Tag Archives: SDR

Video: Uncovering a Buried Co-Channel Station with the New AirSpy SDR# Tool

AirSpy’s Youssef Touil shares a video from YouTube author “PY3CRX&PY2PLL” which dramatically demonstrates the extent to which the Co-Channel Canceller tool can uncover a much weaker signal beneath a powerful one:

Youssef commented on the video that It only needs some tweaking to the lock/offset to get a perfect decode. So, presumably the result could be even better than heard here.

For more information on the Co-Channel Canceller, see my original article here, and the follow-up piece.

Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington.  He’s a regular contributor to the SWLing Post.

Spread the radio love

SDR#’s Co-Channel Canceller Gets Additional Options

In my earlier article, I introduced the Co-Channel Canceller, a unique feature in AirSpy’s SDR# program for the benefit of medium wave DXers.

Now only a day later, software author and AirSpy founder Youssef Touil expands the toolset of Co-Channel Canceller with I.F. Offset and Channel Bandwidth controls.

To download this latest release, click here to go to AirSpy’s downloads page.

It’s my hope that AirSpy will publish a tutorial or YouTube video(s) with step-by-step examples to help with using this unique feature. Until then, it’s certainly fun to try!

Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington.  He’s a regular contributor to the SWLing Post.

Spread the radio love

AirSpy SDR#’s New Killer Feature: the Co-Channel Canceller

An example of an AirSpy SDR# software screen.

A version of AirSpy’s popular SDR# software, showing the dark mode interface introduced in 2019. SDR# is always evolving, and the latest new tool is the Co-Channel Canceller.

It’s easy to take for granted the magical math that happens in Software Defined Radio. Occasionally though a breakthrough occurs which really grabs our attention, thanks to the hard work and bright minds of the designers behind the receivers and the software.

On the software side, the first series of “wow” moments happened for me in 2007-2008 when Nico Palermo of Perseus SDR fame expanded the program’s alias-free bandwidth incrementally from a modest (but impressive for the time) 100 kHz all the way up to the current 1600 kHz coverage.

The top-end 1600 kHz bandwidth was a game changer which allowed  medium wave DXers the opportunity to record IQ-WAV files of the entire band for later review, analysis, and DXing. It’s even more impressive considering this expansion was done without any additional hardware or receiver updates.

What did Nico charge Perseus owners for this incredibly useful expansion of spectrum and waterfall bandwidth? Nothing! The program with its much improved features continued freely available to previous and new Perseus SDR owners.


Now in 2020, Youssef Touil, AirSpy’s hardware and software developer, brings  a “killer feature” to his own SDR program named SDR#, for the benefit of medium wave DXers: the Co-Channel Canceller. The cost for this innovative tool? Yep, it’s a free addition to SDR#.

What are the benefits of the Co-Channel Canceller? This question is best answered by listening to three examples published by Youssef on his Twitter feed.

Read the descriptions below and listen to the brief audio files. In each example the Co-Channel Canceller is turned on and off a few times:


For the first example above, I suspect the 594 kHz station is Saudi Arabia’s Radio Riyadh, and the off-channel 596 kHz signal is Al Idaa Al-Watania from Morocco. It’s impressive that the 50 kw 596 station can be uncovered to any degree, as Radio Riyadh is a whopping 2000 kw!

In the AirSpy Groups.io forum, Youssef clearly illustrates the steps needed to initiate the Co-Channel Canceller. I’ve reproduced his screenshots below:

I’ve only just begun to explore the possibilities of the Co-Channel Canceller tool, but it holds promise of helping to reveal and identify hopelessly buried co-channel or adjacent channel stations. Not only does it work “live” in real time reception, it functions well with recorded IQ-WAV files too! Checkout the newest version of SDR# and give this new feature a try. I can imagine situations where this tool could be highly useful at times for the shortwave DXer also.

