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Author Topic: 5 Watts with one tube  (Read 3009 times)
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WA4WAX
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« 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
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W8ACR
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« Reply #1 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.
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K2FW
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« Reply #2 on: December 30, 2018, 06:31:54 PM »

A wonderful archive of Radio Magazines in PDF Format.

TKS!
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WA4WAX
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« Reply #3 on: December 30, 2018, 08:40:21 PM »

Maybe an LM380N and a backwards audio transformer.

No tube.....that may upset some.

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KD6VXI
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« Reply #4 on: January 01, 2019, 11:46:32 AM »

I'm thinking push pull 4-65s.

Headroom, ya know?  😂🤔👌

--Shane
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WD5JKO
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WD5JKO


« Reply #5 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
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WA4WAX
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« Reply #6 on: January 02, 2019, 09:20:33 PM »

Yet another idea:
 
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.
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