Mystery Data Burst?

[ARC5]

Hello, all.  I've heard this "mystery" signal around HF for years. 
I wonder if anyone knows what it is?
It sounds like this:
http://home.netcom.com/~arc5/pulses.wav
Here it a lot around the ham bands, especially around "certain" freqs.
Some have speculated that it's HF-DF stations sending data burst
to each other to calibrate for band conditions and increase accuracy.
Anyone have a real idea?

TNX OM ES 73 DE Dave AB5S

[Token]

Frequency?  Mode of operation you recorded this in?  There does not appear to be any usable data in this recording, just something breaking squelch.

At first glance this looks like 6 pulses, each 100 msec long, in groups of 2, with 20 msec between the pair and a pair every 900 msec.  But since the pulse is not actually represented, only the breaking squelch / change of AGC is shown, it is hard to be sure.

Try another recording, don't have the squelch on, use USB mode, and tune 1 kHz low.  This will increase the probability that something can be made of the recording.

HFDF stations do not link via HF, at least none I have ever heard of or worked at.

T!

[ARC5]

Thanks for your reply.  I should have been more clear; the audio
is a simulation of the sound, not a recording of the sound itself.
It appears at what seem to be completely random times.
I've gone weeks without hearing it at all.
But one thing:  When a ham frequency is "frisky" like 14313
used to be or 7200 now, or when the Mexican drug runners are
talking between 6.5 and 7.1 MC, I hear it much more often.
I will try to leave a laptop recording audio and try to catch a
"real" instance, but that will take some time.  Been a long mystery.

Thanks,
Dave S.

[Token]

Yeah, gonna need more data to come up with some kind of answer that might mean anything.

You might be hearing it at those times because that is when the band is more open, just a guess.

Could it be 4 or 8 burst instead of 6?

Some rough guesses to start with, and these are nothing more than WAGS until we have a recording, 4 burst might be the VIPIR sounder, 8 bursts might be HF-PANTHER.

T!