"mike" wrote in message
...
yep sounds like very close bleedover to me.
have a scan of the portable phone freqs (lists r on the web)
probably a wander phone of a neighbour.

Undoubtedly, it's pagers- digital and voice in the 152-153 and 158 MH
spectrum causing intermod.

do this on the duck, then u should find it.
then it's time to make a coax stub filter
very easy, plans r on the net also
Unfortunately a coaxial stub filter has 2 serious drawbacks:
1. Notch depth is limited to about -20dB
2. a Stub, say tuned for 152 MHz will still have -10dB loss at 154 MHz.
u r not along on this problem.
most , bar the really expensive scanners do it.
sadly their front ends r very open.

could try changing the ceramic filter if u r that way inclined.
The ceramic filters are in the IF stage- the IM occurs in the RF stage, so
changing the ceramic filter will not help- the IM is already there.

See: http://www.grove-ent.com/filters.html
for a solution.
not too diff, but u need to know about electronics.

as an after thought.
try earthing your coax braid to a radiator or water pipe
that might help


mike
"John Ellenberger" wrote in message
...
I purchased the Radio Shack Pro-82 as my first scanner. Works
reasonably
well with the included antenna. I bought an external antenna from Radio
Shack and when I hook it up I often get noise that overrides all
channels.
The noise starts out with two very loud tones and then it sounds like a
phone conversation in the background and often the loud tones repeat.
The
seems to happen in bursts of a few minutes and basically the scanner is
useless during this activity.

My only theory is that its somebody talking on a Nextel phone(?)

Any ideas on what it is and what I can do about it?

John