Wow, this mailing list does work well, for unique data. I got >2
responses for the Harris RF103 schematic and transformer info, and
today Posselt, OE2WPO, emailed me a PDF of the manual. Gerald, W5BA,
was also preparing something to help. Thanks guys for the help and I
am off to build a nice HV PS from that pig of a transformer. I got a
Chippewa last month, that needs 3 kV at 1/2 amp or so, pair 4-400A's.
I am already using SB220, so I don't need another operating amp at
home, but I wanted to play with tetrodes for a while.
So thanks again for the response. To me its stuff like this which
actually make AMPS.CONTESTING quite useful, not continual bickering
about CB vs Ham or Parasitic theories for triodes.
I will pose a work-related technical question for the solid state RF
power experts. What is the biggest or highest power MOSFET device I
can get for linear (AB) operation at 200 MHz? Am already using a
crate full of parallel and combined MRF151G devices to get 5500 Watts
pulsed. I see that PolyFet has devices, M/ACOM (Tyco!) has the MRF
line, possibly Ericcson (sold off?), ST Electronics, Semelab.
Others? Seems that the practical limit for Standard V or D MOS is
about 400-500 watt dissipation devices. The HOGFET (MRF154) wasn't
rated above 100 MHz, and thats pushing it. LDMOS isn't really pushed
for VHF range, and I would rather stick with MOSFETs. Most solid
state TV transmitters seem to use the 151G, and the MRI/NMR
amplifiers may also. I look forward to hearing some good discussion.
(fyi, I need 16 kW peak at 200 MHz, with 15% duty factor pulsed to
drive a tube).
73
John
K5PRO
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