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Tubes from TV-repeaters used for EME on 1296MHz
Category: EME Equipment,
Created: 2007-12-21 20:36:35
commercial applications for television power amplifiers use increasingly solid state solutions.
Amateurs still can use so called pulls for serious power. This is not too critical for 432MHz but 1296MHz is far beyond the specified frequency range of the most popular tubes.
Testing pulls Thomson TH347 an TH327 delivers typically 1 out of 10 with gain >9dB. A few out of 10 deliver 8-9dB and 5 or 6 are not usable on 1296MHz. The tube specification is max 1000MHz so these results are not really surprising.
Many in- and outs of a tube in a cavity may rotten the fingerstock. I am using separate amplifiers for tube testing and would not use the eme equipment for this purpose.
The Thomson TH308 and TH328 series are typically still very useful on 1296MHz.
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