01-09-2021, 08:57 PM
Hi.
On my 1J42A pantry transmitter if I varied the control grid voltage of the one that wasn't used for the oscillator feedback, the result was the resultant output varied as per the DC applied. This is logical as I used this grid for the AF input. The 1j37b of course is bi control grid as well. I'd say that using these Bi grid valves that AGC could be applied to one grid.
One project I started was using a 1J42A as a frequency changer, my issue was the lack of coils etc but I did use one grid for local osc and the other for RF input, there was a resultant IF at the anode. It wasn't very good and I got fed up with it and abandoned the whole thing. I'd say the 1j37b would be a better proposition though. May go back to it one day using the higher voltage valves.
On my 1J42A pantry transmitter if I varied the control grid voltage of the one that wasn't used for the oscillator feedback, the result was the resultant output varied as per the DC applied. This is logical as I used this grid for the AF input. The 1j37b of course is bi control grid as well. I'd say that using these Bi grid valves that AGC could be applied to one grid.
One project I started was using a 1J42A as a frequency changer, my issue was the lack of coils etc but I did use one grid for local osc and the other for RF input, there was a resultant IF at the anode. It wasn't very good and I got fed up with it and abandoned the whole thing. I'd say the 1j37b would be a better proposition though. May go back to it one day using the higher voltage valves.
