HFU HF Underground
Technical Topics => The RF Workbench => Topic started by: RedMercuryLabs on December 12, 2013, 0501 UTC
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I have been looking for a good way to utilize my newly acquired WL23791/TH150 tubes. Like I said on the air, I currently have 2 of these. They are new old stock. I can get 4 total.
Question: Do I make some sort of linear amp with just one, or 2 at a time? They may work like trash. Specs on these things is a little sparse.
Do I run 4 at a time? Oh my....questions questions...
Ideas? Schematics for a good SIMPLE build.
Our research is mostly biological here...these funny glass tubes are a beautiful distraction... :P
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Any possibility of a picture?
Specs say 10KW PEP output at 5.4 KW dissipation. Thats a fairly hefty tube for its day. You'll probably need a kilowatt to drive it to full ratings.
+-RH
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(https://31.media.tumblr.com/4f2ee53d8523a8a4f06185ac4da44319/tumblr_mxt0qrdvDY1sax1lpo2_1280.jpg)
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Richardson Electronics lists that as a dielectric heating tube. Anything with strap leads is usually low frequency, IE don't try and build an FM PA out of it. I can't vouch for its capabilities because I can't find any data on it either, but anything I've looked at that specifies something for power oscillator service probably isn't very linear. It would make one hell of a gheto blaster though :)
+-RH
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Burial at sea is not an option, just for their simple value in auctions. What the hell are folks using these for? I'm familiar with dielectric welding...but still...??? Romulian Disrupters are still very much outlawed...so what other use could there be...???
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Either high power audio (read: Modulator :) ) or perhaps MW Finals. Lacking published specs, we can only guess.
+-RH
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I can't vouch for its capabilities because I can't find any data on it either...
Try: http://www.datasheetarchive.com/WL23791%2FTH150-datasheet.html
Says it's good to 30MHz.
Gonna need 9V @ 60A (300A starting current) for the heater alone!
Peace!
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Well well well.....maybe, just maybe it'll work. Voltage is irrelevant next to the power of the force...
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It might be a good candidate for grounded grid service. That eliminates the need for neutralization, at the expense of lower power gain. Datasheet says not to exceed 115% carrier level, so your looking at an honest 10 KW PEP with probably 1K of drive. Software is available on the web for calculating tank values for the output network. You will need 7 KV @ over 1A for full ratings.
+-RH
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So...I'm trying to obtain the perfect transformer for this little project. Hmmm...maybe in the 220V flavor. I'm sure it will be a good third anchor for The Red Mercury herself.
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If you aren't going to push it to full input, that 3500VCT monster from Hammond might work for you. Run it FWB with a choke input filter and you won't have to derate it so badly.
Peace!
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You could (in true indie spirit) use microwave oven transformers. Locate two that are the same, and remove the shunts from them. There was a neat article all about it in QST recently.
+-RH
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Why did you swipe Al Fansome's glow in the dark beanies, RM?
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I had an "old" friend pass them down. I'm pretty excited about them. They are so beautiful, and feel and weigh about the same as a newborn baby. I have done everything but name them :)
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If you could get an 'poll pig' you might be able to use that as the plate voltage... got any inside contacts with your local power utility? You use it 'backwards' of course... 220vac to the tranny with High voltage coming out of the that end of the tranny... seen it done many times... a high current Variac on the 220ac line makes it variable to the plate side.
Man if you could get one of these in the RF stage and use 2 more as the modulating stage... you would have one hell of a set up... but what would you use as a modulation tranny...
Your best bet would be to run the tube as a Class B stage for AM... if that is where you are going...
73 Vince
ka1iic
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Vince -- That was where I was leaning. Something this beautiful and powerful deserves nothing more than amplitude modulation.
Poll pigs are available surplus...and would make a perfect reserve anchor. With the protruding electrodes, it would even dig into the mud.
I'm trying to find a good homebrew or even commercial schematic. I would hate to power this up, and have it launch off the deck :) Fireworks are fun, but this little baby probably has a ton of smoke to let out.
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Wellllll.... diagram ehhhh????
Check out Gates transmitters... RMI also comes to mind but in the mean time check out the diagrams here:
http://bama.edebris.com/manuals/
What would be great would to have the mod tranny AND the matching mod reactor to go with it... serious power calls for serious components... ;-)
Have fun... :-)
73
Vince KA1IIC
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:P
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Finding a modulation transformer at that power level won't be easy. I've contemplated similar arrangements with big tetrodes for carrier levels over 10KW, but for the previously mentioned difficulty, decided the best route would be a linear amplifier, rather than high level modulation.
+-RH
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Yep mod iron can be a MAJOR problem... but never fear... series modulation can and does work :-) quite effectively too... Just an idea from this 'old fart' heh
73
Vince
KA1IIC
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I'm not sure I would want to witness the initial startup of a series modulated 10KW AM rig. Sounds like a fire department affair.
+-RH
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errrr... I didn't say fire it up at 10kw <heh> but that would be something like henry yell are might try... complete with clip leads heeeheee...
heh
73
vince
ka1iic
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My point was that, series modulation does work, best at low power levels because of the inefficiency involved. If you were going to do high level PWM ala Harris's MW-5, et all, thats a different story. High level PWM does work very well, and even today's solid state MW and SW transmitters under 6KW use this principle. To my knowledge, the only domestic manufacturer of high level tube PWM transmitters is continental electronics. They have a 50KW "Solid state modulator" which is essentially 48 750V power supplies individually series modulated with PWM and wired in series to get 10KV average B+ for the final tube. The benefit; no modulator tubes, high efficiency, and lower operation costs. The custom plate transformer which rolls on railroad track by the way, must be a pricy one. Never mind the fiber optic drive system.
+-RH
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very true Redhat :-)
If it were myself... I'd go with low level modulation and use the big tubes as a class B amp... tune up would require a scope but that's no big deal... and a person can realize very decent audio quality using great care...
PWM is great, I've never done that but I have heard that keeping the pulse train out of the system needs a lot of filtering... I'm way too lazy for that gig <heh>
73 Vince
ka1iic
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I know this is a very old thread but does anyone know how to contact RedMercuryLabs to find out if he still has any of theses tubes?
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I know this is a very old thread but does anyone know how to contact RedMercuryLabs to find out if he still has any of theses tubes?
He has contact info under his icon.
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All those links are dead. He hasn't posted since 2014