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HF Beacons / Possible new'ish beacon on about 4096.39 kHz
« on: August 20, 2021, 0017 UTC »

I have been seeing what may be a beacon on about 4096.39 kHz.  I have seen this for several months, possibly over 6 months (will have to check recordings to confirm) and it feels / looks / acts like a possible beacon.  But I am not sure, and if it is not a beacon then I do not have a good guess as to what it is.

I have never gotten this signal very strong, so I still have a lot of questions about it.  The following are approximates, since I have yet to get a good enough SNR on the signal to confirm some of them.

The freq is about 4096.39 kHz and appears stable, the signal may be about 34 Hz wide, and could be an approximate 22 Hz shift FSK.  I cannot confirm it is FSK, but it sounds and looks like it could be.  And the signal certainly has some kind of width to it, but again, I have not had a good enough signal to get much detail.  I have been waiting to get a good sig before reporting this, but it seems I may never get a decent signal on it so I thought I would put it out for others to keep an eye open.


Chinese (Tawainese) numbers station V13 (New Star Broadcasting) on 8300 kHz, H3E mode (USB + carrier), 1300 UTC, June 5, 2021 with its normal programming.

Carrier came up at 1300z.

I have this frequency in my logs for V13 in 2013 and 2014, so it is not new for them to use this freq, but I do not believe they have used it recently.



I have put up a few new videos on my YouTube channel, today they were all associated with the US military, USAF operated, HF-GCS (High Frequency Global Communications System), including what might be the last SkyKing transmission and a rather lengthy EAM.

For those not aware, the HF-GCS appears to have stopped sending SkyKing messages in late 2019.  Other message types have continued to be used as before, but it appears that possibly there are no more SkyKings being sent.

What I can say for sure is that there have not been any SkyKings recently reliably reported in the regular forums and mailing lists.  There have been some reported overall (such as on YouTube), but on further review of recordings/descriptions, etc, they were either definitely, or probably (in the case of no recordings) not actually SkyKings, but rather miss-identified EAMs.  I have not heard any SkyKings myself since October of 2019, and while I don't spend a great deal of time monitoring the HF-GCS, I typically would hear several a month prior to that date.

This is my last recorded SkyKing, and I have not yet seen a confirmable more recent recording:

Only time will tell, but has the SkyKing message format on the HF-GCS gone the way of other Cold War signals?

A rather lengthy EAM, of 164 characters.  To be sure, I have heard longer EAMs (the longest I have completely recorded is 278 characters, but I have heard the tail end of one over 300 chars), but this is definitely longer than average:

And a recent format SKyKing transmission from a couple years ago.  I included this video in the channel only because tomorrow I will release a video of an older format SkyKing, a format that they stepped away from in about 2016.


I have put up a new video on my YouTube channel, this one is of the Chinese oddity station MC03, the Morse code sister station to VC01.  This outlet of MC03 appears to have a very chirpy transmitter, and I have heard it (MC03) broken like this on several frequencies for more than 6 months.

This station appears to carry traffic very similar to VC01, and is also assumed to be related to air defense or air tracking.  In the video I annotate a couple minutes worth of the changing data, including time tags.

I find the time tags interesting.  There is one official time zone in China, Beijing Time (UTC +8).  However the time tags appear to be UTC +7, which would be Kansu-Szechuan time.  I have seen this pretty regularly with MC03, although I have also seen other time zones in use.  I assume I hear different time zones depending on where the node I am then hearing is located.  But why don't they all use BJT?



Spy Numbers / New video up, Chinese oddity station VC01
« on: April 24, 2021, 1740 UTC »
I have put up a new video on my YouTube channel, this one is the Chinese oddity station VC01.

For those not familiar, VC01 is also called the "Chinese Robot". It is a female voice, machine generated but possibly human recorded, reciting strings of numbers. It is at a very fast rate, too fast for reliable human interpretation. Absolutely the numbers are understandable, but for a human to reliably transcribe the numbers for extended periods is probably not realistic.

The station has been observed for at least a couple of decades, and is presumed to be related to air defense tracking. It has a sister station, assumed to be the same tasking, in Morse code, called MC03.



HF Mystery Signals / MOVED: UNID 4724 KHZ
« on: February 15, 2021, 0017 UTC »

HF Mystery Signals / MOVED: UNID 10340.10 KHZ USB
« on: December 13, 2020, 0456 UTC »

Spy Numbers / South Korean V24 may be inactive since late Sep, 2020
« on: November 29, 2020, 2346 UTC »
I have not been doing much radio stuff recently, but I have been doing my scheduled and programmed recordings and spectrum captures.  Those go on automatically as long as the hardware is turned on, and it has been on 24/7 even if I have been doing other things.  For V24 I capture and chart signal levels on all known past V24 freqs, including freqs they have not used in years, and record IQ files of scheduled transmission windows plus a bit more spectrum just in case.

Today I sat down to update the V24 schedule, which I last updated in March of 2020.  To do that I basically played back all the recordings and spectrum captures since March during the time period of 1000 to 1700 UTC daily.

It turns out V24 has not transmitted, to the best of my knowledge, since late September.  In September V24 made two of its nine schedules, or 6 of a possible 27 transmission.  It transmitted on 6215 kHz, on days 5, 7, and 9, at 1500 UTC each day, and it transmitted on 4900 kHz, on days 23, 25, and 27, at 1530 UTC.  So the last V24 transmission I am aware of was September 27, at 1530 UTC, on 4900 kHz.  And for several months prior to that it was at a much lower than normal rate of activity.

Of course there are several possibilities, the simplest is they may have shifted to a new schedule with new times and frequencies I have not captured.  Or they may have just taken one of their unexplained pauses.  In 2015 V24 did not transmit from 16 June to 26 November, one theory is that they changed transmitter facilities during that time period.

So, is V24 gone?  Or is it just taking a rest?  Or did COVID slow it down?


HF Mystery Signals / MOVED: STANAG on 3805?
« on: August 12, 2020, 2256 UTC »

So far UNIDed on 6926 kHz USB, started about 0225 UTC, 27 April, 2020.

S8 or a bit better into the Mojave Desert of California.

I did not know the first song played, but the second, at 0229 UTC, was "Wake Up" by Rage Against the Machine.


So far UNIDed station on 6950 USB.  Possibly heard an ID at 0353 UTC, but was not able to understand it.  Either the ID was over processed or the audio is a bit hot.

ID at 0357 UTC, sounded like Undercover Radio


This is an oddity on shortwave that I don't think I have seen before.  If it is common then somehow or another I have missed it.

About 0420 UTC, 03 April, 2020, I noticed what appeared to be a DSB transmission on 9024 kHz.  DSB is not a commonly used mode these days, so I looked a bit closer.

The signal did appear to be DSB, it also appeared to be a repeating audio loop.  About every 21.6 seconds (start to start) the loop repeated, with about 1.6 seconds pause between audio segments.  The audio was not understandable, either it was distorted, processed in some way, or encrypted.  Longer observation showed that every 11th repeated segment included a longer pause, about 3.1 seconds.  This made a repeating cycle of 11 segments about every 239.6 seconds.

Every segment transmitted appeared identical.  Just the same 21.6 second segment (time includes the audio pause) over and over, with every 11th including an increased length pause.

I have uploaded a video of this signal to my YouTube channel.  If you watch the video I include spectrograms of the audio loops, and visual comparisons of multiple examples.  I also demodulate the signal using multiple modes, USB, LSB, AM, and NFM, to show the sound in each mode.  And the last minute or so of the video is the signal demodulated with LSB in the left audio channel and USB in the right audio channel, for comparison.

Video here:


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