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Thursday, March 23, 2023

More Cuban Homebrew from the 80's and 90's -- A 160 Meter AM (Controlled Carrier) TX with Soviet 6P23s

160 Meter Transmitter

Jose CO6EC writes: 

I will be sending you some work of homebrew from the 80's and 90's when practically everything was manufactured by Cuban radio amateurs

The photos are of a Modulated Amplitude TX for the 160 Meter Band, about 25W of which several were made.  The final tube  was modulated in many cases by a 6DQ6, 2E26 or other similar ones that were very abundant at that time. 

This one in particular is  made with valves  6BH6 for the VFO, 6CL6 for the amplifier step and 6P23 Soviets in the final part, the modulator was made up of a 12Ax7 microphone preamplifier and a 6BM8 that came out through the cathode to the screen grid of the 6P23, in this way the carrier was controlled by modulation what we called  Carrier Control as there was no voltage on the grid at the ends there was practically no carrier  in the air which gave the impression of transmitting in SSB. hihihihihihi

For those who did not have a communications receiver, a conventional radio was adapted to receive that band, which in many cases was a VEF-206 of Soviet construction, to which an oscillator was adapted to beat the signal and get exactly on frequency. This was very popular here in the late 80's and early 90's. 

Thanks Jose.  We look forward to learning more about Cuban homebrew. The way in which radio amateurs got on the air with gear that they made themselves using the limited parts available to them is really interesting and admirable. 73  Bill 

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