it may be likened to, in radio terms, drinking from the proverbial fire hose!
However: ELAD will be sending me a loaner FDM-S3 to review in the coming months, so stay tuned for more on this DXer’s dream rig!
The current FDM-S3 price, by the way, is 949.90 EUR.
The WinRadio Excalibur
My first foray into the world of benchmark SDRs was made with the Australian-made WinRadio WR-G31DDC Excalibur. And although this SDR has been on the market for the better part of a decade, it still outperforms many of its competitors.The Excalibur’s frequency range is 9 kHz to 49.995 MHz, providing absolutely stellar performance across the spectrum.
It’s a favorite SDR in my radio shack, despite the fact that it can only be fully controlled by WinRadio’s own proprietary SDR application (at least, I know of no other compatible applications). On the plus side, the WinRadio application is one of my favorites.
The application’s file size is extremely compact––only a 9MB download. The user interface is logical, ergonomic, and responsive. Other than SDR Console, it has some of the best recording functionality available today.
I’ve logged more airtime with the Excalibur than with any other SDR I own, mainly because of its superb overall performance, responsive application, and recording functionality. I use the Excalibur as a benchmark for receiver evaluations and find that very few can match its solid performance.
The WinRadio Excalibur can be purchased through a number of distributors worldwide for about $950.
Enablia TitanSDR Pro
The Enablia Titan SDR Pro is an outlier product in our SDR Primer series, in that it retails in excess of $2,000. However, it’s the highest performing SDR I’ve ever tested. Serious weak-signal DXers will likely be quite pleased with this rig.
And speaking as a radio archivist, the Titan has the most powerful set of audio and spectrum recording features I’ve used, to date. Selectable spectrum recordings can be made from within the wide working bandwidth, and it can run up to four fully-independent SDR receivers, simultaneously.
The Titan comes with 16 frequency preselectors onboard, and a 9 kHz to 32 MHz frequency coverage. Its front end is simply bullet-proof, and thus could be operated in a demanding RF environment.
The TitanSDR ships with a brilliant proprietary application. It’s designed to make managing the Titan’s multiple virtual receivers and four independent SDR receivers as straightforward (and easy!) as possible. As I said in my review, Enablia engineers quite successfully accomplished this. The only downside is that only the TitanSDR application can run only the TitanSDR; no other third-party apps work with it. In addition, when making spectrum recordings, the file format is unique and the header information is actually stored in a separate file. This means when you are transferring a set of spectrum recordings, the header file must also be accounted for.
Of course, there is the daunting price tag of the TitanSDR, which makes it clear that this was a receiver designed for government and commercial use, in particular, for signal intelligence. Thus it’s likely no surprise that the basic version of the TitanSDR retails for 1380 EUR, the TitanSDR Pro for an even heftier 1970 EUR.
To be fair, there are not many readers who would consider the TitanSDR Pro, but I thought it worth mentioning as it demonstrates a clear case of hardware becoming an innovation’s primary focus.
The SDRs above represent merely a small slice of SDR market availability. There are several other notable manufacturers and SDRs worth considering, thus worth noting.
The Bonito Radiojet 1309 Plus
Germany-based Bonito manufactures a number of SDRs, antennas and components that are highly regarded among DXers. Bonito’s “hybrid” SDRs pack a lot of performance yet require very little in terms of computer resources. Their latest SDR, the Bonito RadioJet 1309 Plus covers 0.02 MHz to 1600 MHz with a spectrum display that can be widened to 3.2 MHz. I have not personally evaluated the RadioJet 1309 Plus, but I did review an early version of the RadioJet (the 1102S) that lacked the additional IQ-receiver of the 1309. I found it an impressively sensitive and selective receiver with excellent audio characteristics. Click here to read that review.
The RFspace Cloud-IQ
RF Space has been manufacturing SDRs longer than many other manufacturers, and the company offers a number of products, including the SDR-IQ, the NetSDR+, the Cloud-IQ, and––soon to come––the CloudSDR.
In Part 2 of our primer, we mentioned the AirSpy HF+ which packs impressive HF performance. Airspyalso manufactures the Airspy R2 and Spyverter R2–this $218 US combination produces a compact SDR package with excellent dynamic range and superb frequency stability.
I’m also fond of the classic Microtelecom Perseus SDR, which I’ve seen sold used for approximately $700 US. WinRadio, too, offers higher-end SDRs with a wider frequency range and working bandwidth than the Excalibur––so if your budget allows, you might consider these.
