Hi Jack,

See if you can find a project called "A 75 to 120 Watt CW transmitter"
in any of your ARRL manuals, (1973 ?).

Z1 is the APC, RFC4 is the anode RFC, there is a 10R grid stopper on
G1 (pin 5), Decoupling abounds (including the heaters), band switch
shorts unused turns of the output inductor, top chassis shows anode
wiring only, bottom chassis shows grid and drive electronics.

I haven't read the whole article yet, but it seems like a well
designed beastie and a good starting point.

Keep a change of fresh underwear next to the rubber gloves

Regards,

Mark


On May 24, 12:26 pm, Jack Schmidling wrote:
MarkAren wrote:
Grid stoppers: A low value resistor (100 ohms) attached directly
between G2 and the screen supply to reduce the incidental Q of
circuit.

OK but the supply is a 12K resistor from the plate supply. Guess I
don't see what a 100 in series with this would do.

Same applies to G1.

Where does that go? There is a 47K grid leak going through the meter to
ground and a coupling cap from the driver.

So what is this grid stopper supposed to do?

APC - Anti Parasitic Choke.

Roger. The A caused a brain cramp. I have one in there.

Get a 1960s copy of the ARRL handbook and read up on HF amplifier
construction techniques. There has been plenty written.

I have 49, 57, 61 and 73 one of which I take to bed with me every night.

js

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