Category Archives: Radio History

Help Brian identify this 1970s era interval signal

[Mystery solved! Click here to read the update.]

Many thanks to SWLing Post contributor, Brian (W9IND), who writes:

I want to thank you for stirring a memory that I never thought I’d relive – even though it still doesn’t solve the mystery of what the heck I was listening to in the first place!

Back in the early 1970s, I was a teenage SWLer with a curiosity for the worldwide signals that emanated from the speaker of my shortwave radio. Bitten by the SWLing bug after stumbling across Radio Nederland’s Bonaire relay station, I spent many a happy hour twirling the dial in search of fresh game to hear and QSL.

But on one such occasion (I’m going to guess it was in 1971), I was surprised and fascinated by what sounded like a snake-charming horn playing notes at random. Stranger still, the transmission would seemingly go off the air for a couple of seconds and then return to play the strange melody again. I chalked it up to one of the countless beeps, hums and other electronic noises that often appeared on utility frequencies in those days.

I never recorded it, I never had a clue what it was, and I never heard it again.

Until recently. On the Shortwave Radio Audio Archive.

A couple of weeks ago, while looking for old shortwave interval signals from the 1970s, I saw a recording marked “Unidentified interval signal 1” listed right after the interval signals of Deutsche Welle and Radio Nederland.

“OK,” I thought. “Sounds like a challenge. Maybe I can even help figure out what it was.”

Then it played … and I almost fell off my chair! I literally sat with my mouth open as the long-lost sounds of the “snake-charming horn” played again. Could it indeed have been an interval signal – and if so, for what station?

I wanted to contact the person who recorded it, but then I learned the sad news that Mr. Greg Shoom is no longer with us.

So I remain mystified, probably forever. But it sure was fun hearing that weird recording again! Thanks for the memories.

Let’s see if an SWLing Post reader can help, Brian!

I know of at least a dozen readers who are experts on all that is interval signals, so hopefully someone can listen and ID this one.

I’ve embedded audio from this SRAA recording below. Note that the unidentified interval signal can be heard between time marks 1:27 – 2:07 in the following recording:

Can you positively ID this interval signal?  If so, please comment!


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Dan shares memories of work at KGEI

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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“German Archaeologists came across a Russian spy radio”

Photo: Jürgen Vogel / LandesMuseum Bonn via the Southgate ARC

(Source: Southgate ARC via Jake Brodsky, AB3A)

Not an everyday find: Archaeologists from the Rhineland Regional Council were amazed when they came across a Russian spy radio instead of Roman traces in the Hambach open-cast mine during excavations. Hidden in a large metal box.

“When the box was opened, it hissed,” Dr. Erich Claßen, head of the LVR Office for the Preservation of Archaeological Monuments in the Rhineland, told journalists. In the container: a Soviet radio type R-394KM, code name Strizh, a digital HF spy radio.

It was developed in the early 1980s in the Soviet Union (USSR) and used by the countries of the Warsaw Pact in the final phase of the Cold War. It was the last model before the fall of the Iron Curtain in 1989 and the collapse of the Soviet Union in 1992.

The device has a digital news system and a digital frequency display. It was used by agents abroad as well as by special units and was available with Russian or English text on the front. The spy version is known by the Russian code name “Strizh” (English: Swift).

In the LVR-Landesmuseum in Bonn there is currently not only the mysterious radio to see. Under the title “Gods, Graves and Agents”, spectacular finds from the year 2019 are on display until 29 March:

https://bodendenk
malpflege.lvr.de//de/aktuelles/veranstaltungen/AusstellungAiR2019.html

73

Tom DF5JL

Click here to read the full article at the Southgate ARC.

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Former KGEI transmitter building sports callsign once more

1941: KGEI’s reinforced concrete transmitter building near Belmont. Built to withstand bomb or earthquake. (Source: TheRadioHistorian.org)

Many thanks to SWLing Post contributor, Tracy Wood (K7UO), for sharing the following article from The Daily Journal. Tracy’s notes follow this excerpt:

KGEI, a shortwave radio station in Redwood Shores that was the only voice from home for GIs in the Pacific during World War II, has its call letters back.

The letters on the front of the building located off Radio Road were covered up decades ago by a church that took over the station’s transmitter building, now part of Silicon Valley Clean Water.

“I am happy to report that we have uncovered the letters on the building,” said Teresa Herrera, manager of the wastewater treatment facility. “I think it looks great!”

Herrera said she had no idea of the building’s history until the Rear View Mirror brought it to SVCW’s attention. No extra money was needed for the restoration because the building was due to be painted.

“The letters were just as they were when the concrete forms had been originally removed in the 1930s,” said construction manager William Tanner.

