[Antennas] Off Topic: RFI - AM Broadcast

[Jesper Wolf Jespersen]

Hey Tim.
Sory I cut in your message.

> Starting early Friday morning I started having trouble connecting to the
> internet.
-- cut
> It was the local AM broadcast station, their tower is
> about 500 yards north of me and it was their signal I was receiving
through
> my modem.

Why dont you try winding the phone line going to the modem arround a ferrite
rod or a ferrite toroid. That will probably remove the common mode RF that
is interfering with the modem.

If that does not help then maybe you have a phone set behind the modem, the
RF may be picked up by that line as well so try putting some ferrite here as
well.

Also it may help to move the input and output lines from the modem in the
same direction so they dont work as the two sides of a dipole :-)


> My query in reference to all of this is what could possibly have changed
> that would allow such a drastic amount of interference in my modem and
what
> would you guys suggest as a possible solution?

Who knows, you may have moved the cable going to of from the modem, making
it pick up more of the RF, somebody may have put up a steel roofed barn near
you changing the local RF pattern, etc, etc.

> I am sure I will not be able to send this message until dusk when the
> station reduces power to 5KW so in the mean time with no plans of visitors
I
> am going to try additional grounding and maybe some of the chokes I have
> taken from other items before I trashed them.

In hope you had luck with your chokes, its nearly certainly common mode RF
being detected by the modem and what you need to to is dampen this.
It must come in via a cable since the wavelength is to long for the signals
to couple directly to the cirquitry in the modem.

Hope you solve your problem.

Greetings from Denmark
Jesper Wolf Jespersen