Regardless, keep in mind that if you want to use your monetary resources efficiently, there is no need to splurge for higher-end SDRs unless your use and application demands increased performance. Before you pull the trigger to buy such a rig, I would simply take into consideration the unit’s frequency range, working bandwidth, and performance characteristics, as well as taking the time to read plenty of user reviews. This increases the odds that you’ll get just what you want.
So far, I’ve only mentioned SDR receivers in this primer, but there is a healthy selection of “black box” type SDR transceivers on the market, as well. By “black box,” I mean the transceiver itself (all of the hardware) housed in a box––with, of course, the relevant ports for antennas, data, power, mics, CW keys, and a number of peripherals. These SDRs almost always require a computer for operation, although lately manufacturers are beginning to offer optional touch-screen front panels which can bypass the need for external computer operation.
Unlike the world of tabletop radios, where it might be less expensive to invest in a general coverage transceiver rather than a dedicated receiver, SDR transceivers almost always cost more than an equivalent SDR receiver.
Also note that SDR transceiver applications do not always include audio and spectrum recording functions. In addition, their working bandwidth might be more narrow that other receive-only SDRs, although they may offer more virtual receivers and spectrum “slices.”
Finally, SDR transceiver applications tend to be proprietary; when you purchase the transceiver, you’re also likely receiving the only SDR application that will interface with it. Hypothetically, if you purchase an SDR transceiver and the company that produced it goes under, you might have issues when the application is no longer updated with operating system upgrades and iterations. The lesson here is that I believe you should try to stick with the healthiest companies and those with solid, large user bases. This increases the likelihood that the application will be supported in the future.
Low-cost, low power SDRs for the experimenter
We’ll start with the least expensive SDR transceivers designed with the experimenter in mind, that can, with a little adaptation, also be employed by ham radio operators as very low-power transceivers.
The HackRF One ($299) by Great Scott Gadgets is an excellent SDR. It has an incredibly wide frequency range (1 MHz to 6 GHz), and can transmit anywhere from 3 mW to 30 mW depending on the frequency. That’s flea power, true, but if your goal is to experiment in your local surroundings, it’s typically more than enough output. The HackRF is open-source and sports a large user community that have employed it in dozens of applications. The HackRF was one of the first SDRs to really give experimenters a full tool set to manipulate the world of wireless.
The LimeSDR ($299) is another crowd-funded project that has been incredibly popular. Like the HackRF, it is a low-cost, open-source SDR platform that can be used to support just about any type of wireless communication standard. What makes the LimeSDR unique is that it is integrated with a Snappy Ubuntu Core, which means users can simply install applications from an app store to increase functionality. As LimeSDR states, their platform “gives students, inventors, and developers an intelligent and flexible device for manipulating wireless signals, so they can learn, experiment, and develop with freedom from limited functionality and expensive proprietary devices.
Again, only consider the HackRF of LimeSDR if your main goal is to experiment with the world of wireless. If you’re looking for a full-featured SDR transceiver intended for ham radio, read on.
Ham Radio SDR Transceivers
The Flex Radio booth at the 2018 Hamvention.
Without a doubt, the dominant name in the world of US ham radio transceivers is Texas-based Flex Radio. Flex has been around since the very earliest days of SDR transceivers and has produced a wide variety of high-performance rigs. In recent years, their product development and production has focused on higher-end transceivers with the discerning DXer and contester in mind. Their signature series SDRs pack incredible performance, yet can be operated from modest PCs since most of the processing horsepower and hardware are all within the radio chassis. Flex has also developed a fully wireless touch-screen Maestro Control Console that can be used over a local network, or even the Internet, to seamlessly control a remotely-connected Flex SDR. Flex Radio SDRs can cost anywhere from $2,000 – $7,500 US.
“One of Flex’s newest models, the Flex-6600, includes 7th Order Contest Band Bandpass Filters and dual Analog to Digital Converters. Which means that, using this radio, one can listen on one band while transmitting on another. Contesters call this ‘Single Operator Two Radio’ operation, and if you can do it successfully, it leads to big contest scores. Having this functionality in one box, without additional controllers and interfaces, is remarkable.”
