John, N9JG wrote:
Finally, I
found that the only way to prevent feedback on SSB was to NOT connect my
system to the #8 ground wire that runs out the window sill and down to a
ground rod.

Yep, everyone should realize that a ground wire is N*1/4 wavelength
at certain frequencies, and at those frequencies, is an RF transformer
that locates the standing-wave voltage maximum points at the transmitter. (ouch!)
That's what artificial grounds do - change that *electrical* length
to N*1/2 wavelength. For anyone insisting on an RF ground for an upper
floor, an artificial ground is probably the way to go. I, myself, prefer
balanced antennas and feedlines.
--
73, Cecil http://www.qsl.net/w5dxp