[MilCom] Southern MD Audio Log Notes (05/15/04)

[lrk]

On Sat, May 15, 2004 at 09:04:30AM -0400, Jeff wrote:
> 
> 138.875
> Well, I am tired of messing with this one. I must have had over an hours
> worth of recorded audio from a Cell Site Sub-Harmonic. Seems to be this new
> SINGULAR Cell Phone net as a few times people Dialed information and the
> Operator stated Singular. They must have put some antennas up on one of the
> towers nearby.

This is a common problem with the PRO-20## series radios, maybe others.
It is due to the various frequencies involved in the radio. Recent scanners
are supposed to be less of a problem to reduce ways of monitoring cell
phones.

These plastic radios can receive right thru the case so some freqs get
thru even with filters on the co-ax. The only way to fix this is thru
experimentation to determine how it happens.

If it is coming in on the co-ax connector, a low-pass filter for about
400 MHz would work. If it leaks in thru the case, wrapping it in aluminum
foil might work.

But it is probably your scanner, not the cell site that is at fault.


For you techies out there:   (139 + 610) * 2) - 610 = 888 Mhz


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