Two other SDR transceiver manufacturers with large user bases are the Sweden-based SunSDR and India-based Apache Labs. Both companies produce high-performance SDRs and, like Flex, set benchmarks in terms of transceiver performance. I will not comment at length about either company because I’ve not had the opportunity of personally testing their products, but I encourage you to search online reviews about their products.
Tabletop SDR transceivers
The Elad FDM-DUO transceiver is both a stand-alone tabletop and fully-functioning SDR when paired with a PC.
There are a number of full-featured tabletop SDR transceivers on the market. One of the first SDR manufacturers to build a fully self-contained tabletop model with PC integration was ELAD, with their FDM-DUO QRP transceiver. Tabletop SDRs at the time of the FDM-DUO’s release were very limited in their functionality when connected to a PC. Some of them had stripped-down applications and lacked features like spectrum recording and multiple virtual receivers. The FDM-DUO, when connected to a PC running ELAD’s software, gives the user full control of the SDR. Indeed, the experience is identical to that of using the FDM-S2 mentioned above, however the DUO is also a transceiver. Since the DUO’s release, other SDR manufacturers have designed models with full SDR application integration.
The Flex 6600M is a handsome standalone SDR transceiver.
Recently, Flex Radio introduced their Flex “M” Signature Series SDR Transceiver. These tabletop SDRs can be configured with most of the SDR receivers Flex currently produces. Their displays are impressive and useful; indeed, the spectrum waterfall resolution and size is one of the best I’ve seen on a tabletop transceiver. The front panel is large and sports a number of controls, the design harkening back to large contest-grade transceivers like the Ten-Tec OMNI VII and Orion series.
The SunSDR MB1 at the 2018 Hamvention.
This year at the Hamvention in Xenia, OH, I had a chance to check out the SunSDR MB1. Like the Flex M series, the MB1 sports a comprehensive front panel and an amazing assortment of connections on the back panel. As I took a tour of this radio––and it really did require a tour, it’s so densely feature-packed––I was most impressed by the thought that went into this stand-alone SDR transceiver. I love the front panel display, graphics, and overall ergonomics. I understand it will also deliver benchmark performance; indeed with prices starting at a steep $7,000 US, I would expect nothing less!
SDR transceiver summary
As we’ve pointed out in this part of our primer, pure SDR transceivers are a product for radio operators willing to invest more financially in order to take advantage of the advanced functionality and performance a true SDR can provide. At present there are surprisingly few players in the pure SDR transceiver market; this is a product category ripe for expansion. And as more manufacturers get into the game, I believe competition will direct prices into even more affordable territory.
Transceivers based upon SDR technology
The final category we’ll discuss is transceivers based upon SDR technology. It’s a sign of the times, indicating the direction that all enthusiast-grade transceivers and receivers are likely heading.
The Icom IC-7300 transceiver
Because the fact is, whether or not you feel inclined to embrace SDRs in your radio world, you may be surprised that you already have: for many years now, radio manufacturers have built their transceivers and receivers on SDR and I/Q quadrature down-sampling technology. All of the transceivers introduced in the past few years that sport on-board spectrum displays––like the Icom-IC7300, Icom IC-7610, and the new Yaesu FT-DX101D––are, of course, based on SDR technology.
Many others, like the Elecraft KX3 and KX2, which look much more like a traditional radio, are also based on SDR architecture. Indeed, almost all of the major manufacturers implement SDR technology in their current product lines. Manufacturers have caught on, learning how to leverage SDR technology in a way that maximizes receiver performance while keeping the overall price more affordable than comparably-performing legacy radios of former days.
Yet while these radios are SDRs at their core, they often are limited in their functionality when connected to a PC; most can be completely controlled by a PC and many can even export their I/Q data, but usually they won’t offer the working bandwidth and the advanced functionality of a true SDR transceiver.
If I’ve piqued your curiosity about the world of SDRs, and have yet to add one to your shack, I would encourage you to invest in an SDR receiver––at the very least, in one of the affordable rigs mentioned in Part 2 of this series.
Speaking for myself, I was once a “knobs and buttons” radio operator who thought I’d never want to control a radio through a computer and monitor. But when I hesitantly invested in my first SDR, I found it eye-opening––not to mention somewhat democratizing, in that it sets all radio listeners on the same level, as the spectrum becomes visually understandable, and thus accessible, to all who encounter it. I found that if you love to listen, also being able to look at your audio, especially when editing or archiving, but any time you’re tuning around through the spectrum, just clarifies and enhances your overall radio experience. I soon became hooked…and have never looked back.
Now, I can assure you, I’ll never again be without an SDR. The ability to visualize our radio spectrum via SDR’s virtual window is truly illuminative. What’s more, I’d even venture to speculate that you may share in finding the experience, if you’ll forgive the colloquialism, pretty darn cool.
I’ve owned my Elecraft KX3 for five years, and this little rig continues to amaze me.
In 2013, I gave the KX3 one of the most favorable reviews I’ve ever published–and it continues to hold its own. That’s why last year I recommended the KX3 to my buddy and newly minted ham radio operator, Sébastien (VA2SLW), who had already been eyeing the KX3 as his first HF transceiver.
A few weeks ago, Sébastien bit the bullet and is now the proud owner of a KX3 with built-in ATU. He purchased the KX3 with plans to do a lot of field operations including SOTA (Summits On The Air) and also use the KX3 at home.
Wednesday, I popped by Sébastien’s flat to help sort through some low-profile antenna options. I had suggested that he not invest in a factory made antenna just yet, but instead explore what he’s able to do with a simple wire antenna directly connected to the KX3 with a BNC Male to Stackable Binding Posts adapter. I’ve had excellent luck using this simple arrangement this in the past with the KX3, KX2 and even the KX1.
I did a quick QRM/RFI survey of his flat and balcony with my CC Skywave SSB. While there were the typical radio noises indoors, his balcony was pleasantly RFI quiet. At 14:00 local, I was able to receive the Voice of Greece (9,420 kHz), Radio Guinée (9,650 kHz) and WWV (both 10,000 and 15,000 kHz) with little difficulty. His building has incredibly thick concrete walls–I assume this does a fine job of keeping the RFI indoors. Lucky guy!
We popped by a wonderfully-stocked electronics shop in Québec City (Électromike–which I highly recommend) picked up some banana plugs and about 100′ of jacketed wire. We took these items back to the flat and cut a 35′ length of wire for the radiator and about 28′ for the ground. We added the banana plugs to the ends of each wire.
Sébastien temporarily attached one end of the antenna wire to the top of the fire escape and we simply deployed the ground wire off the side of the balcony. Neither of these wires interfere with his neighbors and neither are close to electric lines.
I had planned to cut both the radiator and ground until we found the “sweet spot”: where the ATU could find matches on 40, 30, 20 and 17 meters (at least).
Much to my amazement, the KX3 ATU got 1:1 matches on all of those bands save 80M where it still could achieve a 2.8:1 ratio. I couldn’t believe it!
Frankly, Elecraft ATUs are nothing short of amazing.
Even the ATU in my little KX2 once tuned a 20 meter hex beam to 40 meters and found a 1:1 match to boot. In contrast, the Icom IC-7300 sitting next to the KX2 wasn’t able to match that hex beam even though we performed a persistent ATU search. Not surprising as I wouldn’t expect a 40 meter match on a 20 meter antenna, but the Elecraft ATU did it with relative ease.
Sébastian did a quick scan of the ham radio bands where we heard a number of EU stations. I also took the opportunity to point out how well the KX3 operates as a broadcast receiver with the AM filter wide open and using headphones in the “delay” audio effects mode. The Voice of Greece sounded like a local station–absolutely gorgeous signal.
It was getting late in the day, so I couldn’t hang around to call CQ with Séb, but I left knowing that he is going to have a blast playing radio at home and, especially, in the field. Next, he plans to build a simple mag loop antenna, get a BioEnno LiFePo battery and eventually add other Elecraft accessories to his station. I’d say he’s off to a great start!
This unit works beautifully with both my old and new iPhone headsets. The combination of the headset and this adapter take a tiny amount of space in my go-bag. Audio reports are great, even with speech compression set to max (MENU:TX CMP).
You’ll need to set MENU:MIC BIAS to ON, and I also recommend setting MIC BTN to OFF.
You can tap the XMIT button to start voice-mode transmit, or use VOX. See VOX menu entries in the owner’s manual.
Note: There’s a rumor that one legacy version of the iPhone headset was different from the others. I don’t have any info on this, but it means there’s a slight risk that this $6 adapter won’t work in your case. But it certainly works with the earpods I bought a couple of months ago.
