Monthly Archives: February 2020

KiwiSDR: A brilliant new map portal!

Last month, we noted that the popular SDR.hu KiwiSDR portal now requires registration and an amateur radio callsign to use the site. While SDR.hu is still online, we certainly get the impression all site development has been halted. This is not the end of the world because SDR.hu is only one of several KiwiSDR portals–we linked to others in our January article.

Personally, I only used the SDR.hu map view to keep track of KiwiSDR sites and found it quite useful because I typically select sites based on geographic location.

A better KiwiSDR map portal

I’ve just learned via the KiwiSDR Twitter account that Priyom.org has updated their KiwiSDR map portal using Dyatlov maps. The results are brilliant and, in my opinion, even better than the SDR.hu’s map.

The Priyom.org map uses the full window, is uncluttered and easier to navigate.

If you click on a KiwiSDR site, you’ll see a pop-up window with basic site information. If you hover the cursor over that site info, another window will pop up with current details about the receiver, number of users, antenna, SNR, and GPS clock (see above).

This is now my favorite way to geographically surf KiwiSDR sites.

Click here to check out the new map portal.

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Dan notes two eBay finds: one good buy and one too high!

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Many thanks to SWLing Post contributor, Dan Robinson, who recently discovered two note-worthy items on eBay.

The first is a WinRadio Excelsior SDR.

Dan notes:

A seller on eBay is offering the WR-G39DDCi. Just picked one up on a Buy It Now for $200.

He still has some up without Buy It Now but the price is creeping up. Heck of a deal considering the price new….

Click here to view this listing on eBay.

That’s simply amazing you found an Excelsior for $200! WOW! Perhaps this eBay seller will post more WR-G39DDCi units with a BuyItNow price? I’d be willing to bet these may have all come from a commercial or government auction.

The second item Dan shares is a Sony CRF-230 with original box.

Dan notes:

This guy is trying to get too high a price, but these 230s are rarely seen with the original box. There are many 230s on eBay and prices are usually in the several 100s of dollar range. Anyone considering this one should insist on seeing a video of the receiver powered on and working. The seller’s starting price level is at lest 2 to 3 times what a SONY CRF-330K would be in LNIB condition.

Click here to view on eBay.

A rare bird indeed, but as you point out, Dan, the BuyItNow price is astronomically high.

Note the seller does have a Make An Offer option, too. I suspect that’s what they’ll end up accepting if they ever wish to sell this unit.

Thanks again for sharing your eBay finds, Dan!

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Video: The Bell Telephone 1940s era mobile network

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

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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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FTIOM & UBMP, Feb 23-29

Radio Waves: Radio Bulgaria, Asur Community Radio, Digital Sign Compliance, and a Sound Card Scope

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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’sRadio Waves, a collection of links to interesting stories making waves in the world of radio. Enjoy!

Many thanks to SWLing Post contributors Marty, David Iurescia (LW4DAF), and Phillip Novak for the following tips:

Radio Bulgaria to resume its audio broadcast (Bulgarian National Radio)

“Radio Bulgaria needs to resume its sound presence and we are to work together with the team, in order to build a firm concept in this direction.” This was what BNR Director General Andon Baltakov said in his first interview with Radio Bulgaria.

On the eve of Radio Bulgaria’s 84th anniversary, which is celebrated on February 16, 2020, Mr. Baltakov said that broadcasts of the National Radio aimed for foreign countries would be modernized, but would preserve their philosophy – being Bulgaria’s window to the world and vice versa. You can read the whole interview here. […]

Radio aids revival of dying tribal language (The Hindu)

Tucked away in the hills of Jharkhand’s Latehar district, Asur, a particularly vulnerable tribal group, may not have access to good road or means of transportation to the outside world, but that has not deterred them from saving their language. Using mobile radio, the Asur community has been spreading the popularity of the language within their geographical limits.

As the voice Dahan-Dahan Turrarr .. Dang T inatang Turrarr.. Noa Hake Asur Akhada Radio Enegabu Degeabu Siringabu Urrarr (Come, sing, dance and talk.. This is Asur Centre Radio) is played out through loud speakers, the bustle at the weekly market at Kotia seizes briefly, as people turn their attention to the sound system that transmits songs and news transmitted in their native language.

Attention of the Asur tribals assembled at the market is immediately diverted to the sound system that transmits songs, news and information about government schemes — all in their native dialect.

[…]“The initiative has got a huge response from people. Now, villagers are requesting us to organise events at their places and they are also interested in preparing radio programmes,” said Ms. Tete.

