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.

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

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
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