My first project was a pair of 6L6s driven by a 6AG7 on the novice
bands. I built it on the corner of an old TV chassis in 61. In those
days a B&W TV PS was as robust as a Collins PS. It looked crude and
rough but it worked fine.
My second project was rebuilding a 6C21 into a pair of 813s. You could
purchase all the "good" 6C21s and 813s you could afford for $5.00 ea.
Unlike now days, a gassy 813 was rare. However, that was in 61-62, or
abt 55 years ago
The PS didn't even have a cover, but was well out of the way, so I
couldn't put my feet on it. OTOH I had courses in electronics, TV, and
Instrumentation, so I was comfortable around HV. OTOH, I was 21 before
getting into Ham Radio. I had learned the CW in Boy Scouts, but that
had been so long ago, I had to learn it again. 5 WPM was easy. 13 WPM,
not so much. I spent a lot of time on CW after earning the General
class. I'd tune in a good sounding conversation and stretch out on the
couch. Before long, high speed CW was like listening to someone talk.
73, Roger (K8RI)
On 1/6/2017 8:17 AM, Jim W7RY wrote:
I completely disagree!
My first amplifier project was at age 16, shortly after I got my
general class license.
I modified (and extensively at that) a amplifier that was homebrewed
by someone else. I removed the choke in the power supply, converted it
from tube rectifiers (3B28) to 1N4007s that I bought from James
Electronics, built a tuned input circuit, built my own high voltage
probe with 1 megOhm resistors and used it with my Radio Shack range
doubler voltmeter, and then used it extensively on 40 meters SSB on
7235. AND lived to tell about it! But then again, I'm very confident
around high voltage.
And this was in 1961 give or take. About 55 years ago. The 3 leg
fuses were just on the horizon.
73
Jim W7RY
-----Original Message----- From: sm0aom@telia.com
Sent: Friday, January 06, 2017 1:18 AM
To: amps@contesting.com
Subject: Re: [Amps] Decline of homebrewing?
This was written almost 50 years ago, and gives some food for thought
even today:
"Homebrew Kilowatt
Dear 73,
Did you ever write an article that you later wished
you had not written? I have written several. The latest
is the 6KG6 KW amplifier appearing in January 73.
The third paragraph states, "It is assumed that the
ham who starts out to home brew a kilowatt is not
embarking on his first construction project".
You wouldn't believe the letters I have received from
neophyte hams, who, by their very questions, reveal
that they have never built anything at all. So suddenly
they decide to build a KW with 2000 volts on it.
I sincerely hope nobody gets electrocuted as a result
of my article.
I belive you need a good article entitled, "If you
want to get your feet wet, start at the shallow end of
the pool". Then go on to describe a good linear (or
other amplifier) that has a supply of less than 500
volts. Go through it piece by piece and explain what
the parts are for and why they have to be within
a certain size range. The stock question about the
above amplifier was "What's the size of the capacitor
between the plate and the pi-network? This is noted
in at least ten places in every handbook in the land.
A ham who doesn't comprehend even vaguely, the pur-
pose and limitations of a dc blocking and rf by-pass
capacitor, has no business building anything as lethal
as a KW final,
R. D Baird W7CSD
Klamath Falls, Oregon"
73/
Karl-Arne
SM0AOM
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