Thanks for sharing this, Mike! I’ve just placed an order for this little adapter. When doing field operations, I always use in-ear headphones, but a separate hand mic because I don’t like packing or wearing bulky headsets. I’ve a couple of earbud/mic sets (neither an Apple brand) that should work brilliantly with this adapter.
[Update: One of our readers purchased the K2/100! Thanks!]
I freely admit it: a lot of radios enter and exit my radio shack––especially portable receivers and SDRs of all stripes. It’s just the nature of doing gear reviews and evaluations. I also keep a fairly robust arsenal of radios here at SWLing Post HQ for future comparison reviews and evaluations as models are upgraded.
But amateur radio transceivers that I personally use at home and in the field––? These come and go much less often.
I feel lucky in that I get exposure to most of the radios currently on the market. Yet I’m also cursed in that I simply can’t turn off that internal reviewer when I use a radio! I’ve become a bit extra-critical, hopefully constructively so, of radio ergonomics, user interfaces, functions, and of course, performance.
I used to have a healthy selection of transceivers in my shack as well, but over the years I’ve found it necessary to distill them down to just a few––almost all of which, if you’re curious, are Elecraft models.
My Elecraft KX1 in the Pelican 1060 case which fit it and its accessories perfectly.
One of the first Elecraft rigs I owned was the KX1, the ultimate handheld field portable 4-band CW radio of its time. I believe I acquired it in 2008. SWLs will be interested to know that I could even tune to broadcasters on the KX1, using ECSS.
The Elecraft K1 (Source: Elecraft)
I loved the KX1 so much, in fact, shortly thereafter I purchased a K1. The latter I ended up keeping for perhaps one year or so.
Soon thereafter, I purchased an Elecraft K2/10 (the “/10” stands for 10 watts).
I should note here, for those who are not familiar, that almost all of Elecraft’s products are available in kit form. The K1, KX1 and K2 are proper kits. You can’t buy them factory built at Elecraft. With that said, I’ve never had the pleasure of building any of these models from kit form because I purchased them second hand.
The Elecraft K2
The K2 has been in production now for twenty years (!!!) and it still has a healthy market and dedicated community. The K2 must be one of the best documented, benchmark performance through-hole kit transceivers ever made. Because of the robust user base and the fact Elecraft still produces it, it’s also one of the easiest radios on the market to diagnose and repair. The thing was designed to be a “hands-on” radio–to be pulled apart and serviced–there’s no mystery meat inside.
I used my K2/10 for many years…and assured myself I’d never sell it.
Ah, the best laid plans of mice and men…! In 2011 Elecraft introduced the venerable KX3 and I fell head over heels for that radio (just read my review). All of a sudden, my trusted K2/10 wasn’t getting as much air time and started collecting dust, so I (reluctantly) sold it to free up some radio funds.
Then, within weeks of selling my K2/10, someone posted a K2/100–a 100 watt version of the K2–for sale on our local radio club’s email group. No one in the group showed interest. The sale was for a late local ham, now SK (silent key), and his friend who was selling off the equipment really wanted to unload it quickly for the benefit of his family. I expressed interest, and only two weeks after selling my K2/10, I was a K2/100 owner.
I figured this must be the universe intervening because, had I not sold the K2/10, there’s no way I would have had funds to purchase the K2/100.
After purchasing the K2/100, I sold my only other 100W rig: my beloved Ten-Tec OMNI VI+. I had been the owner of the OMNI VI+ for more than a decade and it was a radio I dreamed about in the 1990s. Still, it took up way too much table space in my modest little shack and, yet again, I needed to consolidate.
Activating PK01 (The Appalachian Trail) with the KX2 during the amazing National Parks On The Air event.
Fast forward a few years to the day before the 2016 Hamvention: Elecraft announced their new field portable radio, the Elecraft KX2. The Elecraft team gave me early access to the KX2 and once again, I was head over heels for this new rig. When I started my review of the KX2, I already knew I wanted one, so didn’t even bother reaching out to Elecraft for a loaner––I just bit the bullet and purchased it. Click here to read that review. Shortly after making this purchase, I sold my KX1.
If you’ve been keeping track thus far, you’ll note that I currently have: an Elecraft KX3, an Elecraft KX2 and an Elecraft K2/100.
You’d think I was an Elecraft fan, but that’s not entirely the case. Elecraft KX series transceivers simply suit my operating style and meet my performance expectations. Why?
