Author Archives: Guy Atkins

BELKA-DX: A Pocket-Sized Radio for Pocket Change

Well, not pocket change for most people, but I couldn’t pass up a clever headline!

I want to alert SWLing Post readers to a lower cost option for the new BELKA-DX than the Mobimax source: the ecommerce web site of Alex Buevky (EU1ME) who designed the radio.

In early February I bought the original BELKA DSP from the designer’s site, for a total of $117 USD. It arrived safely in 10 days to my Washington State address, with free tracked shipping included.

Yesterday I ordered the new BELKA-DX from the same web site, and the grand total was 340 BYN, or in US Dollars, $128, tracked shipping included.

If I had ordered from Mobimax, the total would have been 176.91 Euro, or $205.76 USD. That price includes FedEx shipping, the only available option to the USA.

Purchasing from the BELKA-DX designer’s web site in Belarus saved me nearly $78, and I’m confident I’ll receive this new model in about a week and a half as before (hopefully no COVID-19 related delays).

I had no issues this time or previously with my payment being “flagged” for security concerns. I used my PayPal VISA card and the transaction completed without issues.

For more information on this tiny powerhouse receiver, see Georges Ringotte’s (F6DFZ) brief review here on the SWLing Post.

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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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.

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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.

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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.

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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.

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A Compact RSPdx & Wellbrook Loop Kit for the Beach — My Approach

I have enjoyed three to four medium wave and shortwave DXpeditions per year since 1988, to sites on the Washington and Oregon coasts. I love the chance they give to experiment with antennas in a (hopefully!) noise-free location, and concentrate on catching stations that might not be heard from home.

All of my DX trips have been via car–until now! I’ve just returned from nine vacation days in Hawaii (Waikoloa Beach, on the Big Island), and I thought others might like to see the radio related items I chose to take along for air travel. I’m pleased to report that everything worked as planned, and I have five days of SDR IQ WAV files of the MW band for review, all recorded in the time frame surrounding local dawn.

My goal was not the smallest, most compact portable setup, but one with high performance and modest size. Fitting everything into a day pack was another requirement. A simple wire antenna and an even smaller Windows tablet or laptop than the one I’ve used (and a smaller SDR like the HF+ Discovery, for that matter) would make a much smaller package. However, the items I’ve assembled worked excellently for me during my enjoyable Hawaii vacation. The directional loop antenna provided nulls on medium wave of 30 dB during preliminary tests indoors, a less-than-ideal test situation.

Waikoloa Beach–just one of a zillion picturesque scenes in Hawaii.

Here is a list of what I’ve put together for my DXing “kit”:

    • SDRPlay RSPdx receiver
    • Short USB cable for receiver<>PC connection, with two RFI chokes installed
    • Lenovo X1 tablet— a Windows 10 device with magnetically attached keyboard; this model is a competitor to Microsoft’s Surface Pro tablet
    • Wellbrook Communications’ ALA1530 head amp module, modified for female SO239 connectors enabling use of large diameter LMR-600 coaxial cable as a 2-turn loop element. My antenna setup is similar to Wellbrook’s commercial flexible loop
    • Wooden base for the antenna (ALA1530 is bolted to the base)
    • 20 feet of lightweight RG-174 coax
    • Wellbrook DC interface module for the ALA1530
    • 3.0 Ah LiFePO4 rechargeable battery for the Wellbrook antenna
    • 15 foot long section of high grade “Times Mfg.” LMR-600 coax cable with PL259 connectors (bought from Ebay already assembled/soldered)
    • Fold-up beach mat
    • Small day pack to hold everything

All the contents of this DXing setup fit a standard size day pack.

You’ll note the absence of headphones in the list. This is because my intent from the start was to record all the DX (MW band) as SDR WAV files for DXing post-vacation. That said, I did have headphones in my travel luggage for later spot checks of a few frequencies. That’s how I found 576 kHz Yangon, Myanmar lurking at their 1700 sign-off with national anthem and English announcement. The remainder of the DX to be uncovered will have to wait until I’m back home near Seattle!

The LMR-600 is a very thick and stiff coax cable, whose diameter approaches that used in the standard aluminum tubing ALA1530 series from Wellbrook. It has the benefit of being self-supporting in a 2-turn configuration and will also coil up into an approx. 12-inch package for transport. It just barely fits within the day pack I’m using. As I understand it, magnetic loops with tubing or large coax as the active element, versus simple wire, are more efficient in operation. Whether or not this holds true in practice remains to be seen.

I fashioned a wooden disc 3/4″ thick to attach the ALA1530 head amplifier, as I didn’t want to bring along a tripod or other support stand. The Wellbrook antennas all work well near or at ground level, so I was able to get great reception with the antenna right on the beach. The diameter at two turns of the coax is only a few inches smaller diameter than Wellbrook’s aluminum tubing loops. Three strips of strategically placed Velcro straps help keep the turns together when deployed as well as during storage.

In theory a two-turn loop should give 5 dB less gain than a single turn version; however, my older ALA1530 module has 5 dB more gain than the newer “LN” type, according to Andrew Ikin of Wellbrook Communications. The net result is that my two-turn antenna should have equal gain to the larger one-turn variety. Future experimentation with this DIY coax loop antenna is in order!

The Wellbrook loop antenna, RSPdx receiver, and Windows 10 tablet on the beach in Waikoloa, Hawaii.

Another view of the DXing position. Being this close to the water with my radio gear was unnerving at first, but the wave action on a calm Hawaii beach is totally different from the Oregon/Washington beaches with waves that can move in and out by a hundred feet or more.

The Wellbrook “DIY FlexLoop” works fine at beach level, and is less conspicuous this way, too.

The ALA1530 module is bolted to the 11-inch wooden disc for support. I’ve modified the module’s sockets to securely hold SO239 female connectors.

The commercial Wellbrook FLX1530LN is a fine product, and worthy of your consideration as a compact and high performance travel antenna. Full details can be found at this link.

SDR WAV Files for Download

One of my goals from the start for my Hawaii trip was to bring back SDR “IQ” WAV files for sharing with others. These approx. 900 Mb files cover the entire medium wave band as heard from my beach location in Waikoloa.

The overall page is: https://archive.org/details/@4nradio   Clicking on any of the entries will bring you to a details page. From there just right click on the “WAVE” link, and choose “Save as…” to download. For a few of the recordings I also posted the file that precedes the one that goes across the top-of-the-hour, because things seemed a bit more lively prior to 1700 (which  was at local sunrise, give or take a couple of minutes).

The IQ WAV files are only playable with suitable SDR radio software: SDRuno is first choice (but you need a RSP receiver connected). The files are also is compatible with HDSDR and SDR-Console V3. It may also play on Studio 1 software.

I hope other DXers enjoy the chance to tune through the MW band, as heard from the Big Island of Hawaii.

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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Amazon Price Drop: Eton Elite Executive Portable Now $129.99

The relatively new Eton Elite Executive, formerly Eton Executive Satellit, has dropped $50 USD on its Amazon page to $129.99:

This rather major price drop lowers the cost to just $20 more than Amazon’s price for the older, silver-cased Eton Executive Satellit. According to Jay Allen’s review the new radio has identical performance to the older model; only the color is updated.

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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