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Technical Topics => The RF Workbench => Topic started by: RedMercuryLabs on December 12, 2013, 0501 UTC

Title: So...what can a person do with 2 or 4: WL23791/TH150
Post by: RedMercuryLabs on December 12, 2013, 0501 UTC
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
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: redhat on December 12, 2013, 1059 UTC
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
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: RedMercuryLabs on December 14, 2013, 1612 UTC
(https://31.media.tumblr.com/4f2ee53d8523a8a4f06185ac4da44319/tumblr_mxt0qrdvDY1sax1lpo2_1280.jpg)
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: redhat on December 14, 2013, 2324 UTC
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
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: RedMercuryLabs on December 16, 2013, 0226 UTC
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...???
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: redhat on December 16, 2013, 0538 UTC
Either high power audio (read: Modulator :) ) or perhaps MW Finals.  Lacking published specs, we can only guess.

+-RH
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: cmradio on December 17, 2013, 1258 UTC
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!
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: RedMercuryLabs on December 18, 2013, 0243 UTC
Well well well.....maybe, just maybe it'll work.  Voltage is irrelevant next to the power of the force...
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: redhat on December 19, 2013, 0209 UTC
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
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: RedMercuryLabs on December 19, 2013, 0424 UTC
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.
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: cmradio on December 19, 2013, 1208 UTC
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!
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: redhat on December 19, 2013, 1827 UTC
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
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: Pigmeat on December 21, 2013, 1446 UTC
Why did you swipe Al Fansome's glow in the dark beanies, RM?
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: RedMercuryLabs on December 21, 2013, 1638 UTC
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 :)
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: ka1iic on December 23, 2013, 2344 UTC
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
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: RedMercuryLabs on December 24, 2013, 1746 UTC
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.

Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: ka1iic on January 17, 2014, 2041 UTC
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
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: RedMercuryLabs on January 21, 2014, 0609 UTC
 :P
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: redhat on January 21, 2014, 1247 UTC
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
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: ka1iic on January 21, 2014, 1924 UTC
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
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: redhat on January 22, 2014, 0911 UTC
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
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: ka1iic on January 22, 2014, 2304 UTC
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
 
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: redhat on January 24, 2014, 0131 UTC
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
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: ka1iic on January 29, 2014, 1807 UTC
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
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: Evodoc on April 09, 2019, 1709 UTC
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?
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: flexoman61 on April 09, 2019, 2145 UTC
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.
Title: Re: So...what can a person do with 2 or 4: WL23791/TH150
Post by: Evodoc on April 09, 2019, 2358 UTC
All those links are dead. He hasn't posted since 2014