Hey gang!
You know, something just struck me after reading all the stuff about
the 11 meter amp shoot-outs and checking out the web pages of the amp
builders on both coasts, there might be something to learn from them.
No, I'm not kidding. Example...
With the 3 tube 3-500Z amp shown in the pictures, how is the high
voltage developed??? Who supplies the power supplies for these rigs?
Are they built by the same guy who makes the amps???
The reason I ask is a bit unnerving to mention but, back when, in
the 70's during the big CB craze, I was working as a salesman in a CB
shop. There was a fellow in Kansas who was making BIG (at the time big)
mobile amps for Amateur 10 meter (CB) use that used a pair of 3-500Z
but, the power supplies were made by Linear Systems and it took 4 of
them to make this thing work. The filaments were supplied by a pass
transistor/regulator system at some adjustable voltage range to the
required 4.95 to 5.00 volts and a smaller on board supply make up the
cutoff voltage for the amp but the HV was external and made up of the 4
ps. Not a cheep proposition as the 4 power supplies came to almost $800
back then! That amp was driven by a 4 tube (sweep tubes) mobile amp.
About 1500 or so watts mobile on SSB! Ok, so that doesn't look like
much by comparison but it is still an accomplishment.
From a modern perspective, there is no mfg. of these power supplies
available that I know of so how do they make up the HV today??? Could
be useful information for future mobile amp projects.
Oh, btw, my own mobile amp for 20 and 40 meters back then was made
up of 6ea. 6LQ6A with the fills wired in series parallel and using 3
used Galaxy GT550 mobile power supplies in parallel to supply the
current. About 1kv at about 1.25 amp DC input gave me something in the
range of 750+ watts output when driven by my old Galaxy III. Sure made
some nice sparks fly off the ends of the whips when conditions were just
right/wrong!!
So, if you fellows don't mind sharing some of your knowledge with
some of us power impaired hams, how about it??
Mike Baker KØQZ
former KAI-6510
former KAKP-7605
back when there were only 23 and I had only 6 in my ole Johnson
Messenger I
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