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On our quest to solve UNID utility signals, SWLing Post contributor David Crawford, is asking for help again to ID yet another interval signal. David writes:
Here’s yet another memorable utili-tune from the deep archives here, again not my recording, origin uncertain.
This one has a date, time and frequency on the filename [19670811-2347-15910-VM unID] and therefore would have been 1967. I heard this one myself occasionally also, which would have been sometime during the mid-to-late 1970s. It would have overlapped with the same time period during which CTNE was using the 14985 kHz tune previously provided, so despite the broad similarity I would assume it wasn’t them. Unless of course they used different tunes for different circuits:
Readers: Can you positively ID this interval signal? If so, please comment!
This is the “interval signal” (more accurately, a placeholder with a musical station identifier) for the Compañía Telefónica Nacional de España (CTNW) from Madrid, Spain.
They were a point-to-point HF radiotelephone terminal that provided overseas telephone and telegraph services in the days before satellites became common.
As a young SWL, I would receive all manner of strange musical identifiers for these utility stations. Most of these HF telecommunication services had gone to satellite by the early 1980’s. The HF bands were chock-a-block with signals, whether they be broadcast or utility services.
Glad to help!
To verify his claim, Dean shares the following embedded audio file made by Willi Passmann in the mid 1970s (via the excellent UtilityRadio.com website):
Well done, Dean! Thank you once again for coming to the rescue!
In case you didn’t know, dear readers, Dean Bianco is a force to be reckoned with in the shortwave radio world. 🙂 This year, he won the 3rd Annual Fest Trivia Quiz at the 2020 Winter SWL Fest! An impressive accomplishment, indeed. Not only that, but Dean’s an incredibly nice guy, great friend, and always willing to help out those new to the hobby!
This month, SWLing Post contributor, David Crawford is asking for help to ID another interval signal which likely belongs to a utility station. David writes:
In follow-up to the La Habana utility mystery, here’s another one from the same era, 14985 kHz or thereabouts. Somewhere along the line I came to the conclusion that it might be El Salvador, but I don’t remember what led to that. The [recording embedded below] isn’t my own recording of it.
The tune is composed of individual DTMF tones, and when I was a bored youth I discovered that it could be played on an AT&T desk touch tone phone by pressing two keys at a time to remove the second tone. This one would repeat for hours at a time, interrupted by manually patched telephone calls.
Readers: Can you positively ID this interval signal? If so, please comment!
Yesterday, we published a post asking SWLing Readers to help Brian (W9IND) identify an elusive interval signal (click here to read that post).
We received dozens of replies–thank you so much!
Many readers immediately identified the tune as some sort of utility station placeholder for Point To Point communications. Turns out, they were correct.
Many thanks to Dean Bianco who was the first reader to solve the mystery.
Dean discovered that the interval signal was for the Voice Mirror of the PTT Habana, Cuba.
Dean verified it via Rainer Brannolte ‘s excellent website, UtilityRadio.com.
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.
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?
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!
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.
Many thanks to SWLing Post reader, Rick Slobodian, who writes to request help with the following:
I 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 (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.
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!
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