>
>I have not been able to coax 36 kW out of 4CX15000 in class C, but
>have gotten 35 kW out of 4CX20,000A/8990 tetrode. It took about 400
>Watts of drive and screen voltage turned up, and can be found in the
>Broadcast Electronics FM30B transmitter, at 100 MHz. At lower freq,
>it may be possible to squeeze a little more, but I am wary of claims
>of such power from a 15K - frankly all of that does sound a bit
>hogwashy.
? An 8281 / 4CX15,000A will run about 66k input on SSB.
> If someone does, it won't be very long lived I think. I do
>like the idea of Richs of "using an 8973 running 22 kV etc etc."
? The 8973 story was a parody.
>Would LOVE to see anyone try and tame that tube in a homebrew job!
>
? A friend of mine saw a tube and socket for sale at a salvage yard.
........ Driving an 8973 would not be all that hard. Grid potential
runs about neg.380v in AB1. Thus, you could drive one with a SB-220 or
TL-922, using a 50-ohm grid termination. The grid roller coil would need
to be good for about 10A. 2kV is all it takes for the screen. The
positive floating regulator on my Web site could do this job. Problem
areas might be the 700A water-cooled tank inductor, and the 1.4MW needed
to power the beast. You would need a 100A service .............. @ 16kV.
The good news is that you would not need a hv transformer. // Power
gain should be a bit over 27dB.
A ham pal of mine was recruited by the FCC in his senior year at Cal
Berkeley. He eventually rose to Field Engineer at Denver, CO. . He
told me that confiscated CB amplifiers were tested for courtroom evidence
at a goverment warehouse/lab facility in Virginia. A wide assortment of
commercial three phase and single phase power was available. However,
one confiscated amplifier was not tested because not enough power was
available at the site. .
cheers, John
- Rich..., 805.386.3734, www.vcnet.com/measures.
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