NotTaR of Television Sets : EM or RFI hell?                         
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EM or RFI hell?

"About a mile from my home there are four TV (channels 2, 4, 9 and 14) and several broadcast FM transmitters, all working with powers in the 100+ Kw ERP class.

Radio reception is a nightmare, mostly (I think) because of IM products in overloaded front end stages. In most bands there are several regions at a spacing of about 100 Khz, each 30 to 40 Khz wide with a harsh buzz stronger than anything else."

(From: Don Klipstein (don@Misty.com).)

If the buzz is of a frequency like the power line frequency or a harmonic thereof, then the nearby transmitters may not be the culprit. Instead, nearby corona on a high voltage power line, a nearby neon sign, or a nearby light dimmer may be the offender. Although the noise from these is usually broad-band, the noise could get concentrated into bands spaced 100 kHz apart if something resonant around 100 kHz is involved in the noise production.

I would try temporarily turning off all fluorescent lights, neon signs, lights with dimmers, etc. and asking your neighbors to do the same to see if any of these is the offender. I have often found light dimmers to be major RF noise sources.

Possibly, an RF noise filter for the AC power for your receiver may help things. If you isolate a single offending appliance, it may help to plug it into an RF noise filter. If you use any filters with either the offending appliance or the receiver, try all combinations of plug reversal to see what works best. Both leads of any offending appliance may not equally spew noise, and both lines in the filter may not equally block noise. Both lines of the receiver's power cord may not equally bring noise into the receiver, if this is the route the noise takes.

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