Still, there is no plaque to remind the few visitors to the area that KGEI, the GEI standing for General Electric International, played an important role in World War II. Among other accomplishments, the station broadcast Gen. Douglas MacArthur’s “I have returned” speech that fulfilled his promise to return with victorious American troops to the Philippines, occupied by Japanese forces since 1942.

“The First 24 Hours of War in the Pacific,” a book written by Donald Young, underlines the importance of KGEI. It also reminds readers how successful Japanese forces were during those 24 hours in attacking Malaysia, Hong Kong, the Philippines, Wake Island and Guam, as well as Hawaii.[…]

Read the full article at The Daily Journal.

Tracy also shared the following notes:

During my youth I often listened to KGEI, both in Oregon and Bolivia. I got to visit the station in the 80s. I remember their teletype spewing paper for the long-form newscasts… The old 50kw GE hummed away.

The parasitic oscillations would actually form audio that you could hear in the studio/transmitter room. The 250 kw unit was tucked away… kind of hard to see.

KGEI was an important part of LATAM radio history.. the Cuban Missile Crisis, earthquake outreach to Nicaragua, etc.

Cheap clock radios could receive KGEI in Oregon when the 250kw unit was blasting to Asia.

“Mission Engineering” 250kw beamed to Asia on 5980 could often be heard with Chinese and Russian slow-dictation programming… trying to overcome the Cold War ban of Bibles in the Communist countries.

If you can find a copy of the book “Sky Waves” that has a complete history of FEBC and some more details about “La Voz de la Amistad,” the Voice of Friendship KGEI.

Thank you so much, Tracy, for your notes and insights!

I just found a copy of the 1963 book Sky Waves by Gleason H. Ledyard as a free download via the American Radio History website. Click here to download the PDF.

I imagine other SWLing Post readers remember KGEI as well. If so, please comment!

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The secret role of Beaumanor Hall

(Source: Southgate ARC)

The Leicester Mercury reports on the top secret wartime listening station role of a Leicestershire mansion

As we approach the 75th anniversary of VE Day in May, a Loughborough Library Local Studies Volunteer (LLLSV) tells the fascinating story of Beaumanor Hall’s crucial role in the Second World War.

Many readers may not know, but Beaumanor Hall was the site of a vital wartime intelligence service, namely the War Office “Y” (wireless) Group or W.O.Y.G.

The top secret “Y” Group was part of M18 Wireless Intelligence and Beaumanor was a highly-strategic “Intercept Station”, concerned with monitoring the enemy’s main channels of wireless traffic and communications.

The “Y” Intercept Listening Service operated from 1941 to 1945 and its wartime activities were as top secret as those at the Code and Cypher School at Bletchley Park.

Click here to read the full story at The Leicester Mercury.

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A Look Back: Memories of the Panasonic RF-2200 and its sibling, the National Panasonic DR22

Many thanks to SWLing Post contributor, Mario Filippi (N2HUN), for the following guest post:


A Look Back: Memories of the Panasonic RF-2200 and its Sibling, the National Panasonic DR22

by Mario Filippi, N2HUN

All photos by author unless otherwise noted

One of the preeminent AM/FM/SW portables of all time is the venerable Panasonic model RF-2200 receiver that was sold in the USA starting in the mid-1970’s for around $165.00 US.

Weighing in at a hefty 7 pounds, 13 ounces and vital statistics of 12” x 7” x 4” it came equipped with a robust shoulder strap to schlep from the radio shack to alfresco listening sites and was basically a completely self-contained entertainment center for the radio enthusiast.  My first RF-2200 was purchased in the late ‘70’s from Grand Central Radio Shop in New York City, now just a memory and long gone, but back then they sold a bevy of shortwave and ham radio equipment.

Photo 1. Author’s favorite portable of all time, Panasonic RF-2200

It was love at first sight when I saw the RF-2200 in the store’s gleaming glass display case way back when. The ‘2200 possessed all the bells and whistles to guarantee a good time for the SWL such as a rotatable ferrite AM broadcast band antenna, BFO (Beat Frequency Oscillator) for SSB reception, AM /FM/SW (3.9 – 28 MHz) bands, a D’Arsonval “S” meter that doubled as a battery status indicator, large four inch front mounted speaker, switchable coarse/fine tuning speed, base/treble/RF gain pots, 125/500 kHz crystal markers to calibrate the VFO, wide/narrow bandwidth switch, dial/S meter lights, earphone/recorder jacks and telescopic antenna for SW and FM. Plus it sported the renowned Panasonic trademark.

Photo 2. RF-2200’s rear: exposed battery compartment, screw connectors for external antenna, AC plug lower right. Rectangular earphone storage compartment is above batteries. Battery cover’s gray foam pad is dry rotted and needs replacement.

