Uwe wrote in message ...
With the help of some folks here I did troubleshoot my AC-1 tube transmitter
(using a 6V6) and got it working somehow. Since I passed my code test and
had my first QSO using the transmitter and boy was that exciting.

But questions remain.

I monitor the output signal on my scope and notice that right after key down
the waveform contract just a bit and the tone changes pitch. I guess this is
called chirp. I normally use B+ 200V.
If I increase the voltage lets say to 300V this effect becomes much more
pronounced.
I still use an external bench supply capable of much higher currents and I
don't think it is a power supply weakness. In fact putting a VOM on the
supply line shows no sag in my supply voltage.

How can I minimize this and especially keep it from becoming more severe at
higher outputs.


Also, the circuit diagram for the tranmitter did not state the coil diameter
of the pi network. The pi network still has me scratching my head. Coils
with slight variations in diameter give dramatically different results.

Also changing the air cap with one of an identical range can have a vast
effect, which surprised me. Is this the "real world components" versus the
theory???

Uwe

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Congratulations!

I still have my original Ameco AC-1 15-Watt CW transmitter, completely
intact with all original parts and accessories, all in perfect
like-new condition, and a copy of the whole manual. If you want me to
look at or measure anything for you (e.g. the coil you mentioned?),
just let me know. I am at tomg AT fullnet.com .

By the way, I think that I paid $14.98 for the Ameco AC-1 kit, new,
back in about 1969. I built it, tested it, and then never used it. And
I HAVE had people offer me hundreds of dollars for it, "out of the
blue", several times over the last few years. There's a picture of it
on my webpage (see URL, below).

Good luck!

Regards,

Tom Gootee

http://www.fullnet.com/u/tomg

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