Hi group.
I'm Thomas, La3PNA and I'm in the progress of starting to build an HF
amplifier with 4 811A tubes. I'm gone to use 4 of them because, I got
the tubes, sockets and Plate caps for 4. I have drawn an shematic that
can be found in the folder "LA3PNA 811 amplifier" in the Files section.
I have drawn it as an one band unit, mostly since the rotary switches
in Eagle are stupid drawn, I would like to make it work at all nine
HF bands, from 160M to 10M.
I wrote an e-mail to R L MEASURES and got an nice answer on some of my
questions. He recomended to use 5 of 811, but i think that it is a bit
hard to get 5 matched tubes?
I have found out that one 811 tube has an impedance of 300 ohm's so 4
of them should give an inpedance of 75 ohms. Is this correct? found
the data in an old ARRL handbook, on an article on an one tube amp.
Hope that some of you have time to take an look at my design and
please let me know if there is any errors.
73 de Thomas LA3PNA
PS: sorry for my bad English.