Thanks, Youssef, for this brilliant tool, which you’ve included free with the newest SDR# !

I encourage radio hobbyists to support AirSpy’s efforts to advance the state-of-the-art. The diminutive AirSpy HF+ Discovery receiver is not only a reasonably priced SDR to use with SDR#, it’s a top performer and a recipient of the World Radio TV Handbook’s Best Value SDR award for 2020.

Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington.  He’s a regular contributor to the SWLing Post.

Spread the radio love

Radio Waves: The “Weird Wide Web” of SW, VOA Whistleblower Complaint, KiwiSDR v RaspberrySDR, and the Portable Operations Challenge this weekend

Radio Waves:  Stories Making Waves in the World of Radio

Because I keep my ear to the waves, as well as receive many tips from others who do the same, I find myself privy to radio-related stories that might interest SWLing Post readers.  To that end: Welcome to the SWLing Post’s Radio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!

Many thanks to SWLing Post contributors Steve Lord, Michael Guerin, and the Southgate ARC for the following tips:


Propaganda, Pirates and Preachers: The Weird Wide Web Of Shortwave Radio (The Dork Web)

The world of Shortwave is a world of state-backed propaganda, cults, pirates, and spies. You’ll find every form of freakery and geekery on air. Digital, analogue, even stuff where you can’t tell if it’s digital, analogue, bad music or interference.

[…]In a world of constant connections Shortwave radio may seem anachronistic. But there’s something special in Shortwave and I’d like to show it to you. With a tiny bit of effort and at zero cost you can explore this world from the comfort of your own home.

How Shortwave Shaped Lives

Of all the things I expected to get into, Shortwave radio wasn’t one of them. As a kid I’d listen to my dad’s old valve radio. Strange voices from distant lands floated through the air. Shortwave’s audio quality was terrible even by early 80s standards. There was something magical in hearing distant voices from across Europe and beyond.

I got back into Shortwave listening earlier in the UK lockdown period. Over the past few months I’ve heard stations from as far as Florida, Cuba, Botswana, North Korea and China. I’ve heard signals broadcast from Ascension island in the Atlantic to Tinian island in the Pacific.

Some people will tell you that Shortwave is dead. While it’s passed a 20th century peak there’s plenty happening. In 2002 the National Association of Shortwave Broadcasters estimated that hundreds of millions of households around the world had Shortwave-capable receivers.[]

Six senior Trump admin officials file whistleblower complaint over Voice of America CEO (The Hill)

Six senior Trump administration officials filed a whistleblower complaint with the State Department’s inspector general over allegations that Michael Pack, CEO of the U.S. Agency for Global Media (USAGM), violated federal law and abused his authority, according to a copy of the complaint reported by Politico on Wednesday.

The 32-page complaint includes allegations from six members of the Senior Executive Services at the USAGM accusing Pack, who was confirmed as head of the agency which oversees the state-run network Voice of America in June, of engaging in conduct that “constitutes an abuse of authority and gross mismanagement.”

The six officials who filed the complaint were all placed on administrative leave Aug. 12.

The complaint alleges Pack, who was appointed by Trump, wanted to force out the complainants because they were part of the “Deep State” and had “played a role in the delay” of Pack’s confirmation to his position at the USAGM.

The complaint alleges Pack ordered a close aide to conduct research on the voting history of agency employees, including one of the complainants, Matthew Walsh, the deputy director for operations who was placed on administrative leave. The research “was to be utilized in evaluation of career civil servants’ abilities to carry out the duties of their positions,” the complaint states.[]

KiwiSDR vs RaspberrySDR— a tale of two SDRs (Hackaday via Southgate ARC)

Once you move away from the usual software defined radio (SDR) dongles, you have only a few choices unless you want to drop some serious cash. One common hobby-grade SDR is the KiwiSDR. This popular unit runs Linux and can receive up to 30 MHz. The platform uses a dedicated A/D converter, an FPGA, and BeagleBone computer. Success of course breeds imitators, and especially when you have an open source design like the Kiwi, you are going to find similar devices with possibly different end goals. That’s how the RaspberrySDR came to be. This is a very similar unit to the KiwiSDR but it uses a Raspberry Pi, along with a handful of other differences. What’s different? [KA7OEI] tells us in a recent blog post.

