[Amps] Building an Amp 101

[peter chadwick]

After doing some simple calculations, I think you only need 6 positions on the tank switch. 160, 80, 40, 30/20, 17/15, 12/10. The Acom 1500 uses 7 positions as 160, 80, 40/30, 20, 17/15, 12/10, 6. But leave out 6 and the difference is between using 40/30 or 30/20.

The problem comes with switching input circuits in GG, but if you motorise the PA bandswitch, that's no real problem. The ex TU unit switches (TUs for the BC191) are cheap ($5.95) from Fair Radio Sales (catalogue 3Z9605) and with some cunning, they can be ganged - there was a 'how to' article many years ago in CQ. A big Ledex or a stepper motor could do it. I don't know their rating but it has to be big. However, they are not progressively shorting, but you could still short out the bit of coil you're not using.

I ought to go out to the workshop and see what volts they flash over at....

73

Peter G3RZP