[Amps] ARRL Amplifier book

[Will Matney <craxd1@ezwv.com>]

Phil,
Another good source of big amps is from Henry and others used in RF 
heating applications and in wafer processing (semiconductors). They use 
these where they do brazing, and heat treating of smaller parts that can 
be fit inside a RF heating coil. I forget what frequency they run at but 
know they can be converted to 10 meters easily. There is one problem 
with some of the Henrys though. They made the load and tune capacitors 
out of a copper sheet with a teflon sheet insulator forming a piston 
capacitor. The tank coil and the back sheets on the capacitors or hot 
with plate voltage. The coupling capacitor is between the load capacitor 
and the output cable. these are generally built in rack chassis with 
huge power supplies and a driver circuit which is generally solid state. 
Rip out the capacitors and change them to vacuum variables. Change the 
coupling cap to be between the plate choke and the plate tune cap. Add a 
new set of coils, a band switch, and your set. Believe it or not, these 
can be bought pretty darn cheap with good tubes.

I suspect that they are afraid of litigation...if they publish a

design

> > for a QRO amplifier that uses more than 12 volts and someone builds
>  
it

> > and gets killed, they could be a target for a dumba** lawsuit.
>  

That probably has a lot to do with it, Vic.

Generation X and later has been raised on 240 VAC and 12VDC.

Articles and handbooks targeted at amateur radio operators have been
"politically correct" for many years, since tubes were invented.
Bill Orr is the only one I recall that has published projects with
tubes that exceed 1000 watts dissipation.

A little history here for you younger folks under 50.....after WW II,
a treasure trove of equipment and parts was available from "Army-Navy"
surplus houses all over the country. Books were published on how to
convert the gear for civilian use. No one, to my knowledge got rich
off the sale of these books/manuals, but they made a fortune for the
big surplus houses in moving their inventory. A kid like me in the
'50,s
could buy a brand new surplus Army transmitter for c. $5.00, build a
power supply robbed from an old Muntz TV set, and be on the air on
a paper-route budget!

The new "toys" of the 21st century are the big amps from Collins that
are coming out of the old Nike missile silos, Big Henry amps that
came out of U.S. embassies from all over the world, Harris amps that
came out of the bowels of ships by the hundreds, broadcast and
medical "pull" tubes, MRI machines, and so on. There is no market for
authors to publish their conversion projects on all this wonderful
stuff, because of the capabilities of the gear....a little bit too
QRO, and the fact that there are too few of us interested parties left
on the
planet that would buy such publications. Our savior might be the
internet, if some web host has the time to collect all the data and
put it up.
Rich Measures et al  have made a good start on this

When I was a kid, I could only dream of a legal-limit station. I would
go out to the Army Corp of Engineers office at our local lake and
drool
over the Collins KW-1 for hours. Kids nowadays drool over entirely
different things. This reflector is so valuable in putting folks
together to
get their projects up and running.

Just a few ramblings from an old-timer witnessing amateur radio as I
knew it getting more obscure every day.

(((73)))
Phil, K5PC


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