[Boatanchors] Novice Transmitter Thoughts?

[Michael Baker]

Kurt, you left out one of the best Novice transmitters made. (IMHO)
The Drake 2NT. 
Had delayed break in built in,(no external TR relay needed as I recall)
looked good, worked well, I never heard one chirp unless the external VFO
had an issue, used the same sweep tube in the final that Drake was famous
for in most of their gear, 6JB6, (although you could sub a 6146 in any
flavor for the sweep tube).
IF I was going to build something that I wanted to keep and use on the air
for a while I would try to duplicate the 2NT. 
For a VFO I would likely use an inexpensive DDS and a display because they
work so well and you don't have the drift and chirp issues to deal with.
IF I was going with a true "period" rig then a homemade PTO with either a JW
Millen Drive, a National dial, a large slide rule dial or just re-use the
command set tuning unit and a multiplier stage.
Power transformers are not as common as they once were but, they can be had
with a bit of scrounging for reasonable $$, or NEW if you have the $$$ (See
Hammond Manufacturing, they make lots of they for the music industry and
replacement use: Antique Electronic Parts, Mesa AZ carries them along with
lots of other goodies for the "fire fet" enthusiast.  ;>)
Push comes to shove, you can always hook up a few filament transformers in
reverse mode: IE: 120-12 then 12-120 or to two of them so you get 240AC. In
FWB that comes out to 120AC=168VDC, 240AC=336VDC. More if you use voltage
doublers.
Don't forget vintage voltage regulator tubes for that nice "glow" that helps
keep the plates of your oscillator and buffer stable.
Don't waste your time, money, power consumption on tube rectifiers for a rig
of this power level. Just use plain old diodes and be done with it. Big rigs
used mercury vapor rectifiers which look great when running in the dark and
viewed thru either fine mesh metal cloth or quartz glass! 
Depending upon your metal working ability and tools, a vintage rig could
always be built on a cake pan upside down! (Man, was my mom mad at me for
that one! Her bread pans were just the ticket for a QSL 40 rig!) IF you need
room to work, a 9X13 with a slide off lid that can be used as a bottom is
under $10 most places. (The holiday season is just around the corner and
that stuff goes on SALE this time of year!  ;>)  Don't forget to check out
the local Goodwill and Salvation Army stores for treasures in your build!
LOTS of possibilities to consider.
Do give grid block keying a strong consideration if you roll your own rig as
cathode keying can be a PAINFUL experience if you don't use a relay.
(Perhaps Fatal if you got too careless!)
FUSE THE RIG!   FUSE THE RIG!!  FUSE THE RIG!!!  NOT TOO BIG!  NOT TOO BIG!!
NOT TOO BIG!!!  When in doubt, measure, then fuse!

AND MOST IMPORTANTLY, WHEN YOU GET IT READY TO PUT ON THE AIR GIVE ALL OF US
A COUPLE OF DAYS HEADS UP SO WE CAN HEAR YOUR HANDYWORK ON THE AIR! NOTHING
LIKE HAVING A FEW COMMERATIVE QSLS ON THE WALL TO COMMERATE THE JOB WELL
DONE!

Best 72, 73
K7DD
Mike Baker

END  
NNNNN

Michael Baker  K7DD
k7dd at cox.net

-----Original Message-----
From: boatanchors-bounces at mailman.qth.net
[mailto:boatanchors-bounces at mailman.qth.net] On Behalf Of Curt
Sent: Friday, September 10, 2010 2:34 PM
To: boatanchors at mailman.qth.net
Subject: [Boatanchors] Novice Transmitter Thoughts?

Most of the novice transmitters I've been looking at from the 50s and very 
early 60s seem pretty similar in design, differences being the tubes used 
and maybe quality of construction. Not sure how there could be much 
difference in performance, but from reviews in various places, some worked 
better than others.  Maybe the differences resulted from the builder, most 
were offered as kits.  One consistent thread seems to be the marginal 
transformers used in some of the Heathkit transmitters ( only the DX-35 and 
40? ).

When I was living those times, the only rig I cared about was the one on my 
desk, an Eico 723.  What I'm curious about is what the conventional wisdom 
is/was about the following rigs, and how performance generally compared with

say an Eico 723:  Viking Adventurer, Globe Scout ( which of the models was 
"best"?), Knight T-60, Heathkit DX-20 ( nearly a clone of the 723?)

73, Curt KB5JO

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