wrote in message
oups.com...
I'm going on a service call next week to address an issue of AM radio
interference on a telephone line. The lady has her computer connected
to this line and it seems to keep getting bumped off especially
throughout the day. There is a 5KW AM transmitter operating on 610KHZ
about a quarter of a mile from the customers home.

Pick up a handful of inline filters at R shack. Add one at the service
demarc for each branch and one at each device. Inspect the ground at the
demarc (if any). Place a filter on each unused telephone jack.

Pick up some RFI filters that plug into wall outlets. Place one on each
telephone device that uses external power.
Be sure to put on the modem. Get a ferrite RFI suppressor and clamp it to
the power lead of the modem. Place it as close to the electronics as you can
get.

If the house telephone wiring is not twisted pair go ahead and replace it.
(all of it, not just the run to the computer).

If the transmitter is a directional array (2 or more towers) the stations
engineer will have a field strength meter. The RF field can be measured at
that location. You may be dealing with 2000 mV of RF or more.

I once had a guy who run unshielded speaker wire throughout his house. A
switch selected pairs of speakers in various rooms. the field was so strong
that music came out his speakers even when the stereo was turned off and
unplugged. a pair of low pass "L" filters at the amplifier took care of the
problem.