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Author Topic: Interesting single ended high efficiency modulator  (Read 2112 times)
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Patrick J. / KD5OEI
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« on: March 11, 2012, 03:31:23 PM »

RCA Ham Tips, summer 1964

one large tube, one small one, a TV set power transformer. Can modulate 6146-type 'novice' transmitters like the Apache, and makes >100% positive, 95% negative modulation. It uses a 6JE6 but any tube able to pass high currents at low voltages can be used. The beauty of this is the way the transformer is used to aim for a balanced DC situation with a step-up of voltage. I can't imagine where to get TV power transformers any more tho/. have not seen one in years..

An interesting feature of the design is the way the negative side is limited is combined with a clamp which is kind of soft.

* RCA_HAM_TIPS_24-3.pdf (307.1 KB - downloaded 179 times.)

* single ended mod.gif (101.45 KB, 1017x945 - viewed 482 times.)
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« Reply #1 on: March 11, 2012, 04:24:07 PM »

what says it has to be a TV power transformer? any 600-900 volt or so power transformer should work, just tie one lead of the primary to one lead of the secondary and you're good to go.
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« Reply #2 on: March 11, 2012, 11:37:31 PM »

Sorry I was being facetious about the iron. I got about 300 lbs of those transformers.

I really like the 'pull-push' arrangement. OK it's a half wave voice, almost, but his waveform looks good and it is a lot less complex than other supermod schemes.
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