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Author Topic: Mystery Signal On Multiple Bands  (Read 1463 times)

Offline Warkite

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Mystery Signal On Multiple Bands
« on: May 22, 2014, 1413 UTC »
Hello All,

I've been seeing a strange signal showing up on multiple bands. I'm seeing this on the waterfall of my ANAN SDR. It is very strong from the Gulf Coast region of the US.

Listening on SSB (see attached video), it sounds like a low note on a big church organ and each block has a different note. The blocks last from 200 ms to 2 seconds and is about 10khz wide. Sometimes it's preceded by 3 continuous wave (CW) tones.  I've also heard it on my backup radio. A buddy across town has heard it so it's not some type of smart sensor at my location.

The frequencies I've seen it on are 11.4 Mhz, 13.8 Mhz, 19.3 Mhz, 27.6 Mhz among others. It's intermittent and frequency hops 50 or 100 Khz. It may also be different stations on nearby frequencies.

Here is a movie version of the signal:

https://drive.google.com/file/d/0B9ZaiT30jqAXNVZ0cnBuVlRjelU/edit?usp=sharing


Thanks for your help,

Warkite

Offline Token

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Re: Mystery Signal On Multiple Bands
« Reply #1 on: May 23, 2014, 1344 UTC »
Your video is of a radar, which specific radar is impossible to say with certainty, but quite possibly it is the JORN out of Australia.  Some radars are easy to identify with relative certainty, others not so much.

Keep in mind that all signals that you see like this are not necessarily radar, or at least radars intended to track man made items like ships and planes, some might be sounders (specialized ionospheric radars).

You will often find that these radars often have no set frequencies, what you find them on today will not be what they are on tomorrow.  They often hit around the same frequency ranges, but differing specific frequencies.  These radars generally have azimuthal control but no elevation control, and ionospheric propagation (skip) varies greatly.  The way these systems control what portion of the Earths surface they illuminate (and so the area they detect targets in) is by varying the frequency to take advantages of current, and ever changing, propagation conditions.

T!
T!
Mojave Desert, California USA

Offline Warkite

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Re: Mystery Signal On Multiple Bands
« Reply #2 on: May 23, 2014, 1439 UTC »
I suspected something like that as I saw a few cases of ionospheric sounder scans originating from them. It is surprising how prevalent these things are on the HF bands.

Thanks,


Warkite
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