Part of the 2200’s ample avoirdupois can be attributed to the unit’s four “D” battery power plant, but Panasonic also supplied an AC cord to plug into the house mains and an earphone (located inside the battery case).  It runs forever on those four stout dry cells, one of the many positive features of this vintage gem.

Back in those days portable radios generally were not judged and valued based their diminutive size and weight but on the array of features geared to the end-user. Front panels were festooned with an array of controls rivaling an aircraft’s cockpit.  Knobs, analog dials, meters, large front-mounted speakers, switches and lots of black plastic were the order of the day. These all contributed to the beauty and practicality of portable shortwave radios back then.

One thing missing though was built-in memory channels; those existed in the operator’s brain and not yet delegated to memory chips.

Photo 3. Pack of four “D” cells, at 1 lb 4oz, weighs more than some of today’s portables!

One of the features long gone and missing in modern receivers these days is the “recorder out” jack that looks identical to an eight-inch earphone jack and yes the ‘2200 has one. It was used to plug in a tape recorder to memorialize an op’s favorite radio show. Of course back then there were many more shortwave stations broadcasting.  Gone also are those tiny incandescent bulbs, sometimes described as “grain of wheat” lamps that were used on S meters, dials, etc. The RF-2200 sports ample illumination for the S-meter and tuning dial which makes it a perfect bedside table radio for late night DX’ers and insomniacs.

Speaking of DX, the ‘2200’s rotatable AM ferrite antenna is one of the main virtues this radio possesses.  As an avid AM DX’er and faithful disciple of AM radio in general, the ‘2200’s rotary directional antenna nulls out noise and routinely pulls in stations as far away as Nashville (WSM), Chicago (WBBM), St. Louis (KMOX), Atlanta (WSB), Boston (WBZ) and Toronto (CJBC) when the sun goes down. Look closely at the antenna mount’s base and you’ll even see compass-like degree markings that’ll help when retrieving a favorite local or DX AM station.

Photo 4. Operating manual copy is available on-line

Shortwave coverage is approximately from 3.9 – 28 MHz as per the service manual, but I’ve checked the actual coverage of my unit using a calibrated service monitor and found it to be 3.47 – 28.9 MHz which makes sense since I’ve tuned to W1AW’s code practice on 3.581 MHz with no problem and have also heard the Volmet station on 3.485 MHz. That’s good news for hams wanting to receive 80m CW.  It gets a bit tricky though using the fine tuning option for CW hi hi.

AM broadcast band coverage is only from 525 – 1610 kHz as per the specifications; the AM band had not yet been extended to 1710 kHz at that time.  The ITU approved the extension in 1988. With that in mind I wanted to determine what the actual band coverage of my unit was. Again, using an IFR service monitor it was found to be from 514 – 1720 kHz; that’s good news for those who listen to stations at the top of the band.  It also explains why I can hear YWA, a non-directional radiobeacon (NDB) from Toronto, Canada just below the AM band on a frequency of 516 kHz. If you own a RF-2200 or DR22 tune to the bottom of the AM band and listen for it. You may also hear the warbling sound of NAVTEX stations on 518 kHz.  Switch on the BFO and wait for dark, you might get lucky like I have.

My apologies for not being an FM broadcast band listener so all I can state is the few times I’ve listened it sounded absolutely great.  The specs state a FM broadcast band frequency range of approximately 87.5 – 108 MHz. Mine measured from 86.8 – 108.9 MHz but I’ve yet to realign my unit so these ranges may vary among the population.  Note that I have undertaken the labor intensive task of aligning my National Panasonic DR-22 which is almost the exact same unit as the ‘2200. You can search this blog for my results that were kindly published by Thomas previously (click here to read).

Photo 5. Side by side comparison.  Panasonic RF-2200 on left, National Panasonic DR22 on right.

For those not aware, the RF-2200 was also marketed in Europe as the National Panasonic DR22 and in other parts of the world as the Cougar 2200. My DR22 was an eBay purchase, and that’s the best place to find either model.

DR22s are rather rare compared to the ‘2200 though. First off, one of the major differences with the DR22 is that it runs on either 110 or 220V, and that’s accomplished by a switch on the back of the unit.

DR22 runs on 120 or 240V via switch on rear panel

The DR22’s front panel stenciling is slightly different too, as shortwave bands are labeled “KW 1 – KW 6” in addition to “SW1 – SW6”.  Not sure what “KW” means though. Perhaps some reader can enlighten us.

Well, that’s about it, if you want a RF-2200, or DR22 then window shop on eBay.  Lately they have been selling from $40.00 US (parts only) to $455.00 for pristine units. That’s a pretty wide price range and even I’m surprised at the high prices being gotten for clean units.  All I can say is that the two I have now are staying right here in the shack with me.