Other than the obvious difference of the computer and all that it entails, the RaspberrySDR has a higher speed A/D (125 MHz vs 66 MHz) and 16-bits of resolution instead of the Kiwi’s 14 bits. This combines to give the Raspberry a wider receive range (up to 60 MHz) and — in theory — better performance in terms of dynamic range and distortion.

[KA7OEI] measures a few key parameters on both devices and arrived at some surprising conclusions. The Kiwi appears to boost signals near its cutoff frequency to compensate for losses in the system. The Raspberry — using adapted software — looks as though it does the same trick, but does it around the Kiwi’s cutoff frequency, which is lower. Probably a software fix could take care of that, of course.

There are also tests of image rejection and front-end overloading. The tests revealed a few problems with signal strength measurement and some other problems with the RaspberrySDR. The biggest issue, though, was that the 16-bit A/D didn’t seem to have better performance. Without proper design, throwing more bits at a problem isn’t always helpful and this appears to be a good example of that.

In the end, the Raspberry looks like a cheap clone of the Kiwi with some benefits, but also some drawbacks. The blog post also covers some open source issues where Kiwi is now saying some parts of their code will only be binary in the future and there has been some difficulty finding all of the Raspberry’s files. If you are looking to buy one, you might not find the name “raspberrysdr” but [KA7OEI] suggests searching for “New 16bit 62M real-time bandwidth network shared SDR receiver” which does turn up some results.

Of course, you can always use a Pi with a more conventional dongle, and that works well enough. If you want to make a Pi just transmit, you can do that with little more than a wire, although the quality might not be perfect.

https://hackaday.com/2020/09/30/kiwisdr-vs-raspberrysdr-a-tale-of-two-sdrs/

Portable Operations Challenge (Southgate ARC)

The final rules for the FMH Portable Operations Challenge are now posted on the POC webpage at foxmikehotel.com/challenge/. N1MM+ users, need to select FMHPOC as the contest and VKContest Logger users just POC.

The organisers wish all other contests taking place this weekend success and lots of fun – the bands will be busy again and we’re hoping propagation plays along.

We hope many amateurs give this new-style contest a go whether from a home QTH station or out portable.

Ed DD5LP


Do you enjoy the SWLing Post?

Please consider supporting us via Patreon or our Coffee Fund!

Your support makes articles like this one possible. Thank you!

Spread the radio love

SDR# upgrades include device sharing and spectrum slicing

Youssef with Airspy has just announced the release of the latest SDR# version. He wrote the following in a tweet:

Check the latest and greatest release of SDR# with device sharing across multiple instances covering different slices of the spectrum.

[…]One master instance can spawn many slices with entirely separate signal paths and displays.

Click here to download SDR#.

Spread the radio love

The RX888 SDR – Up Close Photos

I received my new RX888 SDR receiver today, via DHL shipping in only seven days from ordering on Ebay from seller “shenglongsi”. I’ve noticed that some Chinese Ebay sellers use a placeholder shipping number when choosing the DHL carrier, and then some days later they forward the actual shipping number when the product is out the door.  That was the case with the RX888– four days in limbo, and then BINGO!–a real tracking number was sent and the package arrived three days later.

It should be noted right up front, as others have pointed out, the RX666 and RX888 SDRs are commercial implementations of the excellent, open source BBRF103 receiver. The BBRF103 is the creation of talented Italian designer Oscar Steila IK1XPV.

Hopefully tonight I’ll be sorting out files to get the radio operating, and if there are hiccups along the way I have help from some other early adopters around the globe.

