Radio Prague: Underground agents and plots in the Cold War broadcasting war


Many thanks to several SWLing Post readers who shared the following story from Radio Prague:

Underground agents and plots in the Cold War broadcasting war

In this week’s Czech History we look at one aspect of the Cold War, the use of secret agents to spy on and disrupt the enemy’s propaganda services. In particular, we focus on the circus that surrounded the return of a Czechoslovak double agent Pavel Mina?ík 40 years ago in 1976 which was aimed at discrediting the US financed and Munich-based broadcaster Radio Free Europe.

Click here to read the full article and listen to the radio documentary on Radio Prague’s website.

Paul Litwinovich on “The Life, Decline and Possible Rebirth of AM”

Zenith-Shuttle-DialMany thanks to the SWLing Post reader who noted this latest post by Paul Litwinovich at WSHU (Paul is frequently referenced here on the Post).

A short excerpt:

“AM occurs elsewhere in nature. A lightning strike or manmade electrical discharge will produce a burst of electrical noise that varies in amplitude. Since AM radios are designed to detect variations in amplitude, this is why they are prone to interference from such things. AM held sway as the primary method of modulating a radio wave up to WWII, not only for broadcasting, but for all types of radio communications.

Every vintage consumer radio, be it standard broadcast or shortwave, up to WWII, received amplitude modulated signals. Nowadays, AM broadcast stations are associated with lower quality audio, but such was not always the case. Receiver design really came of age in the 1930s with the superheterodyne circuit and advancements in loudspeaker design. The grand floor consoles of the late 1930s leading up to WWII were capable of producing audio that was very good, even by today’s standards, the only exception being that they were monaural, as stereo technology was still a ways off.”[…]

Litwinovich’s article is a must-read as he gives a concise overview of amplitude modulation, AM vs. FM, and even covers current proposed uses of the broadcast band (something we’ve also recently mentioned).

Click here to read The Life, Decline and Possible Rebirth of AM.

Radio World: Schenectady Shortwave Transmitters, 1941

philco38-4_dial_1Many thanks to SWLing Post contributor, Dan Robinson, for sharing a link to the following article in Radio World:

The General Electric Co. was truly among America’s premier broadcasting companies.

In addition to developing much of early broadcast technology and building a trio of high-power AM stations in the early 1920s — WGY Schenectady, N.Y.; KOA Denver; and KGO Oakland, Calif. — GE was also the country’s pioneer shortwave broadcaster.

GE’s initial shortwave station, 2XI, first broadcast in 1923, and in 1924 it was used to relay WGY’s programs for to KOA and KGO for rebroadcast in the western U.S.

By 1925, there were two experimentally licensed shortwave stations in Schenectady: W2XAD and W2XAF. A third GE station in San Francisco, W6XBE, was added in 1939.

That was the year that the Federal Communications Commission allowed the country’s experimental shortwave stations to relicense as commercial operations, and these three GE stations received the call signs WGEA, WGEO and KGEI, respectively.

Continue reading the full article at Radio World.

Shortwave Numbers Stations on The Daily Beast


Interest in shortwave numbers stations seems to wax and wane. We’re currently going through a period of increased interest (again) as I’ve been receiving quite a few messages from new readers asking where to find spy numbers and what type of shortwave radio is needed. Truth is, there are fewer and fewer numbers stations still on the air, though some are still quite reliable (like HM01).

The following article by Shane Harris at The Daily Beast is one of the better, more detailed, articles I’ve read in the popular press.

(Source: The Daily Beast via Southgate ARC)

The Stupidly Simple Spy Messages No Computer Could Decode

by Shane Harris

When I was 10 years old, I found a shortwave radio in a crumbling old leather trunk where we kept family photos and other memorabilia.

As I spun the dial, tinny, modulating noises, like the song of an electronic slide whistle, emanated from the radio’s small speaker. Staticky cracks and pops competed for airtime. The sounds swished and swirled, unintelligible and unremarkable. But then, emerging through the clamor, was a voice.

I might have run right over it with the dial, but the voice’s rhythmic, steady pacing caught me up short. It wasn’t a deejay. Nor a commercial. And he wasn’t singing. He was just speaking. The same line, over and over again.

“7…6…7…4…3.” Pause. “7…6…7…4…3.”

I don’t remember if those were the exact numbers. But they were numbers. A repeated sequence which had no obvious meaning, and was entirely devoid of context. To find him here, amidst the screeches and howls of the shortwave frequencies, was like coming upon a man standing in the middle of a forest, talking out loud to no one.

