Ben: Welcome to the world of SWL'ing in the new Century...

It sometimes seems the whole world is a huge RF noise generator, and
the more urban your listening location, the worse off you're likely to
be. Too, just wait 'till 'BPL' (broadband over power lines) becomes a
reality...

Known RF noise generators commonly found in the home:

Light Dimmers
Computers
Televisions
Fish Tank Heaters
Electric Blankets
Microwave Ovens
Cell phones

And if you're in a suburban neighborhood, these noise sources can be
coming from any (or all) of your neighbors homes.

If you're attempting to hear the microwatt station from Micronesia,
you'll need a well considered antenna system to improve the signal
(good) - to - noise (bad) ratio.

Generally this means an antenna that is erected as high as possible,
and at right angles to known noise sources.

An antenna tuner attempts to 'transform' the impedance of a random
length wire to 50 ohms; useful in *transmitting* applications, but of
little or no use in reducing electrical noise interference to a
receiver.

A better bet would be a device that captures the same noise as your
main receive antenna, then 'compares' this common noise signal and
cancels it out. Search for the 'Timewave ANC-4 RF Filter', a somewhat
fussy, but very effective "locally generated noise eliminator".

Good Luck.

MW