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Loggings => Utility => Topic started by: ka1iic on May 11, 2013, 1917 UTC

Title: signal on 22820khz
Post by: ka1iic on May 11, 2013, 1917 UTC
'swisher' type signal on 22820 khz at 1827utc

audio file at:


First minute is on LSB while the second minute is on USB.

73 vince ka1iic _._
Title: Re: signal on 22820khz
Post by: Token on May 12, 2013, 1854 UTC
'swisher' type signal on 22820 khz at 1827utc

audio file at:


First minute is on LSB while the second minute is on USB.

73 vince ka1iic _._

“Page not found”, but that is OK, I think I know the signal you are talking about anyway.

This signal is a bit of a mystery.  At one time several listeners in the community thought they had a good grip on where it was from, and a couple of good ideas about what it might be doing.  But then information came to light that muddied the water a bit more.  Just a note, while exactly what it is may be difficult to say it is as close as possible to say it is certainly NOT a radar, as has been suggested on one forum.

First, lets say the frequency is actually 22819 kHz USB.  Yes, for those swept signals you could go with center frequency and that would be near 22820 kHz (typically ~22820.5 kHz c/f for the sweeps), but those swept signals are not the only things you will find from this source.  And for some of the other signals (and sometimes the audio noise on the transmission) you can see that the transmitter is indeed tuned to 22819 kHz and in USB mode.

22819 kHz is not the only frequency you will find these signals on, I have found them on 14756, 16926.5, 16929, 17299, 17383, 19281.5, and 22819 kHz.  I have heard of other freqs but have not captured those others myself.  Sometimes ALL of these frequencies are active at the same time, and sometimes all of the data on each freq are in sync, other times there is individual data on each freq.  The 16929 kHz signal is always in sync with the 16926.5 kHz signal, and might be a spur that helps indicate the transmitter is indeed in USB mode.

The swept signal is not the only kind of signal you will find on these freqs.  At various times there have been sweeps of different rates, there is often a drifty MFSK-like signal, and occasionally a few QPSK like signals.

The swept frequency is not an honest linear sweep, it is actually a stepped signal.  Since I cannot get your recording to play I cannot tell you which you are hearing, but I have heard sweeps with anything from 16 to 64 steps, with 32 being the most common that I have seen.

Here is the signal on 19281.5 kHz.  Also a max hold image of the 32 steps in this particular version.



WPG in Indiana is licensed for all of these frequencies and is a very good candidate for the source of these signals.  However these signals were first thought to be WLO and Swisscomm sourced.  At various times on each of these frequencies I have gotten good bearing cuts to both WLO and WPG locations.  European listeners have reported bearings consistent with HEB Swisscomm.  So, possibly there is more than one source associated, although WLO does not appear to be licensed for these freqs.

The swept signal has made for interesting monitoring in the past.  Sure, it is a boring sweep that could drive you brain dead in short order.  However, occasionally you can get both long and short path on these signals.  And when this happens on the swept signal it is fairly easy to calculate an approximate range to the source.  Combine said approximate range with a bearing cut and you get a specific geographic area that might be the source.

Image below shows the short and long path signals, and the delta between them (roughly 115 millisec).



In the above case the range is consistent with either WLO and WPG (by chance the range to each is about the same for my location) but the bearing was squarely on WLO, in Mobile, Alabama.

Title: Re: signal on 22820khz
Post by: ChrisSmolinski on May 12, 2013, 1940 UTC
I'm hearing a sweeper on 22819u at 1938z. About an S4 signal.

I also have something on 17299, but it seems to be stepping at a very slow rate, perhaps 2 or 3 per second?
Title: Re: signal on 22820khz
Post by: Token on May 12, 2013, 2115 UTC

The 17299 kHz is the "drifty" stepped signal is the one seen most commonly of late.  Sometimes it will be the same stepped sig on all freqs, sometimes each will be independant.  One time I saw the stepped signal and a sweeper on the same freq at the same time, but mostly they do not mix.

Here is an example of the stepped signal on multiple frequencies, all in sync.  I have shifted each tuned freq slightly so that each is on a seperate audio shift.


Title: Re: signal on 22820khz
Post by: cmradio on May 13, 2013, 0307 UTC
Here's the good link:

Title: Re: signal on 22820khz
Post by: ka1iic on May 13, 2013, 1438 UTC
WOW!  Thanks for all the good info... :-) Token....  (Do you have a book... maybe huh huh?)

As for the who what or where... all I can say is 'Shades of Vint Hill Farms at Warrington, VA' <hi hi>

I'm hearing the signal this morning (1425 utc - 05/13/2013) but very weak... slightly over the S3-S4 noise level.

This one will be on my watch list for sure.

QUESTION:  Whom has the best up to date audio files on this different 'sounds' on the bands. I admit I am playing catch up on this point for sure.

I haven't done much listening since the shut down of the OTHR site in Moscow Maine...  Visited the site after the shut down (unofficially) just to get a good look at the antennas.  Got to talk to many of the local folks up there about the station and most all of them agreed they were glad to see it go because now they could get to watch TV and listen to AM/FM again ;-)

Word has it one of the local Native American Tribes wants to buy the land and use it for a wind turbine farm for electricity.  Great location for that because the wind doesn't blow it sux...  ;-)

TNX AGN and 73
vince ka1iic
Title: Re: signal on 22820khz
Post by: Token on May 13, 2013, 1613 UTC
Thanks to cmradio I got the sound to play, and that is the same signal I suspected it was.  However this appears to be the non-stepped version of the signal.  You will find many odd signals on the associated set of frequencies.

The non-stepped version is also running today.  Right now (edit, not now, while writing this the Sun burped an X2+, and I have nothing at all on HF right now) I have the sweeps on 22819 kHz, the drifty MFSK on 14756 and 16926.5 kHz (not synced today, yesterday was synced), and nothing so far on the rest of the freqs.  I noticed these freqs fire up about 1330 UTC today.

As for a book the best I have seen is “Technical Handbook for Radio Monitoring HF”, but that will not have this signal in it.  It will have descriptions of many of the other signals you run across on HF in it though.

For audio files or descriptions of modes there are several sources.

I keep meaning to put up more examples on my YouTube channel, but so far only have a few up: