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OK, let's look at the low voltage supplies for the control circuits and antenna relays. I needed 28v at 700ma for relays, and 12v at <500ma for the sequencer and fans. I used a 25.2v/2A filament transformer (Radio Shack), a full-wave bridge, and an LM-317 regulator IC for the 28v, and just came from there with a simple 7812 regulator for the 12v. I mentioned my dislike for noisy fans before, so I also used a simple speed control circuit to run the computer-type muffin fan at half speed; a lot quieter, yet it moves enough air keep the entire power supply cool. |