Data Transmissions in the CB band

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BM82557

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What was this sweeping signal?

Noticed this at 22:10 UTC sweeping from about 24 mhz to 26 mhz. In the attachment the vertical signal bar is at about 25.510 mhz. Signal visibily sweeped from lower mhz to higher mhz several times with increasing strength (lower track in the waterfall display is weaker than the upper track)



 

Token

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Noticed this at 22:10 UTC sweeping from about 24 mhz to 26 mhz. In the attachment the vertical signal bar is at about 25.510 mhz. Signal visibily sweeped from lower mhz to higher mhz several times with increasing strength (lower track in the waterfall display is weaker than the upper track)


This is called a “chirpsounder”. It is an atmospheric sounder testing propagation. They are located around the World and run by a variety of entities, from Universities to militaries.

Video examples here:
Sounder, Chirpsounder in ham 17M band, May 27, 2012, 1421 UTC - YouTube
Sounder, Chirpsounder in ham 20M band, May 27, 2012, 1456 UTC - YouTube


This is an image of one going from about 6600 kHz to about 28000 kHz. It stopped at 28000 kHz, but it started before the 6600 kHz shown here. They can run anything from about 2000 kHz to over 30000 kHz.
original.jpg



T!
 

br0adband

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Awesome, thanks for the info, it surely helps in figuring out just what the hell we're not only hearing but now seeing. Since I'm still pretty much new to SDR and this visual way of seeing the spectrum instead of just hopping frequencies till the receiver finds something to stop on, I myself just don't have that much experience with identifying a lot of stuff that exists out there. I too have seen those recently and it's pretty wicked when it happens: see activity along one side of the spectrum and zip, right across it goes, leaving me with the typical "What the hell was that?" reaction. ;)
 

BM82557

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This is called a “chirpsounder”. It is an atmospheric sounder testing propagation. They are located around the World and run by a variety of entities, from Universities to militaries.T!



Thanks for the explanation. As br0adbad stated there are many things that are now visible using SDR that I didn't even know were going on behind the scenes.
 

n9mxq

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Im using the DVB-T variety which has the R820T tuner. This one here: Amazon.com : RTL-SDR, FM+DAB, DVB-T USB Stick Set with RTL2832U & R820T. Great SDR for SDR#, HDSDR, and Other Popular SDR Software Packages! : Electronics

It will tune down to around 24Mhz before it drops out. I've successfully tuned 12m and 10m in the HF spectrum without an upconverter,which is in the mail. ordered it 8 days ago :(

Huh, guess I'll have to get one with the 820T (already have a E4000 model DVB-T).. Ya know, just because.. And I'm working on getting a converter also..
 

Tandom

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I remember R/C vehicles from Wal-Mart and Family Dollar use to operate around the upper 27mhz band. The little plastic controller would sometimes send tones and beeps to the vehicle to make it move. I don't know if this would cause noise in the 27-30 mhz area, or if this type of R/C is even still used today.
 
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