Well, I see we have another panix subscriber in the group. Yeah, I liked
those old tube radios as welll. I am blind, and had a hard time tuning
them up at times though.

On Wed, 22 Aug 2007, Straydog wrote:


Changing the subject but stayin in the thread... (see below)

On Mon, 20 Aug 2007, Mena Mike wrote:

Well folks, since I have been licensed since '56 I know all about those old
rigs. As it is, I do not own, nor will I buy any modern equipment, even
today. I have mostly all Drake gear, and a set of Kenwood twins. It is the
later version (T599D and R599D), but they still have three tubes in them. I
can still remember my first transmitter that was my Christmas present in
Dec. of '56. A brand new Heath DX-35. I used a 1937 Hallicrafters SX-11
that cost me $15.00. I had done WAS with only three crystals by the time I
graduated HS in '57 and joined the Navy. I still like the wait for the rigs
to warm up, keeps the shack warm in the winter and has that great smell of
burning dust off the tubes from time to time. We didn't even know what SWR
was, and had no way to measure it if we did. Use the handbook for your
measurements, cut the wire and build and antenna. If I remember right, I
even used RG-11U for a feed line, not knowing any better.

Yeah, keep 'em glowing... Plug-N-Play is not for me!

As I recently became retired my interests have evolved towards building
homebrew tube gear. Reasons: i) simplicity in circuitry, ii) comparatively
large tubes & sockets make soldering easier, iii) accidental slip of the test
prod might not kill a tube but might a transistor, iv) yeah, I like to see
those filaments glow, too, v) can still get those tubes but some transistors
you can't find anywhere, v) throw-away technology (boards) is bad
ecology...give me discrete devices any day, and vi) with high power heat
sinks, silicon compound for conduction of heat (if it gets on your
fingers, its hard to get it off) is needed and that damned metal can
getdamned hot.

I've been building a tube SSB transmitter for about 1-2 years now (parts of
it can be seen at http://www.panix.com/~asd) and ends up with a pair of 813s
in grounded-grid, driven by a single 811a in G-G, lots of home brew antenna
tuners, and Icom 707 for the moment SSB transciever.

The homebrew SSB exciter lineup is not yet pictured, but at its current stage
of construction is almost ready to go on the air. Generate DSB at 2 mHz with
6AL5 balanced modulator, upconvert by mixing with 7 mHz to 9 mHz
(6BE6), use McCoy 9 mHz crystal filter (somebody gave it to me 25 years
ago) to shave off the desired sideband, mix (6SA7) with 5 mHz local
oscilator (by doubled 2.5 mHz from old war surplus Collins 70H3 VFO [from
Fair Radio Sales when they had them, they ran out years ago]) to get 4 mHz
(75 meters, my favorite ragchew band) which the scope shows to be about 5-10
mv, and goes into two 6C4s (triodes, grounded cathode) and then into
a 6AG7 & 6146. I am at the point where I need to make a RF transformer
to take the output of the 6146 to drive two more 6146s in parallel to get
the ten watts I need to drive the G-G 811a. Yes, if I could optimize
everything better, I could use less tubes. But, I preferred to make
modules (lots of stages are built inside of old computer power supply
cabinets (they are about 6x6x4 or so, and nice to work with, cheap at
hamfests at $1 each or so). All the gear is full of those old D'arsonval
"Frankenstein"-type (real) meters (not this LED crap), so I can keep
monitoring practically all the voltages on anything. Its not very pretty to
look at, but its a whole lot easier to work on than any of that new gear out
that surely has thousands of transistors and hundreds of chips (?).

I chose the 813s and 811 and GG amps because both the 813 and 811 don't
really need cooling fans (I hate blower/fan noises) and grounded-grid amps
are notoriously stable (no neutralization headaches), and they are pretty
cheap. I have several 813s, some made in China; one of the Chinese 813s had a
filament that opened up on me all by itself after very little use (don't know
if that is THEIR quality control or just a statistical fluke, but I thought
I'd pass that along to y'all). I also manage filament warmup and cooldown on
the 813s with a variac (up and down over abut 5-10 seconds), but not on the
811 amp. Been using the 813s + 811 for over a year (using the Icom 707 as
driver) and just love how nice and quiet it is without fans/blower noise.

Almost all of my old rigs are also pictured on that URL, and a couple of
pictures of my "secret lab" out in the garage (heated with a space heater in
the winter, cooled with a small airconditioner in the summer).

I started as a novice in 1959. Had a Knight kit T-50 and Knight R-100
receiver, later got a DX-40. Mostly liked to ragchew with locals on ten
meters AM at the time. Lots of find memories. Lots of SWLing.

I'd like to hear from other homebrewers, HFers, ragchewers and learn if ther
are any 75 meter nets for homebrewers/tubers/etc. I look at all this new gear
coming out (for thousands of dollars) with hundreds of buttons, knobs, and
"thangs" on them, and big thick manuals you have to read to figure out how to
push the buttons (once, press twice, press and hold?, press and hold one,
then turn on the power switch? Etc? Secret "reboot" buttons hidden somewhere.
Built in DRM, DCMA, spyware? Too?). What happened to old-fashioned skill? 50
years ago guys worked the world with a crystal and a single 6L6 and straight
key. Now, they are all couch potatoes in front of a black box that looks like
its from outer space. ;-)

I figure I'm within a week or two of getting the homebrew SSB exciter
actually on the air. I've been testing the outputs of various stages either
using the Icom 707 as general coverage receiver, one or two oscilloscopes to
check generated signals, etc. Still have a lot of tweaking to do. Its been a
ton of work, debugging and rebuilding when something doesn't work, but its
also been an incomparable sense of accomplishment, too, when I get a stage to
work and make progress (four steps forward, three steps backwards). Its also
nice to have some test equipment (generators, meters, a good oscilloscope
[had a Tektronix 922 that gave up and I tossed, then a heathkit which had a
dead vertical amp that I fixed, and a BK-1420? very nice but now the
horizontal sweep died but vertical amp still good, so I can probe at least
for RF which gives me a vertical line [keeping the test equipment going is
also a problem], and all of that stuff is also 30+ years old).

After that, I plan to build a tube receiver and maybe even build a crystal
lattice filter, and try to build a stable VFO.

Art, W4PON
Member, QCWA
~99.9% of my time with soldering iron & screwdriver, 0.1% of my time in
ragchewing.



73 to all
Mike/K5VSE


--
Formerly WB6VSE, Senior Tech. Amateur Division
SBE/Linear Systems, Watsonville, CA
Pupule384 On 3922 Nightly
WEB Site: http://members.tripod.com/~sjsharks/index.html
Restoring and using Drake Radios, TR-4, TR-4C, RV-4C,
Drake Twins: "C" line, W-4 Wattmeter, L4-B amplifier
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