What's that strange sound on CG 12?

[davidmensing]

In the Rochester, NY area on Coast Guard channel 12 (156.600) I have been hearing a very strange sounding transmission from time to time. It sounds like scrambled voice communications but I can't be sure. Does anyone know what these transmission are or where they might be coming from?

 

[DaveNF2G]

There is a digital mode called AMTS that can be used on the marine channels. I've heard that it is in use by some commercial operators on the Great Lakes on channel 17. Maybe that's what you're hearing.

It could also be a signal that is actually being transmitted on some other frequency but which your scanner is processing as a 156.6 MHz signal for some reason.

 

[kb2vxa]

Hi David and all,

Without a sample it's impossible to take even an educated guess at what that "very strange sounding transmission" may be. I can tell you one thing however, the government including the Coast Guard has been using 3DES encryption for just about 20 odd years now. That sounds like a hiss, white noise similar to dead air with the squelch open followed by a very short high pitched beep.

 

[davidmensing]

Warren,

Funny you should mention the need for a sample of the transmission. Just this weekend I recorded about 1 minute of audio from these strange transmissions.

http://home.rochester.rr.com/dbmensing/CG12-MysterySounds.mp3

Give a listen and see what you think.

-Dave-

 

[DaveNF2G]

I've never heard anything like that sound. It obviously has a voice component, so if it's some form of encryption it would be of limited effectiveness over the long term.

 

[kb2vxa]

Weirdest damn thing I ever heard! Frankly I haven't a clue, that mess would take a specrographic analysis far beyond anything I'm capable of doing just to figure out it's basic components. Frankly it may not even be FM, I can't run an RF spectrogram from here, sorry. (;->)

I'll take a wild guess, aliens. Your tin foil hat may not protect you from the mind probes, I'm feeling a little strange just from listening to to bft shmjer fhkiff... *#b

 

[gcgrotz]

Wasn't it that large creature that looked like a praying mantis?

Was that recorded from an FM receiver (aka scanner)? I would love to hear it in USB maybe.

 

[bravo14]

I listen to the file and sounds like Drunk Alliens to me. I have no idea what that sounds it but weird.

 

[n2nov]

Aren't they using a VINSON derivative? I know that USCG also uses P25/encrypted.

 

[AuntEnvy]

I listen to the file and sounds like Drunk Alliens to me. I have no idea what that sounds it but weird.

I bet Riley Martin would know.

 

[eorange]

Wow, I've never heard that on 156.6, which I monitor all the time. The chirpy part reminds me of a sped-up ALE.

 

[bravo14]

I bet Riley Martin would know.

Hahahaha that is funny. That sound can be ENC or Digitial. I still say its Drunk Alliens to me! They are coming for us.....

 

[w4rez]

Local interference, perhaps?
I'm thinking it's *not* the CG, for if it were, I would imagine that somebody else on here would be familiar with it and be able to identify it.

 

[Joseph11]

I'm pretty sure that's rolling code voice inversion.

 

[csvff78]

Its not rolling code voice inversion. Rolling code voice inversion sounds identical to regular voice inversion. The NFL uses that for the QB helmets and it certainly does not sound that odd. I have never heard anything like that around here. Sounds like out of tune AM with interference. I have no idea what it is.

Looks like you've stumped the band.

Frank K3FSS

 

[mkewman]

I bet Riley Martin would know.

don't you know? thats the voice of oqatangen wan. aka tan.

hehehe

 

[AuntEnvy]

Is that how it's spelled?

 

[JoeyC]

Its some type of interference.

 

[policeMonitor]

you can hear it on channel 19 on the cb from time to time its called whitenoise

 

[N4DXX]

That noise is p25 turned inside out,upside down,front to back voice inversion encryption decoded spiraling packet fed thru a linksys roughter at 54mb per 3 hour shift. with the north and south pole phased out .I looked it up on google