Notice this post was in 2004 but who knows if you still are interested. I was in the Coast Guard and the 7C23 was the main amplifier in the Loran A Transmitter. The standard transmitter used 4 x 7C23, and produced 167KW pulse power. There was also a 1MW amplifier (rarely used) that had 16 x 7C23.

Here is a link to the spec sheet. http://tubedata.tubes.se/sheets/167/7/7C23.pdf

The 7C23 is not easy to used. It must be mounted on a ceramic column with a metal ring with a forced air cooling source up through the column. The plate is also the outer metal case and needs 15KV source. Hence the ceramic column. The metal ring provides the plate voltage. The rest of the connections are made through the connector.

Arcing is a major problem. Also, the 7C23 requires about a 8 hour bake in with the plate voltage gradually being increased.

With 15KV on the exposed plate, major forced air cooling, the 7C23 can be dangerous and difficult.

Honestly, the 7C23 makes a better paperweight or curiousity object.