“When we started working on languages, we focused on five tribal and four regional languages. Then we realised that the bigger groups can take care of their own languages, but smaller communities need help,” said Ms .Tete.

[…]Youth from the community are also being encouraged to write poems in their language and older ones narrate their experience in their own language.[…]

FCC Digital Sign Compliance (International Sign Association)

The U.S. Federal Communications Commission (FCC) continues to cite businesses because digital signs are interfering with the wireless spectrum, creating problems with commercial and public wireless devices. This may occur because the signs are operating at Electro Magnetic Interference (EMI) levels not allowed under U.S. federal law and in violation of FCC regulations.

Click here for frequently asked questions to better understand these issues.[…]

How To: Surface Mount Soldering (Nuts & Volts)

Some people tend to shy away from using surface-mount components in their projects. It seems to be too difficult or needs an array of specialized equipment. In the past, I found myself in this same mindset — wary of using these types of parts. That all changed when I got involved with an open source motor controller project (OSMC).

It used a mix of surface-mount and through-hole components. I took the plunge and built up a pair of OSMC H-bridge boards and the MOB (Modular OSMC Brain) controller board which I used in the Battlebot Crash Test Junior.

At the time, there was little information available on how to mount these parts using an ordinary soldering station and tools that most hobbyists would have on hand. Not wanting to invest in a whole new set of tools (hot air stations, etc.), I experimented a bit and used common sense techniques to get the job done. A point I’d like to stress is the myth about requiring anything exotic to work with most surface-mount parts. I don’t own or use any special soldering equipment for this. All of the soldering that I’ve done on surface-mount boards is built with an old Weller WTCPT station and TC201 soldering iron. It has the fine tip that came standard on it. If you happen to have access to specialized tools, go ahead and use them but you still may find these tips helpful. It has been my experience that depending upon your techniques, you can get by just fine in most instances without specialized tools.[…]

Turn Your Computer’s Sound Card Into A Scope (Nuts & Volts)

I’ve been using an oscilloscope for almost 50 years. It’s my go-to measurement instrument in every electronics project I work on, helping me debug and fine-tune hardware and software projects.

In this article, I’ll show how you can get started with a simple-to-use scope you probably already have. Best of all, it’s free! When you graduate from this simple scope, you can purchase a more powerful scope using the exact same user interface.

Full disclosure: I love scopes so much, 10 years ago, I joined Teledyne LeCroy — the third largest scope manufacturer in the world behind Tektronix and Keysight. However, I use the Digilent Analog Discovery 2 Scope (described in this article) in all my hobby activities and in the workshops I teach at Tinkermill — our hackerspace in Longmont, CO.

I think the free scope control software, Waveforms, is the simplest to use, most feature-rich pro-level software of any of the available options. Using a sound card as the hardware interface with Waveforms puts a simple — yet powerful — scope in your hands for free.[…]

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Dan shares memories of work at KGEI

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Many thanks to SWLing Post contributor, Dan Van Hoy (K7DAN), who shares the following comment in reply to our recent KGEI post. Dan writes:

It was my privilege to work at KGEI as a broadcast engineer and antenna rigger with FEBC from 1981-85. After that we went off to serve FEBC in Davao City in the Philippines. Never had any problems with the 50KW GE transmitter except one night when a driver tube failed. Nice to have a transmitter you could walk into! It was back on the air in about 45 min with a new tube. Mario Barahona was the main announcer most nights faithfully bring the Good News from the Voice of Friendship in Spanish.

I also painted the building tan with a dark brown trim while I was there. As I recall, I painted the KGEI name in dark brown too. The biggest project for me was helping install the TCI 16 folded dipole slewable array with reflecting screen stretched between two 365 ft tall towers. I was the only antenna rigger on the project.

The 250KW transmitter was primarily used for Russian broadcasts over the North Pole using the TCI antenna. The ERP was somewhere between 15-20 million watts depending on how the antenna was slewed. We were often heard loud and clear in a variety of home devices in nearby Foster City. I called the 250KW transmitter the worlds biggest Heathkit. It was ably maintained by an amazing radio engineer named Loch Gordon. Jack Brooks, WA6DBT, was the station manager. Hiley Rainer was the jack of all trades do it all engineer. It was one of the most enjoyable periods of my life.

Wow, Dan…I had no idea! Thank you for sharing those wonderful memories. I can’t imagine singlehandedly installing the antennas you did! I need to call you next time I have an antenna hanging party!

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