Here I am testing a couple of RCA 7213 power tetrodes. These are 1500W plate dissapation tubes which will give 1350W output at 1200Mhz, CCS. They are speced for SSB linear service. The Heathkit supply is for screen and bias. The variac and transformer provides plate HV. This was an emission test conducted at 750V. The tubes had better than 1A of emission which is the max plate current per the spec sheet.
Here is a close up of the tube and socket. The socket came from a CH 6 analog TV transmitter that I had the extreme pleasure to help dismantle. This socket was from the visual driver stage which used a similar tube, the 8792 which is impossible to find used and cost about 8K new. The 7213 seems to be common and cheap as it was used in airport navagation systems. The two I have were $10 on ebay for both. They are both good and matched almost exactly although they were made about 8 years apart.
It took about 4 hours to clean and polish the socket and to cut new mylar bypass rings. This socket is setup for grounded grid with bypass rings on both grids. This is the screen ring, the control grid ring is underneath and looks identical complete with the .01 caps. The mylar rings are cut from 3 mil sheet which has an insulation rating of 21KV! I don't believe it could do that in a real world situation, but I know it takes 1500V no problem. Anyway look to hear this on the air someday.
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