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Title: Interesting single ended high efficiency modulator Post by: Opcom 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. Title: Re: Interesting single ended high efficiency modulator Post by: kb3ouk 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.
Title: Re: Interesting single ended high efficiency modulator Post by: Opcom on March 11, 2012, 11:37:31 PM Sorry I was being facetious about the iron. I got about 300 lbs of those transformers. AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
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. |