Re: Standard Valve PA Stages

On 23 Jun, 16:11, "John" <m...@xxxxxxxxxxx> wrote:
"Nick B." wrote in message

I'm told that someone was asking for a reference to a standard valve
PA design.
There was a time when one had to be able to draw the circuit diagram
for one, from memory, in order to pass the _REAL_ RAE.

73 de G3NYY

What, with no 'prior authority' for the design ;-)

It's certainly in my 1971 copy of Radio Amateurs Examination Revision
Notes (G L Benbow G3HB). I'll reproduce the appropriate section here just
in case anybody wants to print it out and stick it to the top of their
FT-101E :^)

"Transmitter tuning:

Implies resonating all tuned circuits at required frequency. Tune anode
circuits to minimum anode current or maximum grid current of following
stage. PA tuning requires connection of dummy load (70 ohms). Adjust
tuning capacitor to minimum anode currentwith loading capacitor at
maximum. Decrease loading capacitor until PA is drawing anode current to
give input power desired (probably necessary to readjust slightly the
tuning capacitor)."

The accompanying circuit showing an 807 with 375V HT on the anode and a
pi-tank output circuit.

Thats no good. The FT101E didn't use 807s.- Hide quoted text -

- Show quoted text -

.... but 6146s are beam tetrodes, just like 807s.

Easy peasy lemon squeezy - we had 12 year olds tuning up my FT901DM on
last year's JOTA. Can't see why a grown man and experienced "ham"
would struggle with it.

73
Mike G4KFK/A6 (it ain't 'arf 'ot Mum)

.

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