Hi all,
I am new to the list so be kind! I went through all of the threads
on amps@contesting.com concerning an amplifier using 833's and pretty much
came up with very little usable information. Why 833's? Why do I still
deer hunt with a muzzle loader with just iron sites? Why do people still
build tube regens? Just 'cause I guess it is a challenge and the 833 is a
magnificent looking tube all aglow!
I was an Electronic Design Specialist for Ohio University for over
22+ years and have built a hybrid solid state 160 meter SSB/CW 100 watt
transceiver (Using a pair of 6146's) from the ground up, (
http://oak.cats.ohiou.edu/~weinfurt/160mrindex.html )including a 500 hz CW
filter. Age is mid 50's and was in Tube/Solid State transition during
college years. Yep, slip sticks to calculators to SMD's. BSS (Bachelor of
Specialized Studies in Shortwave RF Engineering) is from 1994, so that and
being an EDS helped keep me in the loop until I recently retired.
I have all the parts to put together 160 meter single band
amplifier. I realize that it is a low mu tube of about 35, and would
probably not make a great grounded grid tube... but maybe at 160 meters a
pair of them could reach legal limit with less than 100 watts input?
I have 5 each of 833A pulls, with only 6 months of use. I got
these from the engineer in charge and he said that usual pull time is at
least over a year or unless some failure occurs. But, the owner of the
station demanded that he do it every 6 months no matter what the condition
and he kept the 'like new' ones. Yes they are old, 20 years or so.
I would prefer help from someone who has actually used the 833 in
some type of RF circuit. But anyone with engineering experience with a
behemoth of this type knowledge would be great! I plan to set up a web
page and with my progress to keep those helping informed of my advancement
into the past!
Characteristics for the 833A are
at: http://oak.cats.ohiou.edu/~weinfurt/833A.pdf
************************************************************************************
Plan.
1 Two of them in parallel or Push-Pull?
2 Grid driven with a 55 ohm, 75 watt non-inductive resistor to ground.
3 Pi output network or Pi L ? Or Link coupled output?
4 Operation is CW and occasionally SSB. Bias voltage on Cathode developed
across about 60v Zener to ground?
5 Power supply is capable of 3000 VDC at 1 Amp.
6 Forced air cooling up from pressurized bottom chassis to box on top
housing tubes and output components.
7 Tubes mounted in vertical position. Heat sinks for pin connections.
Greg Weinfurtner AEE BSS
NS8O
40192 State Route 689
Meigs County
Albany, Ohio 45710
United States of America
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