How long had he been here? Who was he talking to? He had that officious tone of the recorded telephone operators who chastised you for dialing a wrong number. “Please hang up, check the number, and dial again.” And the same distracting static I’d heard in those messages filled the background. I wasn’t sure if he was speaking live, or if he’d been recorded and set loose to play into the air.

But there was an urgency to his tone. And a purpose. As if he were talking to me. Imploring. Listen. Hear me now. 7…6…7…4…3. Did you get that? 7…6…7…4…3.

I was simultaneously terrified and captivated.[…]

Continue reading at The Daily Beast…

The Heathkit GR-78: Ed’s “basket case” radio

BasketcaseMany thanks to SWLing Post reader, Edward Ganshirt, who writes:

I picked up this Heathkit GR-78 at a estate/moving sale. It was in a pile of “e-waste” (you know, old vcr’s broken TVs, remote controllers, dead cell phones, etc.).

I found a container and sorted through the stuff to retrieve all what looks like Heathkit parts. The radio was disassembled and scattered about. I was able to collect all the critical components and brought the works to the sales table. The person manning the table said that was stuff they were discarding and I could have it for free but the Easter basket was $0.50.

So far I had put little time into it but was able to mechanically assemble it completely. All the fasteners holding the cabinet were missing. The rest appears to be all there but the primary side of the transformer is open and the NiCads are shorted and stone dead. The manual that I found in their recycle bin is complete and appears to gone through 3 owners by 3 sets of handwriting in the notes and comments through out the manual. If anything this looks like a CSI/forensics troubleshooting process getting into the mind of 3 different owners unsuccessful at making it work.

I will keep you posted on the progress.


More power to you, Ed! There are few things as difficult as picking up where someone else left off on a kit build. Your project is exponentially more complicated since there were three people involved and parts are scattered.  Please update us with your progress.

Readers: If you have any experience with the GR-78, I’m sure Ed would welcome your input!

RIP: Dick Smith Electronics

dick-smithMany thanks to SWLing Post reader, Dan (VR2HF), who writes:

I must be a radio geek. While listening to Radio New Zealand (RNZ) top-of-the-hour news with my CC Skywave on the 31mb in a bus from Incheon Airport to my hotel south of downtown Seoul, I learned that Dick Smith Electronics ( will close all of its stores in Australia and New Zealand with the loss of about 3000 jobs. The complicated, sad saga of DSE which was sold by Dick many years ago, can be found here:

My first encounter with DSE was in the San Francisco Bay Area in the early eighties. I remember buying a few kits from them and Nolan Bushnell’s “Petster” robot cat. They also sold some Bearcat Scanners and Yaesu ham gear, as I recall. It is a far different business today than it was back then. If memory serves, I believe Dick Smith also had a store here in Hong Kong around 1980 when I made my first visit to the SAR.

I hope that someone in the Maker community with money and a vision will try a new, modern version of Radio Shack and the old version of Dick Smith Electronics. Offering a mix of 3D printers, Arduinos, Raspberry Pies, radios, and other items Makers might want could be a profitable business and fill a need.

Guest Post: Listening to 10 Meter Radio Beacons

SX-99-Dial-NarMany thanks to SWLing Post contributor, Mario Filippi (N2HUN) for the following guest post:

Listening in to 10 Meter Radio Beacons

Mario Filippi, N2HUN

(All photos courtesy of author–click to enlarge.)

Radio beacons can be found across the RF spectrum from the LF (low frequency) band all the way up to bands inhabited by satellite signals. If you are a ham, shortwave listener or a QRP (low power) buff then a great place to start is on the 10 meter band, which is included on most table-top shortwave radios and even some portables. Beacon signals come and go with band conditions, emanate from different parts of the globe and provide one with listening challenges and hours of fun. So let’s talk about 10m as it’s a good place to start.

A good indicator of band conditions on 10m is via the 10m beacon band which ranges from 28.1 to around 28.3 MHz. In general, most stateside beacons are found from 28.2 – 28.3 MHz while DX (ex-US) beacons are heard from 28.1 – 28.2 MHz. However, I’ve heard DX beacons as high up as 28.297 MHz. These stations provide hams and SWLs not only with code practice but with the adventure of hearing low power signals from around the globe. To get acquainted with what is on the air, check out the Ten-Ten International Net website which has one of best lists of beacons, along with a plethora of information on the band itself: . The Ten-Ten club has been around for many decades and is a good resource of information on 10 meters in general; one can even be issued a unique Ten-Ten ID number upon request. Then, when making 10m contacts you can exchange Ten-Ten numbers with fellow operators.