Thanks for reading and 73’s.


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Thank you so much for sharing this excellent post, Mario. Like you, I’m a massive fan of the Panasonic RF-2200; in fact, I own two of them! It is, in my opinion, the best AM/MW portable ever made. 

Post Readers: Any other RF-2200 and DR22 owners out there? Can anyone explain why the DR22 labels shortwave bands as “KW1 – KW6”–?  Please comment!


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Radio Waves: WBCN, Reactions to AM Digital, More KPH, and Cereal Box Telescopes

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, Mike Terry, Troy Riedel, andGrant Porter for the following tips:


WBCN history reveals revolutionary power in local radio (Boston University News Service)

SOMERVILLE – What started as a midnight to 6 a.m. slot on a failing classical music station, became the voice of a generation in 1970s Boston. Now, more than 50 years after WBCN sparked a “revolutionary new experiment in radio,” the bygone rock station is still making waves.

The 2018 documentary, “WBCN and The American Revolution,” tells the origin story of Boston’s first rock and roll station through a combination of rock hits. Never-before-seen photos, videos and interviews with some of Boston’s most beloved radio hosts, were greeted with cheers at the Somerville Theatre screening Thursday night.

Bill Lichtenstein, who began volunteering with WBCN at 14, directed and produced the film. After crowdfunding and a decade in the making, it has been touring independent theaters and festivals across the U.S. for the last year and a half.

WBCN was grounded in good music. Founded by Ray Riepen, owner of South End music venue The Boston Tea Party, WBCN introduced voices like The Velvet Underground, The Who, Bruce Springsteen and Led Zeppelin to the city, and quickly found a home in Boston’s huge student population. Within three months, the station, run by amateur hosts and young volunteers during classroom breaks, was playing 24 hours per day.[…]


“It Will Make Millions of Receivers Obsolete … This Is Needless” (Radio World)

What people are saying to the FCC about all-digital on the AM band

Radio World is providing an ongoing sampler of comments of what people are telling the FCC about its proposal to allow U.S. stations on the AM band to switch voluntarily to all-digital transmission. Here are more in the series:

Kirk Mazurek told the FCC that he is an avid AM listener who has “invested time and money in equipment towards my hobby as many others have. If this proposal goes through it will make the millions of receivers obsolete requiring the purchase of new equipment. This is needless, there are a lot of people who have vintage radios and a lot of them have been restored. This proposal would make them useless. I urge you not to ratify this proposal.”

Mark Wells raised concern about interference from digital to analog signals on the same channel. “This is especially applicable at night when one is listening to distant stations in out-of-state markets, he wrote. “For example, clear channel stations WBT in Charlotte and KFAB in Omaha are both on both on 1110 kHz. Let’s say one switches to digital, and one does not. As it is they both may fade in and out as the atmosphere does its nightly tricks, but the signals remain mostly useable. But, if one is digital and the other analog would it not ‘blank out’ the analog station?”[…]


Podcast features Coastal Radio Station KPH (DitDit.fm)

There was a time when the airways bristled with Morse Code. There were commercial radio stations all around the world whose business was sending and receiving Morse Code messages to ships at sea. Coast station KPH, located at Point Reyes National Seashore near San Francisco, is one of those stations. Richard Dillman was there in 1997 when KPH sent it’s last message and closed it’s doors. It was the end of the line for the men and women who had spent their careers sending Morse Code to ships at sea. There was nowhere else for them to go…

Two years later, Richard Dillman with a group of volunteers returned to KPH and put it back on the air. Listen as Richard tells us about the future of Maritime Morse Code Coastal Station KPH!


A hydrogen line telescope made from cereal boxes and an RTL-SDR (RTL-SDR.com)

SpaceAustralia.com have recently been hosting a community science project that involves encouraging teams to build backyard radio telescopes that can detect the arms of our Milky Way Galaxy by receiving the Hydrogen line frequency of 1420 MHz.

This can be achieved at home by building a horn antenna out of cardboard and aluminum foil, and a feed from a tin can. Then the Hydrogen line and galactic plane can be detected by using an RTL-SDR, LNA, and software capable of averaging an FFT spectrum over a long period of time.

While most horn antennas are typically made from four walls, one participant, Vanessa Chapman, has shown that even trash can be used to observe the galaxy. Vanessa’s horn antenna is made from multiple cereal boxes lined with aluminum foil and an old tin fuel can. The boxes are held together by some string and propped up by some sticks.

With her cereal box horn antenna combined with an RTL-SDR Blog V3, and an RTL-SDR Blog Wideband LNA, Vanessa was able to use software to average the spectrum over time as the galactic plane passed overhead, revealing the Hydrogen line peak and corresponding doppler shift from the galactic plane.[…]


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