Recently, I’ve come to realize that although I still love the K2/100 in so many respects, I reach for my KX3 and KX2 more often…even though the K2 is my only 100-watt transceiver.
For this reason, I’ve decided I must sell the K2/100 so that I can fund the purchase of the (rather pricey) Elecraft KXPA100 amplifier. With the KXPA100, both my KX3 and KX2 will have a 100-watt linear amplifier at their disposal. Integration is seamless, and the amplifier is quite portable. With the KXPA100, I’ll be able to run a “full gallon” on Field Day on two radios I know like I know the back of my hand (especially the KX2!).
It has the latest firmware and includes all modifications. It’s fully-loaded, too–here are the options:
KPA100 K2/100 Internal Integration Kit
K160RX 160M and 2nd RX port
KDSP2 SSB Adapter (which is now discontinued)
KNB2 High Performance Noise Blanker
KSB2 SSB option
The only option it lacks, as far as I can tell, is the K60XV (60M and transverter adapter).
I’m hoping to sell the K2/100 for about $900 shipped (unless you, gentle readers, advise otherwise).
My K2/100 will be on view at the Winston Salem, NC hamfest this weekend, where I plan to hold down a table with my buddy, Vlado (NC3Z). I doubt I’ll sell it there, so will likely post it online later.
Here’s the thing, though…I look at this awesome little radio and wonder why I’m selling it! And then I close my eyes….take some deep breaths…and remember that it’s all about consolidating the shack and maximizing the potential of the KX3 and KX2.
And, who knows? Maybe the universe will intervene once again, and I’ll own another K2 in the future.
Post Readers, weigh in: What radios have you bought and sold? Any regrets? Which have been, or are still, your favorites––and why?
The Yaesu FT-890: One of many general coverage HF transceivers spotted in the 2017 Hamvention flea market.
Many thanks to SWLing Post reader, Joe, who writes:
I’ve been practicing for my Technician ham radio license here in the US and am ready for the test. I’m already looking at HF transceivers even though I don’t have my General license yet.
Here’s what’s important to me:
I will still do a lot of SW DX
Something that has at least decent audio
Something that isn’t too too huge; though I’m a little flexible on size
I need something that has a receiver that handles weak DX well
I’d be comfortable spending $500 any day all day no problem. Anything higher than that and I’d really have to think it’s an investment in my radio future.
Thanks for your question, Joe, and allowing me to post it here for comment as this is one I’m frequently asked.
First of all, congratulations on studying for and taking your ham radio license exam! I’m a ham and absolutely love the radio privileges my license provides.
At the same time, I’m still more of an SWL than a ham–meaning, I spend way more time chasing SWL DX than doing on-air ham operations.
With that said, I always seek radios that will serve me well as both a ham and SWL, if possible.
My humble advice
If we stick with your $500 budget strictly, then we’re certainly looking at used transceivers. That’s okay–there are many good ones on the market!
I posted the following review of general coverage transceivers a few years ago. The info in it is still very much accurate in the used market. I would suggest you give it a good review as it goes into more detail about the ins and outs of your first transceiver and the importance of leaving budget to purchase a good power supply:
Comparing the size of the Elecraft KX3 (top) and KX2 (bottom) at Elecraft’s Dayton Hamvention booth.
You can find the KX3 used for $700-900 (depending on options). The bare-bones model of the KX2 can be purchased new from Elecraft for $749.
Of course, something to keep in mind about the Elecraft KX series transceiver is that output power is limited to 12-15 watts. Some of the general coverage transceivers mentioned in our review have a much higher 100 watt output power.
Additionally, the audio fidelity (via the internal speaker) is not as good as many other general coverage transceivers. Audio amplification is not as powerful, because both transceivers are designed to operate on a small battery pack (a major plus in my world because I love field-portable rigs).
Since I do 90% of my radio work with headphones, audio amplification is not a problem for me and I’m quite please with both KX line transceivers. Many KX series owners purchase external amplified speakers to improve audio.
New, the IC-7200 is about $879 US, but they can be found used closer to the $650 – 750 mark. A very good value in my book. In fact, I’m very tempted to buy one as my 100 watt “shack and field” rig. It’s way more user-friendly on Field Day than my Elecraft K2/100 and, in many ways, a better option than purchasing an Elecraft amp for my KX3/KX2.
Any other good suggestions?
The Kenwood TS-480SAT is full-featured, small, and has a detachable face plate. A very good general coverage transceiver.