How to eliminate FM RF coming thru turntable?


Mitchell GYRO SE turntable picking up FM RF after 5 PM to late at night. During the day, no FM RF being picked up by turntable. All other components, no RF (tuner, CD, tape). All components connected thru Furman power conditioner. Have run separate ground from Furman to turntable ground at preamp (Rogue 99) which reduces the FM RF considerably, but does not eliminate. FM interference reacts to volume control. FM RF disappears when turntable leads disconnected. Any suggestions?
128x128fossilsx15
Almarg...A corrosion-formed diode can indeed rectify an AM station's signal so as to produce recognizable audio. In my experience what you usually get is a mixture of several stations, some louder than others.

However, it takes a lot more than a diode to pick up recognizable audio from a FM signal.
A corrosion-formed diode can indeed rectify an AM station's signal so as to produce recognizable audio. In my experience what you usually get is a mixture of several stations, some louder than others.

However, it takes a lot more than a diode to pick up recognizable audio from a FM signal.

Hmm, yes, you have a good point there.

But still, if we understand the facts correctly (recognizable audio from fm, being introduced through the phono input, and present (I assume) when the fm tuner is turned off), SOMETHING in the phono path is somehow demodulating the signal. Not sure what that could be.

Regards,
-- Al

Thanks for the suggestions -- will give them a try. Just completed a year long renovation. The equipment was originally in the center of the house and rarely if ever had an RF problem. Now, equipment is housed in a wood cabinet against an exterior wall. A new FM antenna is about 10' from the turntable on the eaves. Disconnected the cable to the antenna and still have RF signal. The same station comes in when the night signal changes. It makes no difference whether the tuner is on or off with the RF. Again, during the day, phono is dead-quiet.
This is just a wild guess, but since it's only happening at night, could it somehow be related to the fact that lights are on (vs. during daytime)? I'm no electrician, but it seems that the difference between night and day might be the clue here. I wonder if the house wiring is somehow acting as an antenna/repeater (from the renovation you mention) is causing the issue, but only when the circuit is closed such as when lights are on.

Again, a wild-assed guess at best but logic dictates ruling it out as a cause.
Are you using a tube or solid state phono stage?

I had similar problem and after trying many great tube phono stages, eliminated the trouble only by switching to ss phono stage. Cheers,
Spencer