Wednesday, April 4, 2018

Rebuilding The Heathit AT-1 Transmitter - Winding Inductors

As mentioned earlier, I will reuse the original band switch and oscillator coils, power transformer and filter choke. I decided to wind new RF chokes using toroidal cores.

It calls for two 1.1 mH chokes and one 90 uH. I used a little toroid design application I wrote myself and came up with these designs:

   1.1 mH: FT-82-43 core, 44 turns, #28 wire.
     90 uH: FT-50-43 core, 13 turns, #28 wire.

I wound them and measured the values using my AADE L/C meter. They read a little low so I added a few turns.

One other part I didn't mention earlier - I will replace the line cord with a new one using a brown two-wire extension cord that is similar to the original.

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