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Old 19th Aug 2019, 8:23 pm   #8
Ambientnoise
Heptode
 
Join Date: Feb 2006
Location: Marlborough, Wiltshire, UK.
Posts: 591
Default Re: Spitfire Am Transmitter Hum (Buzz)

This problem can arise when the transmitted signal is picked up by the house mains cables and then re-radiated with modulation from the mains. It can be very difficult to cure. Try to prevent the rf getting into the mains via the psu by all possible methods, incl ferrite, caps , earthing etc. The rf from the tx antenna is more difficult as the house wiring is all around ! Try putting the tx antenna in various places, in my home the landing gives the best results as the stairwell is free of mains. Use a modern battery powered radio to experiment with the tx side. Similarly, position the rx antenna as best you can. Good luck !

Ken
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