[Amps] TV sweep tubes and 6146s

[Peter Chadwick]

Back when I had almost limitless supplies of 6146Bs, I ran a pair at 1200 volts on the plates. They lasted well, provided you didn't run steady carrier, and gave about 180watts PEP out with 3rd order IMD at about -28dB relative to PEP. They were rated in plate modulated Class C servicve at 600volts on the plates, so had the potential to hit up to around 2400 volts or so peak. This suggests that pushing them much beyond about 1400 or so would probably be dodgy. However, at that , you copuld maybe get 400 watts or so. On the other hand, some of the transmitters we did with 3 6146Bs and about 800 on thenplates would hit 200 watts PEP out at -27dB rel PEP third order: others would only hit 100 watts at the same IMD. Of course, there were variations in the driver IMD to consider, too.

Incidentally, I'm not sure I completely agree with all K9STH's comments on 6146Bs. Tx's that I've designed have got down production lines in enough quantities to have used over 10,000 6146Bs in their construction, so I figure I can claim some experience.

73

Petere SM/G3RZP/P