10-05-2016, 04:58 PM
Hey Eric,
Methinks your vc circuit should be closer to this:
http://www.nostalgiaair.org/pagesbymodel...008952.pdf
A lot of the old TRF sets the vc on one end is tied the ant and the other the the cathode circuit of the rf amps, wiper is grounded.
How it works is as you turn the vc down it lessens to resistance from the ant to the chassis esscenually shorting the ant to ground. And at the same time it's also increasing the resistance of the rf amps cathodes to ground raising the cathode voltage higher which lowers the gain.
Conversely turning the vc up allows more signal to pass though the vc from the antenna and brings the cathodes in the rf amps closer to ground which increases the rf gain.
Repeat after me, no IF no IF no local oscillator no local oscillator.
GL my friend
Methinks your vc circuit should be closer to this:
http://www.nostalgiaair.org/pagesbymodel...008952.pdf
A lot of the old TRF sets the vc on one end is tied the ant and the other the the cathode circuit of the rf amps, wiper is grounded.
How it works is as you turn the vc down it lessens to resistance from the ant to the chassis esscenually shorting the ant to ground. And at the same time it's also increasing the resistance of the rf amps cathodes to ground raising the cathode voltage higher which lowers the gain.
Conversely turning the vc up allows more signal to pass though the vc from the antenna and brings the cathodes in the rf amps closer to ground which increases the rf gain.
Repeat after me, no IF no IF no local oscillator no local oscillator.
GL my friend
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
