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Old 20th Aug 2019, 11:53 am   #16
Hybrid tellies
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Join Date: Jan 2004
Location: Bristol, UK
Posts: 2,456
Default Re: Spitfire AM Transmitter Hum (Buzz)

When I first built and installed my SSTRAN it worked perfectly but the levels of hum and noise just got worse making it totally unusable.
I also find the same levels of hum and interference on the stronger broadcast stations such as BBC R5L and BBC R Wales.
I thinks its a kind of modulation hum from cheap and nasty SWPS's, cheap and nasty LED and CFL lamps and ageing poorly designed Plasma TV's all radiating back along the mains wiring affecting all or many surrounding houses. It a problem that has been allowed to get totally out of hand.

The interference levels on mains operated radios is very bad, not quite so bad on portable radios running on batteries. I find that the levels of noise and interference can be reduced to not so annoying levels by moving a portable radio running on batteries to different parts of the room.

Going back to the pantry transmitter problem I hope to start experimenting with the earth, it looks like a direct earth connection to the pipe work or mains earth is a bad idea. Using a counterpoise earth, leaving the earth wire of the Spitfire or SSTRAN just trailing across the room not connected, say around the skirting board, this slightly reduces there range but does seem reduce the hum and buzz interference by a useful amount.
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