22-03-2021, 03:26 PM
Looks a useful circuit, good work 
The 4k7 resistor in series with the oscillator feedback winding, was that arrived at empirically, and if so, how?
Operation of the mixer valve is different from the conventional DK96 changer, as it has RF applied to the first grid whereas the pentagrid puts the incoming RF on its 3rd grid. Might even be more sensitive, do you have any comparative data, such as, most distant station received for original and for Russian replacement?
Finally, did the IFT primary need any twiddle to bring on-tune with the 1j24b?
These little rod pentodes are addictive...
The 4k7 resistor in series with the oscillator feedback winding, was that arrived at empirically, and if so, how?
Operation of the mixer valve is different from the conventional DK96 changer, as it has RF applied to the first grid whereas the pentagrid puts the incoming RF on its 3rd grid. Might even be more sensitive, do you have any comparative data, such as, most distant station received for original and for Russian replacement?
Finally, did the IFT primary need any twiddle to bring on-tune with the 1j24b?
These little rod pentodes are addictive...