Let your fingers do the spinning of the VFO on 10m.

Many of these beacon stations have been logged over the years at this QTH simply because they dot the globe with their low powered one-way signals and are a challenge. Hearing a beacons’ very weak CW signal fading in and out with its’ short message, usually starting with a series of “Vs” followed by the call, then by info such as location, wattage, grid square is a timeless source of pleasure. There are literally hundreds of beacons to hear using your shortwave or ham radio, all coming in at different times of the day from places far and near. And there’s no need to be in the shack; check them out using a portable radio because when band conditions are favorable, you’re bound to hear them. And for those of you with RTL-SDR dongles, these miniscule radios are perfectly capable of receiving beacons and have the added feature of “looking” at that portion of the spectrum both via the 2-MHz wide spectrum display and accompanying waterfall image. These dongles are an inexpensive entry into HF/VHF/UHF listening and cover all modes. However they are not a plug ‘n play venture, you’ll need a computer, driver program, software to turn the dongle into an operating wideband receiver, patience learning the software, and a good antenna.

Typical “dongle” Software Defined Radio covering 24 – 1766 MHz.

Typical “dongle” Software Defined Radio covering 24 – 1766 MHz.

Screenshot of 10m beacon activity in right-half of waterfall on 6/22/15; VA3KAH was heard on 28.168 MHz.

Screenshot of 10m beacon activity in right-half of waterfall on 6/22/15; VA3KAH was heard on 28.168 MHz.

Most 10m beacons operate at low power, anywhere from 100mW to as high as 100W but generally operate in the 1 – 5W range using a variety of antennas, the vertical being the most popular. So in essence these beacons are not what you would classify as“big guns” and that’s the beauty of it all. They are an intriguing and challenging quarry to write into your logbook! While 10m tends to be more active during daylight hours and when sunspot numbers are good, this doesn’t mean that beacons will not be heard; a quick “sweep” of 21.1 – 28.3 MHz while you are in the shack or outside listening on a portable is always worth a check. Having a good pair of headphones will aid in hearing the weak ones.

Yaesu frg-7

My all-time favorite, the Yaesu “Frog 7” performs well for 10m beacon hunting.

To give readers some inspiration, below are some recent morning loggings using an AR-3000A and a 43 foot S9 vertical antenna. Band conditions were not the greatest, with most beacon stations fading in an out and propagation favoring Europe. Using a pair of headphones, logbook and pencil at the ready, it required sitting on some frequencies a few minutes as the beacon of interest faded in an out, until all the information was logged. Most beacons will begin their transmission with a series of “Vs” which helps to identify an active frequency. Some will send a long tone out first, allowing you to fine tune the station, while some start with a series of “dits” to get your attention. As you log these beacons you’ll see that each has its’ own agenda. For example, some only send their call sign. Others will send call sign, grid square, and power. Some even include a website or an address to send QSL information. If your code is rusty, no worries as most beacons send their call at least twice or thrice! 

Recent 10m Beacon Loggings de N2HUN

Date Time (GMT) Frequency Call QTH Comments
2/14/16 1423 28.166 XE2O/B Allende, Mexico 5W, EL05 (grid square), some QSB
2/14/16 1440 28.298 SK7GH Jonkoping, Sweden Very weak, heavy QSB, 5W
2/14/16 1447 28.223 KP3FT/B Ponce, PR Series of five “dits” precedes CW identification
2/14/16 1455 28.205 DL0IGI Hohenpeissenberg, Germany Long tone precedes CW identification, 48W
2/14/16 1500 28.173 IZ1EPM Chivasso, Italy Long tone before and after transmission, 20W
2/14/16 1530 28.242 IZ8DXB Naples, Italy Tone preceding transmission, JN70BU (grid square), 6W

My thanks go out to the Ten-Ten International Net ( ) for their excellent website covering the 10 meter band and to all those ham operators worldwide who took the time and energy to construct radio beacons for all of us to enjoy. Now, go forth and check out those beacons; don’t assume the band is dead, check out the beacon section of the band which will give you an indication of propagation conditions. Ten meters is very capricious and can open up at any time of the day, even late at night. And don’t forget to QSL the beacon operator! Good luck hunting down beacons and 73’s!

Thank you so much for this, Mario! Check out Mario’s other excellent guest posts by clicking here.