Just for the record, my 2x4CX250 amp will run 1400 watts out on 144 mhz, as
measured on a Bird 43, and crossed checked with two different slugs. I
could and did run a pair of these tubes on EME for about two years during
my active periods. This included skeds, randoms, and contests. The tubes
ran cool, as measured with thermocouple in exhaust port.
I used A BUNCH of air, ran them in class B, (P-P design) with 2700 volts at
about 800 ma, total anode current. I could switch them to a more
conservative AB1 mode, but since I seldom ran tropo, there was no need to
run anything but CW. (Real hams only transmit one tone at a time!)
When the power out would drop off about 10%, I'd find another pair to stick
in there. Most were used, purchased at hamfests. In the last six years I
was active on EME, I went thru two pairs and the third set is still in the
amp.
4CX250's are real workhorses and are willing to take a lot of abuse.
However, as has been said before, don't try to run SSB under these
conditions unless you have a much bigger gun than your neighboring hams do.
73,
Larry - W7IUV
w7iuv@axtek.com
www.axtek.com/w7iuv
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