In article ,
t.hoehler wrote:
I wonder if there are any 50KW AM vacuum tube transmitters in use
anymore?

They are certainly dwindling. I've visited a few sites that still
have Continental 317s active, but for the most part these transmitters
are being retired rather rapidly now, in favor of new Harris and
Nautel solid-state units.

The situation is less clear on the UHF-TV side. Many high-power UHF
stations still use Klystron-based transmitters, and newer high-power
installations still use tube-based transmitters.

-GAWollman

--
Garrett A. Wollman | As the Constitution endures, persons in every
| generation can invoke its principles in their own
Opinions not those of| search for greater freedom.
MIT, LCS, CRS, or NSA| - A. Kennedy, Lawrence v. Texas, 539 U.S. ___ (2003)