>I am contemplating a first attempt at building an amplifier. I am
>thinking of one that could produce a half KW (or more)on all bands from
>160 through 10 meters, be seriously rugged with a heavy duty cycle, and
>yet be made of parts that are readily available.
>
>I have been reading the posts to this reflecter and have been most
>impressed with the kind of knowledge possesed by several participants.
>
>It has become more and more difficult to find interesting projects with
>which to enjoy this hobby
amen
>(I've built so many antennas), that I thought
>assembling an amp would be interesting, educational, fun, and result,
>hopefully, in a very usable piece of equipment.
>
>I would sincerely welcome everyone's input. What type of tubes,
I have some unused Eimac 5-125B pentodes I will donate if you pay the
freight. The rating is 200mA each. The filament draws half as much
current as a 3-500Z -- 5v@7.5a. Although the 5-125B may be used in Class
AB1 grid-driven service, I recommend g-g service. The socket is the same
as for an 813, which is available at swap meets. In RTTY service, one
tube will put out around 240w max.. In SSB service, one can put out
around 380w max. . . At 4kV, the drive requirement is about 25w per
cathode. Less anode supply v means more drive needed. A 5-125B is
fairly exciting to watch doing it's job. It uses a tantalum anode. At
full throttle, you can read a newspaper by the brilliant yellow-white
light from the anode.
- Some amplifier design info is on my Web site.
www.vcnet.com/measures
cheers, Doug
Rich...
R. L. Measures, 805-386-3734, AG6K
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