On Wed, 20 Dec 2006 17:40:51 -0600 "Mike W2LO" <rfman45@hotmail.com>
writes:
>
> There are two ordinary wooden "telephone" poles in my
> neighborhood
> carrying just H/V and telephone lines-no transformers, etc.-just the
> wires
> supported by two insulators. Occasionally when I pass them while
> walking,
> there is a fairly loud hum coming from them.
It's most likely the wind, even a fairly light or "calm" wind, that
can cause the wires to vibrate at some audio frequency. Sometimes
vibration dampeners are placed on long spans to reduce/eliminate
destructive vibration. Those can be seen on HV transmission
lines and even on the guy wires of tall towers.
In your example, the vibration may ultimately loosen
connections and/or hardware and then you'll have RFI.
Charlie, N0TT
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