12-06-2022, 05:42 PM
All these Gilbert Davy's Radios will work with rod tubes:
http://www.daveysradios.org.uk/index.html
I have the 2nd edition of his book somewhere.
Many designs to download.
Obviously the mains ones may need adapted and HT for g2 should be via an HT tap or voltage divider if a lower than HT volts needed for g2, though will work with a single resistor. AGC to g1 won't work because sharp cutoff. Either use a 1 M pot with 2 resistors to give 15V to 60V on g2 for RF gain (or IF gain) or use the anode of a DM70/DM71 magic eye as AGC amp to drive g2.
Replace heptodes and octodes with two rod tubes, they'll work in the existing circuits with one tube as osc triode with its anode driving RF input pentode g2 direct. Signal to g1. I've replaced DK91, DK92, 1L6, DK96 with pair of 1j24b. A triode-hexode ECH81 / UCH81 etc can be replaced with same pair of devices and wiring as the DK92 replacement.
The Rod tubes have a similar upper frequency limit to an EF80 so will work at VHF.
http://www.daveysradios.org.uk/index.html
I have the 2nd edition of his book somewhere.
Many designs to download.
Obviously the mains ones may need adapted and HT for g2 should be via an HT tap or voltage divider if a lower than HT volts needed for g2, though will work with a single resistor. AGC to g1 won't work because sharp cutoff. Either use a 1 M pot with 2 resistors to give 15V to 60V on g2 for RF gain (or IF gain) or use the anode of a DM70/DM71 magic eye as AGC amp to drive g2.
Replace heptodes and octodes with two rod tubes, they'll work in the existing circuits with one tube as osc triode with its anode driving RF input pentode g2 direct. Signal to g1. I've replaced DK91, DK92, 1L6, DK96 with pair of 1j24b. A triode-hexode ECH81 / UCH81 etc can be replaced with same pair of devices and wiring as the DK92 replacement.
The Rod tubes have a similar upper frequency limit to an EF80 so will work at VHF.
