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Title: 5 Watts with one tube Post by: WA4WAX on December 30, 2018, 02:51:16 PM Oscillator-amp.
Could be modulated. Have fun! https://www.americanradiohistory.com/Archive-Radio-TV-Experimenter/Radio-TV-Experimenter-1965-04-05.pdf Title: Re: 5 Watts with one tube Post by: W8ACR on December 30, 2018, 04:40:09 PM Very similar to the 6T9 transmitter seen in some ARRL publications in the 1970s. I have built one and get it on the air periodically. Nice little cw transmitter. What would you modulate it with? A single 12AU7? PP 6AQ5s? Maybe screen or grid modulation would be better.
Title: Re: 5 Watts with one tube Post by: K2FW on December 30, 2018, 06:31:54 PM A wonderful archive of Radio Magazines in PDF Format.
TKS! Title: Re: 5 Watts with one tube Post by: WA4WAX on December 30, 2018, 08:40:21 PM Maybe an LM380N and a backwards audio transformer.
No tube.....that may upset some. Title: Re: 5 Watts with one tube Post by: KD6VXI on January 01, 2019, 11:46:32 AM I'm thinking push pull 4-65s.
Headroom, ya know? 😂🤔👌 --Shane KD6VXI Title: Re: 5 Watts with one tube Post by: WD5JKO on January 02, 2019, 07:20:45 PM Very similar to the 6T9 transmitter seen in some ARRL publications in the 1970s. I have built one and get it on the air periodically. Nice little cw transmitter. What would you modulate it with? A single 12AU7? PP 6AQ5s? Maybe screen or grid modulation would be better. As a Johnny Novice back in 1972, I built one of these on an Olsen Electronics radio chassis. Instead of a Compactron 6T9, I used a 6AW8 from an old TV set. I stole filament power and B+ from my Hallicrafters S40B receiver. Later on I used one channel of a stereo tube amp to Heising modulate the pentode of the 6AW8. As I recall, the audio amp had two single ended 6BQ5 audio output tubes. For CW, I actually used this setup on 80/40 and 15m. Good for a few watts! Jim Wd5JKO Title: Re: 5 Watts with one tube Post by: WA4WAX on January 02, 2019, 09:20:33 PM Yet another idea: AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
Match a pair of those tubes on a good tester. Hook the two triodes up as per the Frank Jones push-pull crystal Tx. the pentodes would be driven push-pull. Probably get 8 to 10 watts. Also, have the option of tuning the output tank of the pentodes to the third harmonic.......40 and 15 say. |