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Wolf DL4YLF,
OK on receiving 50 Hz hum modulation from TV
sets.
>I guess most of the QRM travels over the mains
supply lines. I already
>considered building a battery-powered remove RX
with a 70cm-FM-link to the
>main station (using a cheap 70cm-LPD handy).
The problem is finding a quiet
>remote RX side where the RX cannot be
vandalized or stolen.
Several ZL amateurs, including myself, have had
quite good results in minimising LF QRM by using an active whip antenna sited
somewhat away from houses (and their mains wiring). Attention needs to be
paid to RF isolation of the power supply for the antenna, and using balance RF
transmission lines, otherwise the mains QRM can still get to the antenna via the
shack and feeder. 5 metres or so separation of an active whip from house
wiring can greatly reduce the mains-conducted QRM, but is still good for
receiving wanted DX signals.
73, Bob ZL2CA
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