Never heard before

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ampulman

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While monitoring Federal frequencies this morning, I heard on a frequency listed as FBI, a series (about 10) rapid-fire beeps, followed by squelch. The pattern was repeated at various intervals. It appears to be an analog signal.

At first I thought it was an alert tone, but waiting for audio proved negative.

Anyone familiar with this?

Amp
 

signal500

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While monitoring Federal frequencies this morning, I heard on a frequency listed as FBI, a series (about 10) rapid-fire beeps, followed by squelch. The pattern was repeated at various intervals. It appears to be an analog signal.

At first I thought it was an alert tone, but waiting for audio proved negative.

Anyone familiar with this?

Amp
DTMF auto-dial memories that can have up to 16 digits programmed into the radio used to indentify a unit or to access a closed repeater. The "squelch" is encryption.
 

ClayD

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While monitoring Federal frequencies this morning, I heard on a frequency listed as FBI, a series (about 10) rapid-fire beeps, followed by squelch. The pattern was repeated at various intervals. It appears to be an analog signal.
What frequency did you hear this on in south jersey?
 

ampulman

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DTMF auto-dial memories that can have up to 16 digits programmed into the radio used to indentify a unit or to access a closed repeater. The "squelch" is encryption.
would it matter if all of the tones were the same?

Regarding the "squelch", at other times, there would be a repeating series of hiss-squelch, hiss-squelch, hiss-squelch. Again, appears to be analog.

Amp
 

ampulman

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What frequency did you hear this on in south jersey?
I had to monitor again, as I didn't note exact frequency (had several in same range). It's 173.9375.

The frequency has been in my scanner for some time; only started the beeping at the time of first posting.

Amp
 

nd5y

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While monitoring Federal frequencies this morning, I heard on a frequency listed as FBI, a series (about 10) rapid-fire beeps, followed by squelch. The pattern was repeated at various intervals. It appears to be an analog signal.

At first I thought it was an alert tone, but waiting for audio proved negative.

Anyone familiar with this?

Amp
I have heard that on either the FBI or DEA (or both, I can't remember) in the Dallas/Fort Worth area. It might be some kind of telemetry or alarm or something. It isn't DTMF.
 

signal500

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would it matter if all of the tones were the same?

Regarding the "squelch", at other times, there would be a repeating series of hiss-squelch, hiss-squelch, hiss-squelch. Again, appears to be analog.

Amp
Tom could be correct, it might be an alert tone indicating that a door was opened at the repeater site. Of all of the federal sites I have worked at over the years, the building alarm would just call a preprogrammed number (such as a cell phone) to notify of an intrusion.
 

Squad10

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would it matter if all of the tones were the same?

Regarding the "squelch", at other times, there would be a repeating series of hiss-squelch, hiss-squelch, hiss-squelch. Again, appears to be analog.

Amp

The hiss is most likely 1200 bps DPSK modulation sent from a Motorola MOSCAD SCADA Remote Terminal Unit. It usually occurs after a series of single tone beeps.
 

nd5y

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The hiss is most likely 1200 bps DPSK modulation sent from a Motorola MOSCAD SCADA Remote Terminal Unit. It usually occurs after a series of single tone beeps.
What I used to hear was only beeps and a squelch tail because the radios making the beeps didn't have reverse burst. There wasn't any data. I'm not saying that's not what the OP is hearing at his location.
 

kennyloatman

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I had to monitor again, as I didn't note exact frequency (had several in same range). It's 173.9375.

The frequency has been in my scanner for some time; only started the beeping at the time of first posting.

Amp
I am hearing it tonight too, seems to be at five minute intervals 10 to 12 beep burst. very loud and clear.
 

Armadillo5

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While in St Louis a few years ago I heard these same beeps/tones keying up repeater's in that area. The next day while in Oklahoma I heard the same beeps/tones keying up repeater's in that state. Then, the next day after that while in Texas I heard the same beeps/tones keying up repeater's in that state.

All connected, all with the same beep's/tones, ALL happening right about the same time of day. At the end of each beep/tone, there was a loud burst kinda like DES but it was not DES. Sounded more like a break in squelch but DEFINATELY not any form of encryption.

Also, recently while in the mid-west I heard on 167.7125/analog, P-25 ENC trying to pass through that repeater. The signal was fairly strong and you could hear the P-25 trying to pass through but completely un-readable due to both being different forms of technology. Then after that a unit tried calling on the analog side but the response was trying P-25 ENC.

This was just an experience about 2 yrs ago. Now, I just hear the repeater keying up but no beeps/tones or loud burst.

I am no expert but this is my two-cents and maybe it helps. Happy Scanning!
 

Squad10

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Maybe somebody could post audio sample(s) of what they are hearing.

In one post it sounds like the MDC1200 packets preceed a SecureNet encrypted transmission. If this is the case a short high pitched (End Of Message) tone should be heard at the end of the encrypted transmission. This type of system was used 10+ years ago by Chicago INS.

The second description as I understand it is a series of single tone beeps followed by a low modulation deviation 2-3 seconds fax-like sound.

Am I understanding correctly?
 

Armadillo5

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I have no way of posting the audio but your right in the ballpark for what it sounds like. It was as if some data was trying to push through but then dropped out. Kinda like packet or the old modems we use to use on our computers back in the early 90's.

I did a test from one state to another and it was the same each time I traveled through. Some states had it more than the other and it was happening in states in the southwest to midwest. There was a channel in the 163.???? range along 75 up through Oklahoma that would pop up. Then when you get over to St Louis it would pop up again. Jump down to DFW and you would hear the same thing.

By the way it was not OTAR either.

One other note, I remember 2 yrs ago folks around PA were hearing the same thing. If you read back over the forum from then people were writing in about it.
 

gewecke

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In past years in norther ill. I have heard the same thing,only a series of 4-5 single tones simulcasted on 167.2375mhz./167.9pl and 414.575mhz./167.9pl It was explained to me that this was a polling system to check operation on various link tower sites which were connected between Ill. and wisconsin.
Although I haven't heard them as of late.
n9zas
 

Squad10

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In past years in norther ill. I have heard the same thing,only a series of 4-5 single tones simulcasted on 167.2375mhz./167.9pl and 414.575mhz./167.9pl It was explained to me that this was a polling system to check operation on various link tower sites which were connected between Ill. and wisconsin.
Although I haven't heard them as of late.
n9zas
The 408/414/419 mHz Chicago FBI link frequencies have not been used for many years. They were replaced by 1714/1812 and 1746/1842 mHz. Link frequencies are used to extend voice communications coverage areas for the Chicago Field Office and Resident Agencies VHF HI communications systems and carry other non-voice information.

Occasionally, the series of single tone beeps and low level fax-like sounding data will be heard on FBI and DEA fixed station frequencies in the Chicagoland area.
 

Audiodave1

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I heard this on the channel on the way home today (FBI A-6 R-out) and it just sounded like a tone to me on the 396.

Monitoring now....It is just a series of tones and a slightly dirty un-key. Maybe indicates trouble at the TX site?

Dave
 

Audiodave1

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Us locals have determined it is VERY LIKELY a trouble alarm. Likely the site had disconnected from the network. (phone / T1 or what ever interconnect to the main office) We also noted no fed activity on it since this condition started.

I believe it had been fixed as of today.

Dave
 
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