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THE AM BULLETIN BOARD => Technical Forum => Topic started by: N4LTA on June 22, 2020, 12:03:12 PM



Title: Questions on Triode 3C24 plate modulated transmitter
Post by: N4LTA on June 22, 2020, 12:03:12 PM
I am planning either a single or parallel 3C24 plate modulated transmitter running between 800 and 1000 volts.

I know it will have to be neutralized and I can't find much data for a pi net output with neutralization.

Any typical circuits out there?

Thanks

Pat
N4LTA


Title: Re: Questions on Triode 3C24 plate modulated transmitter
Post by: WD8BIL on June 22, 2020, 12:10:39 PM
Checkout the neutralization setup on Tom's 813 pi-network output rig. The pickup plate is top left of the left side 813.

http://amwindow.org/tech/htm/813/813.htm (http://amwindow.org/tech/htm/813/813.htm)


Title: Re: Questions on Triode 3C24 plate modulated transmitter
Post by: N4LTA on June 22, 2020, 08:06:37 PM
Thanks

It looks like it will take close to 6 watts to drive two tubes. I am thinking a crystal oscillator/VFO buffer and then a 5763 driver. Looking for a typical circuit for a driver for the two 3C24s.

Pi net or inductive coupling? I assume it will have to be tuned, but untuned would be better. This will be an 80 meter only rig.

Pat
N4LTA


Title: Re: Questions on Triode 3C24 plate modulated transmitter
Post by: KC4VWU on June 23, 2020, 09:49:47 AM
5763 osc/buffer, 5763 amp, 3c24 PA. If only for 80/75 tuned coupling would be better to reduce harmonic content?


Title: Re: Questions on Triode 3C24 plate modulated transmitter
Post by: WD5JKO on June 23, 2020, 12:26:16 PM


Pat,

    Take a look at this transmitter built by WZ5Q:

https://forums.qrz.com/index.php?threads/the-evolution-of-a-lonely-af-67.571414/

Might consider beefing up the driver to a 2E26.

I attach Mike's schematic here.

Jim
Wd5JKO
AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands