>Hello,
> Can someone tell me the difference between the 77d, 77dx and the 77sx
D = one tube. S = 2 tubes.
- The tank in the 77 is designed for a 2000 ohm input and 50 ohm output.
Two 8877s have an anode output Z of roughly 1000 ohms.
- If one were to re-design the 77's tank for 1000 ohms (with a Q of 10
to 15), fix the existing load C padder problem on 160m, and install a
more capable hv transformer--provided that one had the needed 160w of
drive--the bottom-line would be about 2/5 of one S-unit more signal at
the receive end.
- IMO, a better approach would be a single 8171, Class AB1 grid-driven.
The bottom-line would be about 1-1/3 S-unit more signal at the receive
end--and having done a fun, educational project.
- However, I do not believe in using more power than is necessary to
communicate.
cheers, Ron
Rich---
R. L. Measures, 805-386-3734, AG6K
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