The radio arrived with zero documentation or links to support files, but I already have files known to work with the RX666. The receiver should work with HDSDR after the correct additional files are added to the HDSDR folder, as does the similar RX666 model. Cypress USB drivers also need installation on the host computer. One concern is operating the LNA (low noise amplifier) on the RX888, which the RX666 lacks. This may take a different EXTIO .dll file than the one intended for the earlier RX666.

I’m aware of the developer of another popular SDR program who will almost certainly add support for the RX888/RX666 to his software.

I’ve read that the powerful ADC chip inside these two models is a USD ~$60-70 component (or from the same chip series) which is also found in a few commercial grade SDRs plus the newer WinRadio G33DDC & G35DDCi models. Translation? The RX666 & RX888  could turn out to be amazing performers for the price.

Below are up-close pictures of the receiver’s printed circuit board. Construction and soldering look quite good considering the USD $188 price. In my opinion the build quality appears to somewhat exceed that of the RX666, which was the first of these two units on the market.

Note that in the last photo the whitish square on the bottom of the PCB is a thick foam pad, perhaps some thermal transfer material. It is sticky-backed and placed so that it’s wedged between the bottom of the chip (ADC?) with the blue heat sink and the bottom of the case.

In the below photo, note the small LEDs with indications “PWR”, “MODE”, “OVLF”, and “MODE” (again). At the upper-right corner are two pads marked “RST” (reset?).

Guy Atkins is a Sr. Graphic Designer for T-Mobile and lives near Seattle, Washington.  He’s a regular contributor to the SWLing Post.

Spread the radio love

The New RX-888 16 bit ADC Direct Sampling SDR with 32 MHz bandwidth

Many thanks to SWLing Post contributor, H. Garcia (PU3HAG), who writes:

While doing the daily eBay and AliExpress strolling for new and cool radio stuff, this showed up:

RX888 ADC SDR Receiver radio1.8GHz 16bit direct sampling HF UHF VHF HDSDR

Like the DragonFly RX-666 you posted about recently, it’s based on IK1XPV Oscar’s BBRF103 works. Both share a hefty metal case.

I really like this seller of RX888 on eBay. The person provided quite a bit of technical details. The seller is also up-front about the current challenges regarding thermal issues, software stability and bandwidth available above 32MHz.

(How many manufacturers let you know in advance the negatives? I like this guy!).

The bandwidth limit above 32MHz is a curious one. Apparently, coverage above VHF and UHF coverage relies on Rafael Micro’s R820T2 tuner chip (also used on RTL dongles and AirSpy R2 and AirSpy Mini). However, R820T2 can only push a slice of 8 to 10MHz of the spectrum into RX888’s ADC. So, FM broadcast DXers, be warned. You may need to use a downconverter that brings the 88-108MHz to 8-28MHz. Perseus SDR uses this approach.

Another interesting tidbit. As we know, TaoBao is a huge marketplace, but their sellers focus exclusively on the China market (very few also deliver to South East Asia). There are LOTS of cool, never-seen-before products on TaoBao that don’t have visibility to us here in the Western hemisphere. The RX888 was one of them, I recalled seeing it about a month ago and thinking “Hey, this is so cool, why are they not selling it on AliExpress yet?”

Thank you so much for the tip! I agree with you: it’s refreshing to read not only a thorough eBay description but also frank comments from the seller.

I must admit, the receiver world is going through a dynamic change and its champion is the SDR. It’s hard to keep up with the innovations and technology is pushing limits I could not have imagined even a decade ago.

I’m looking forward to checking out these super wideband SDRs like the RX-666, RX-888, and the ELAD FDM-S3.

Click here to check out the RX-888 on eBay (partner link supports the SWLing Post)


Do you enjoy the SWLing Post?

Please consider supporting us via Patreon or our Coffee Fund!

Your support makes articles like this one possible. Thank you!

Spread the radio love