[600MRG] How tough are your tubes?

[Ralph W5JGV]

> Did your loading coil melt ;)

No, because there was no RF drive at the time. so ALL the DC power went
to heat at the anode.  Luckily I believe in lots of cooling air on big
tubes.  The amplifier was supposed to be in idle mode between beacon
transmissions. Plate dissipation should have been about 300 watts at the
time. It has to stay in Class AB mode to be linear, and I just leave the
plate voltage on 24/7. Lot'sa heavy duty operating hours on that bottle
by now, I think.

 > You always have the most action packed stories to tell us. Glad it
didn't go bang or start a fire.

No, THAT happened a few days ago... when the solid state amplifier blew
up. I have been too busy to repair it. Anyway, since it’s winter, I can
use the heat in the shack. The building heat is electric anyway, so I
might as well run the Big Amp and let the electrons do some useful work
making RF on their way back to the power company.

...I wonder if I can redesign the RF amplifier that I built for my Rife
system to run on 600 meters? It can output  500 watts CW on 3.1 MHz from
a single MOSFET. In bench tests I had it up to 1000 watts output for a
few minutes. It weighs 10 ounces and requires 8 watts RF drive. It's a
switch mode circuit, and puts out a half-sine wave, so a big filter
would be required. No way to make it linear, though, but for CW, it
might work. It sure drives the big Rife tubes nicely though!

73,

Ralph  W5JGV - WD2XSH/7