[FedCom] FBI Radio Systems Keyups?

[Tom Greenwood]

Has anybody made any attempts at looking at the transmissions using an audio
spectrum analyzer such as the program Spectrogram to see if there are any
subaudible data transmissions?  I have used this program in the past looking
at data transmissions with very interesting results.  As I recall, the old
414/419 links were rather revealing once looked at this way.

73's
Tom, N1JQB
Metro West Boston


-----Original Message-----
From: fedcom-bounces at mailman.qth.net
[mailto:fedcom-bounces at mailman.qth.net]On Behalf Of Ken
Sent: Saturday, March 22, 2008 10:15
To: Discussion of Federal Government Communications
Subject: [FedCom] FBI Radio Systems Keyups?


I've noted for many months now that in my area 167.5875 (CTCSS 167.9), keys
up once every 40 seconds or so, with a dead carrier for about 1 to 2
seconds.

Is there a reason now for these keyups?  (e.g. does it display radios
numbers in range and/or indicate to units that they are within range of that
specific site?).

Ken
Springfield MA Monitoring Area


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