You're quite right. I thought about this, but made the suggestion that I did because it worked for me. These circuits are very non-critical, and if you can adjust the inductance and one capacitor it
If I remember my theory correctly, varying any of the pi network elements changes both the center freq and impedance match. You must have at least two elements variable to change CF and match indepen
There is some available inductance variation by squeezing/separating the turns on thre toroid. As I said, I had good luck making the input capacitor variable and the output fixed, but one could certa
The Sb200 has fixed caps on input and output and a slug tuned coil. Tuning the coil moves the center frequency while the swr remains relatively constant. 73 Gary K4FMX ______________________________
Instead of designing and testing multiple pi networks then working out the switching with the plate tank, why not use a simple multi frequency tuner. One variable cap and one coil, you can peak the d
Carl, Use a dual 350/400 ufd cap out of an old tube type bc set. Coil should be 1 and 1/2 to 2 inches in dia approx 60 turns. Center tap the coil. Connect one side of the coil to one stator on the ca
This could be another way to achieve continuos tuning input: http://www.wb8erj.com/813mainsch.htm Best regards Guillermo - LU8EYW. Bob Kirkland escribió: ______________________________________
Carl, It is an old,old circuit. It was in QST many years ago. It was designed to be a plate tank for a low power class c amplifier. Just how to couple in and out of it I don't remember, but I do know
Hola Guillermo, Yes I agree that input circuit works well however it would be a little awkward in a multi band amp in changing frequencies. I like the swamping resistor across the coil. Bob,w5pvr ___