On 5 Jun 2005 17:13:48 -0700, wrote:

[snip]
Western Electric 416s and 417s are out there in larger
quantities.

Hmm. I used several of these in two-meter receive pre-amps, but never
considered them for the finals. I did have a little blower on the
416B tho.

I know that W-E used them in transmitters but I never saw any ham
designs doing it.


Geez, 829 duals have been used at 144 MHz
with more output than one can safely run a 2C39 at that
frequency. Socket assemblies for an 829 are easier to
get than for an inverted lighthouse structure.

Had one of those on two-meter CW/AM. Used the modulated high voltage
out of my Heath DX-100 to run it.


A year or so ago I happened across a couple of non-USA
sites giving nice details of 2C39s used in ham VHF
transmitters. Nice photos and dimensions available.
Both of them used the triode "pushed" beyond its safe
limits of power. Think about replacement costs.

The 2C39 is often converted to water cooling, and really pushed.

http://www.w6pql.com/200w_23cm_amplifier.htm



At 2 meters, a better way using vacuum tubes (besides
going to Eimac goodies) is in a "distributed amplifier,"
the grids of many 9-pin tubes connected to an L-C
delay-line-like structure, the plates connected to another
L-C network. The Tektronix 540 series scopes had those
for the vertical amplifiers, good beyond 50 MHz, back in
the 1960s. No tuning required...except in how to couple
the medium-Z output to a low-Z antenna.

I wouldn't call this a better way unless you live in a cold climate
and need the extra heat in the shack.