The AM Forum
March 28, 2024, 04:25:06 PM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: 1 [2]   Go Down
  Print  
Author Topic: Think your final tube is big enough?  (Read 21211 times)
0 Members and 1 Guest are viewing this topic.
John K5PRO
Member

Offline Offline

Posts: 1033



« Reply #25 on: March 24, 2012, 04:50:00 PM »

The 6949 was a mighty big tube, 40 inches overall length. but so was the UV862. The new TH628 is replacing RCA 7835 'super power' GG triodes. Compact size is important for VHF of course. 6949 runs 20kV at 50 Amps at 10 MHz. TH628 runs 28 kV at 150 amps, at 200 MHz... Only other tube that's close (and close in power only, not in max frequency) is the 4CM2500KG from Eimac. Its a brute also.

My 851 will have to do for aesthetic appeal here! See my tee shirt in the photo of the TH628 diacrode...
Logged
KM1H
Contributing
Member
*
Offline Offline

Posts: 3519



« Reply #26 on: March 24, 2012, 05:46:58 PM »

The 862 has to be right up there in vintage glass at 60" tall including water jacket. There were 12 in the final of the WLW 500KW rig.
Another 8 were in the modulator.

http://tubedata.tigahost.com/tubedata/sheets/049/8/862A.pdf
Logged
Opcom
Patrick J. / KD5OEI
Contributing
Member
*
Offline Offline

Posts: 8308



WWW
« Reply #27 on: March 24, 2012, 07:37:41 PM »

I guess the biggest one around here is an ML-892. Being water cooled it will likely never be used. looks pretty.
Logged

Radio Candelstein - Flagship Station of the NRK Radio Network.
WA1GFZ
Member

Offline Offline

Posts: 11152



« Reply #28 on: March 25, 2012, 08:42:46 PM »

OK John, You win.
You have the best RF toys!
Logged
The Slab Bacon
Member

Offline Offline

Posts: 3934



« Reply #29 on: March 25, 2012, 08:58:20 PM »

OK John, You win.
You have the best RF toys!

Dats right,
               who needs class-E when you got tubes like that to play with  Grin  Grin
Logged

"No is not an answer and failure is not an option!"
KM1H
Contributing
Member
*
Offline Offline

Posts: 3519



« Reply #30 on: March 25, 2012, 09:11:36 PM »

Im in QRP category!

The largest glass is a pair of 6C21's which is replacing the 250TH's

The largest ceramic/metal is a YC-156 for a future amp

The most power is a 3CW20000A7  its virtually new and Im just dreaming so far. Complete with socket, filament transformer and filament blower and mounted on a ready to use plate. Came from a local tech college where it was used as a demo, never had HV applied.


* 3CW20000A7-1.jpg (68.61 KB, 600x450 - viewed 1718 times.)
Logged
Opcom
Patrick J. / KD5OEI
Contributing
Member
*
Offline Offline

Posts: 8308



WWW
« Reply #31 on: March 25, 2012, 09:54:20 PM »

So John, when you upgrade those equipments.. and throw away the old tubes... I'm guessing they don't throw out much. Do they still auction off stuff and it goes to the Black Hole or is the BH not buying much any more?
Logged

Radio Candelstein - Flagship Station of the NRK Radio Network.
David, K3TUE
Per-spiring AM'er
Contributing
Member
*
Offline Offline

Posts: 394



« Reply #32 on: March 25, 2012, 11:09:05 PM »

Is this for real?



Found here http://www.jacmusic.com/nos/rectifiers.html
Logged

David, K3TUE
W7TFO
WTF-OVER in 7 land Dennis
Contributing
Member
*
Offline Offline

Posts: 2521


IN A TRIODE NO ONE CAN HEAR YOUR SCREEN


WWW
« Reply #33 on: March 26, 2012, 12:10:34 AM »

Sho nuf.  That is from the old Eimac site.

73DG
Logged

Just pacing the Farady cage...
John K5PRO
Member

Offline Offline

Posts: 1033



« Reply #34 on: March 26, 2012, 01:26:37 AM »

The old Eimac photo is their HF test set for the 8974, which was called the X2159 at the time. Ads for this tube used to be on the inside back cover of QST. Most of those tubes were used in big Continental MW transmitters in the middle east, 1 MW carrier power. We used 8 of them in 1 MW pulsed amplifiers at 50 MHz, those have since been mothballed. I grabbed one tube, just for trophy, in storage now. Its a very big tube, but not good for VHF use. The 8973 is a shorter fat tube, that had wire grids. It morphed into the X2142, then X2174 (I think) which led to the 4CM2500KG (pyrolytic graphite grids). These tubes were optimized for CW and fusion heating power.

Patrick, about 10 years ago one of the 8974s did appear in the crate at the Black Hole. I was surprised, ol' Ed wanted $500 for it. I don't know who bought the tube but its gone. Nowadays, most electronics goes to Bentley's auctions every month in Albuquerque. As for the 7835 triodes and their cavity amplifiers, likely will transfer those plus their RCA 4616 tetrode drivers to 2 other Nat Labs where they continue to use the same amplifiers in proton injector linacs.
Logged
John K5PRO
Member

Offline Offline

Posts: 1033



« Reply #35 on: March 26, 2012, 01:29:26 AM »

That 3CW20,000A7 looks like a dandy final amp device. When i worked in RF heating industry in the late 1980s, we used a lot of 3CW30,000H3's at 27 MHz.
They would have been pretty bad for linear amplifiers, needing a lot of grid drive power.









Logged
The Slab Bacon
Member

Offline Offline

Posts: 3934



« Reply #36 on: March 26, 2012, 09:12:22 AM »

That 3CW20,000A7 looks like a dandy final amp device. When i worked in RF heating industry in the late 1980s, we used a lot of 3CW30,000H3's at 27 MHz.
They would have been pretty bad for linear amplifiers, needing a lot of grid drive power.


Yea, but the chicken banders would have figgered out some quick and dirty way of doing it!

"Ignorance is bliss"   Roll Eyes  Grin  Grin
Logged

"No is not an answer and failure is not an option!"
John K5PRO
Member

Offline Offline

Posts: 1033



« Reply #37 on: March 26, 2012, 08:43:22 PM »

Here's the other photo that Eimac used in their 1970s X2159 advertisement in QST. It was more of a capabilities showing, than an endorsement for hams to buy this tube! The late George Badger was likely behind this great advertising. I showed him my 851 avatar 10 years ago at an NAB conference, and he
glowed and chuckled.

Also, here is the placard that was stapled to the side of the crate they shipped a 4CW250,000B in. 


* Most powerful tube sign.jpg (156.25 KB, 576x374 - viewed 641 times.)

* X2159 Baby.jpg (100.63 KB, 507x624 - viewed 774 times.)
Logged
Pages: 1 [2]   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone © 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.039 seconds with 18 queries.