Oddity station Long Dashes, 20 March, 2020, 1435 UTC

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Jun 18, 2010
Mojave Desert, California, USA
In my log books are many entries for a signal I call "Long Dashes", the first entry with that name goes back to early 2013. I should explain that most of the signals I see repeatedly have some kind of name in my log, it just helps me remember them. If I know what the signal actually is then the name is whatever the signal is, but if I do not know what the signal is I make up a name that fits.

Long Dashes are, as the name says, a long dash. But, it is more than that, it has a few specific habits. Long Dashes has a dash length of 2.9 seconds. The first 200 msec of each dash contains some kind of modulation at 100 Hz. This dash is sent every 27 seconds on each frequency. This dash sequences through multiple frequencies, one dash on each frequency, with 0.1 seconds between each dash / frequency. The dashes start at the highest frequency in a given set and sequence downwards. The frequencies used vary, but fall within a set of specific ranges.

Long Dashes does not appear to transmit 24 hours a day, in fact it does not appear to transmit every day, but it is not uncommon for sets of frequencies to be in use for hours at a time, or it might be up on a given set for a few minutes and then switch to a new set of freqs.

There is a similar, but definitely different, signal I call the Pips Network in my logs that has similar habits, but much shorter pulses and typically far more frequencies. There is no doubt in my mind the two are unrelated, but may serve similar purposes.

I have a video of Long Dashes as seen between 1311 UTC and 1450 UTC on March 20, 2020, this might help to demonstrate what this signal does. In this time window it was active on 5 frequencies that I could find, 16199 kHz, 12472 kHz, 11920 kHz, 8994 kHz, and 6500 kHz. It is very possible that here were more frequencies in use that I never found, if so these were probably either above or below, or both, the 16199 kHz top end and the 6500 kHz low end.

Each cycle went like this: 2.9 second dash on 16199 kHz, 0.1 second delay, 2.9 second dash on 12472 kHz, 0.1 second delay, 2.9 second dash on 11920 kHz, 0.1 second delay, 2.9 second dash on 8994 kHz, 0.1 second delay, 2.9 second dash on 6500 kHz. 12.1 second delay, then start over on 16199 kHz. This 12.1 second delay would allow for the system to be on 4 more frequencies, however if they were active I never found them.

Video from March 20, 2020, here:

And another video below of the same signal on March 7, 2020, note that at that time I only found 3 frequencies in use, and only show reception of three of them. Up until March 13 the most frequencies I had ever logged in use was 4, however I believe that was just because I had never found the 5th freq. Every since finding the 5th freq for the first time I have found 5 in use any time I look.

Video from March 7, 2020, here:

Now, what is this signal? I don't know. Whatever it is, it has big reach. It is not unusual for this signal to be heard in North America, Asia, Australia, Europe, the Middle East, and South Africa all at the same time. I suspect it is some kind of propagation or ionospheric measurement tool, but that is strictly a guess based on the habits observed.

What say yee?

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