RadioBanter - View Single Post

From: (Jeffrey Herman) on Tues, Jan 3 2006 6:57 am

On 1 Jan 2006 16:52:58 -0800, wrote in

Now, if you want to "build from scratch" totally, you
will have to learn to SUCK all the air out of the tubes
you build for yourself (honoring the "tradition").
That's rather difficult (truly, vacuum sucks)...but
much, much easier than first creating ultra-pure
silicon and then doping the microscopic areas on it to
become the solid-state device you need. [sorry you
can't build "spark" transmitters...those being forbidden
in these modern times unlike a hundred years ago]

There was a fellow who did construct his own tubes. See the
publication "50 Years of ARRL".

Jeffie, if it's all the same to you (and it won't be),
I'll just "see" some professional documents from RCA, GE,
Raytheon, Westinghouse, etc., on "constructing" tubes.
They've had a few years of experience in that, wouldn't
you say? I'd have to travel a few thousand miles away
to get most of that info and there's little return-on-
investment of my time to do that in order to satisfy
a league Believer. Not this week for me.

Frank Gilliland thoughtfully provided a link to an
EXPERIMENTER'S website on the "constructing" of tubes.

Further, having been in correspondence with G0UPL in
the UK, I have some further links (and some interesting
downloads) on making one's own glow-discharge numeric
indicator ("Nixie" tm of Burroughs Corp.) displays.

All that might be academically intersting to leaf
through to some...who will probably never ever pull a
good vacuum for any purpose (other than getting a
vacuous response in newsgroupie-ism).

I really DON'T think it is interesting to me to know
all about "constructing vacuum tubes" as given by some
amateur radio membership organization publication.
Tubes (vacuum tubes, that is) can still be purchased
where needed for replacement purposes. The cost is 5
to 20 times what it once was (depending on demand), but
then there's not much of a demand for those things.

"Constructing" a vacuum tube innards is relatively easy.
The truly difficult part is pulling a good vacuum on the
bulb and getting rid of extraneous gasses within. Now,
I've had some slight experience on "pulling a good vacuum"
for testing purposes and that requires considerable work
and expensive equipment. [Torricelli would be amazed at
the processes used over a half-century ago in production
vacuum tube work]

Better yet, Jeffie, why don't you get REALLY "build-
from-scratch" and go mine natural quartz in Brazil,
then bring it home to the islands and slice it up to
the right crystal angle, grind it down to the right
thickness, measure it to better than 10 PPM in
frequency, mount it in your own holder, and use it for
your super-spay-shull build-it-yourself super-duper
QRP transmitter for use in the year 2006?

Gosh, I think re-visiting the 1920s in amateur radio is
such great fun in building-it-oneself, don't you? :-)

I'll bet you even have a forge and an anvil so that you
can make horseshoes for your land transport. Real do-it-
yourself projects with a practical side!

Have you slaughtered and skinned animals, cured the
hides, sewn the leather pieces together to make a saddle
for that land transport? Does the ARRL have a
publication covering that? Why not? The Army Signal
Corps designed and had Motorola make a "horse mobile"
two-way HF radio in 1943. It was called "the pogo
stick." Of course the mounted cavalry was disbanded
before production was finished, but that's another
story entirely.

Start preparing for your regular work. Classes begin
on 9 Jan 06, don't they?

Thank you ever so much and buy, buy,