Well to answer the replacement question - according to GE Industrial Tube
Products Guide - (Dated 9-79)
You can replace an 829 with an 829B.
You can replace an 829A with an 829B or an 3E29.
You can only replace an 829B with another 829B.
Why? I don't know, that's what GE says.
Now what an you use an 829B for? Well I got one, it was a spare from a GE 6m
Prog Repeater our club had on the air. The replaced it with a nice Moto. The
Prog was up for grabs but no one wanted it and was about to be hauled to the
landfill so I took it.
It lasted about two days in my house working fine. Then I put it out of it's
misery and parted it out. It had lots of juicy power transformers, tubes and
sockets, XTAL holders and so on. Most ended up in other projects or repaired
rigs except for the 829B.
What to do with it ???
I decided to build a one tube 40 Meter CW transmitter.
Nothing special about that - all of us have built 6L6's or 117L7GT, 6V6,
6C4, 6GW8 or you name it peanut whistlers. Nothing more than an oscillator
connected to a string (antenna) blasting out a few watts.
But how about a SINGLE tube transmitter pumping out 100 to 115 Watts !!!
With minimal parts count to boot!
I got the idea from QST - June 1940 (page 26) in which Fred Sutter W8QBW
describes a transmitter using -TWO- 6L6's in push-pull supposedly outputting
100 watts to an end-fed Zepp.
I'd take the 100 Watt claim with a little grain of salt... but it's still
not too shabby for 12 parts and 2 tubes not counting the power supply.
The 829B can replace the two 6L6's and the circuit can be adjusted
accordingly. The output tank circuit will be PI instead of link which was
common back then. I also have a nice power transformer that looks like it
can do 700 mils at 750 VAC so I have plenty of head room to crank out more
power if it can handle it and the XTAL doesn't shatter.
I'll use forced air cooling because the 829B socket is already designed for
it. Was gonna go with a fancy blower but I noticed the XYL is not using the
small Dirt Devil handVac I gave her for her birthday. Will cut a small hole
in the chassis and placed a PVC pipe and attach the air hose to that. RCA
Manual says the MAX glass temp is 235 F so hopefully, the plastic vac can
handle it.
For a Glass Chimney, I took a drinking glass and cut off the bottom with a
glass cutting wheel. I was rinsing out the dust in the sink when she spotted
me. I told the XYL I had just taken out the glass from the hot dishwasher
and poured a little bit of cold water and the glass cracked and the bottom
fell out. I hoped she didn't notice the ends were nicely smoothed.
You should have seen her face. Classic...
It's the same look I get when I bring in another hamfest surprise and
promise it's the last radio I'll ever buy because my radio collection is
complete - excuse.
Well anyway - A single Tube 100 Watt CW Transmitter - that's my 829 project.
Have all the parts - now waiting for the weather to warm up so I can get to
work in the Garage.
You just know if she sees that tube chimney and her Dirt Devil, I might just
have to sleep there too.
-Biz WDØHCO
I posted a picture of my 829B on alt.binaries.pictures.radio for those who
have never seen one.
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