Some years ago when I was in the 9th grade I started building
my first Ham transmitter. I wanted a Viking Valiant for Christmas
but parents could not afford such an expensive transmitter.
I designed a TX with a 6AG7 crystal oscillator (had a HG-10B vfo also)
a 6L6 buffer multiplier and a pair of 6146B's in the final. The 6146B was
a new tube then. It would run about 200 Watts plate input power. One fifth
of the legal limit those days.
My parents had a charge account at one of the electronics distributors
in Nashville and I talked them into funding the project. "It was going
to save them money", I said.
Now I realize that my parents made the best decision possible.
Not to buy a higher power transmitter but to allow me to design my
own and learn from it.
Well, some months later it was still not working and I had gone
quite a bit over budget. My father came down to the shack to see
what I was up to after receiving a bill from ELECTRA Distributing Co.
He asked what I was spending so much money on.
I told him that I seemed to make one mistake after another and
had to replace a number of components that burned out while testing
the TX.
He then said." Making mistakes is not a bad thing. You can learn from
your mistakes. Just don't learn so much at one time."
I never forgot that conversation.
The transmitter worked just fine finally. The next year I entered
it into the science fair and only got an honorable mention. The
judges could not believe I had done it all by myself even after
interviewing me and discussing it with my science teacher.
I'll have to admit that I learned a great deal from this experience
and later I discovered that I could build transmitters from all sorts
of used parts from old televisions, radios and junk dealers around town.
I also did a great deal of horse trading with some hams for parts.
For the next science fair I added a plate modulator that I had built and
worked my way up to 3rd place. Again they could not believe I had built the
thing by myself.
Later I got a Central Electronics 10A sideband exciter with the modified
ARC-5 for a VFO. That then drove my 6146B's.
During a trip to Florida I got an old transmitter with some 813's and salvaged
the power supply and used my 6146B's to drive a pair of 813's. The place I got
it from was HS Electronics in Miami. HS I think stood for Ham Shack.
A friend of mine W4WHB sold me his HT-4 which was the civilian version
of the BC-610 with loads of spare tubes. Being a collage kid by this time
and eager to get more power I scrapped it and built a amplifier with a
pair of 250th's in grounded parallel. They worked just fine. I tried to
run 3 of them but the 6146Bs just were not up to the task. Not enough drive.
Now I just wish I still had the HT-4. They are quite a collector's item now.
I paid $20 for it and about the same for the 813 transmitter.
After that I had moved up to the 20A exciter and build the big power amplifier
out of a 4-1000A. I had a power supply with a tapped auto transformer that
would give me any voltage from 2KV to 15KV. Never ran it in to a amplifier
at more than 5KV. But I did run it up to 15KV with no load just to see if
it would do it. Those mercury vapor 872As really lit up.
My mother would just come in to see the light show when I was on the
air and had the lights turned out. The plates of the final tubes would
glow red on voice peaks and the rectifiers would make a neat pulsating
purple glow as well. That along with the pulsating hum from the power
transformer (amplified by the floor boards ) really gave a ham a
sense of POWER. I'm looking forward to building a new amplifier and firing
it up. Just have to find the spare time.
While other guys were hot rodding cars I was doing ,more or less, the
same with my ham station. Really had a good time fooling with RF stuff and
now days still do. Really do a lot here at work. It is truly amazing how
much RF technology is used in physics research and astronomy.
73
Bill wa4lav
PS I am now building another 4-1000 amplifier.
William L. Fuqua III P.E. E-mail WLFUQU00@POP.UKY.EDU Phone (606) 257-4155
Department of Physics and Astronomy CP-177 Chem. Phys. Bldg.
University of Kentucky , Lexington, Ky 40506-0055
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