Tag Archives: Mystery Signals

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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Unidentified HF frequency hopping station

(Source: Southgate ARC via Mike Hansgen)

IARUMS reports on mystery frequency hopping station

IARU-R1 Monitoring System reports an intriguing transmission has been spotted giving short beeps exactly on each second, frequency hopping between 10108-10115 kHz and 18834/18899 kHz

One of the mysterious transmitters is located in the vicinity of Chicago, near the town of Aurora or Elburn, Illinois.

The International Amateur Radio Union Monitoring System (IARUMS) Region 1 November 2018 newsletter can be read at
http://www.iarums-r1.org/iarums/news2018/news1811.pdf

Reports of Amateur Band intruders can be logged on the IARU Region 1 Monitoring System Logger at
http://peditio.net/intruder/bluechat.cgi

Monitor the short wave bands on-line with a web based SDR receiver at
http://www.websdr.org/

IARU Monitoring System (IARUMS)
https://www.iarums-r1.org/

Have any Post readers heard this station?  I would love to hear a recording or see this station on a spectrum display.

Can you help Rick ID this mystery digital signal?

Ricks-Location

Photo from Rick’s location in Vernon, BC.

Many thanks to SWLing Post reader, Rick Slobodian, who writes to request help with the following:

Tecsun-PL-606I was on the beach at our lake, [where I was listening to my] Tecsun PL-606 receiver.

[On Friday, August 19, 2016 at 1800 UTC, I noted a] “beeper”: beeps at Hz repetition rate , does not appear to be data, it beeps for about a minute then there is a short data burst then beeping again for a minute or two.

This went on for over an hour.

Location of Vernon, British Columbia, Canada.

Location of Vernon, British Columbia, Canada (click to enlarge).

[The beeping covered] all frequencies between 13400-13800 kHz. [Then on August 20, it started at] start 1745 UTC and was no longer on 3400-13800 but now on
all frequencies between 12120 -12250.

What is it? [Take a listen:]

Click here to download a recording of the beeping.

My ham radio friend says there are a network of stations that send out pings that everyone in the group transmits and everyone receives. The signal strength and phase of the rx signal is correlated at each receiver station, to direction find some unknown station.

Was there such a thing during the cold war, and is it still around? What is this system and where can I find out more about it?

Thanks for your inquiry, Rick. This is outside the scope of what I understand on the HF bands, so I hope SWLing Post readers can chime in and offer suggestions.

Please comment if you can help Rick ID this transmission!