BITX20 & BITX40

arvevans@...
 

Hello to the BITX20 group (this is my first posting on this forum).

Farhan and myself have exchanged a couple of off-forum emails regarding mods to his excellent design. One interesting possibility is replacement of the LM-386 with a discrete component AF Amplifier. He said that he had not had the time to work up a schematic...so I have provided one (see attached .gif file). This can allow those without access to an LM-386 to build the unit.

Also, my layout for the BITX20 uses 10.7 MHZ IF transformers salvaged from dead AM/FM radios ( I dislike winding toroids! ). My construction is a BITX40 (40 Meters) and requires 55 pf across the 10.7 IFs to resonate on 7.2 MHZ. These 10.7 IF transformers might be made to resonate on 20M if the internal capacitors were removed ( break them with a screwdriver point ) and a small variable ( 5-25pf ) used to bring them to resonance.

73's
Arv - K7HKL

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