W3RSW
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Rick & "Roosevelt"
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« on: July 16, 2008, 04:30:10 PM » |
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Isn't this a cool tube or what? Trade in your ol' 813's. Should be good for easy 200 watts dissapation in AM service. http://qro-parts.com/product_info.php?products_id=82Wonder how long they'll be available. The claimed service life is phenominal. |
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RICK *W3RSW*
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W1AEX
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Apache Labs SDR
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« Reply #1 on: July 16, 2008, 04:45:08 PM » |
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Heh, I like how it has a clamp around it so that it can't leap out of its socket.
Rob W1AEX
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One thing I'm certain of is that there is too much certainty in the world.
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W3RSW
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Rick & "Roosevelt"
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« Reply #2 on: July 16, 2008, 05:44:22 PM » |
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yeah, when your flyin' a Mig 29 you need all the 'g' proofing you can get  |
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RICK *W3RSW*
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k4kyv
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Don
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« Reply #3 on: July 17, 2008, 12:52:18 AM » |
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Looks like a Russian version of the old Western Electric 701-A tetrode. It was sort of a 304TL with a screen grid.
I wonder if that company will still be around in 25 years to make good their guarantee.
It might be a good tube.
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Don, K4KYV AMI#5 Licensed since 1959 and not happy to be back on AM... Never got off AM in the first place.- - - This message was typed using the DVORAK keyboard layout. http://www.mwbrooks.com/dvorak |
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W3RSW
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Rick & "Roosevelt"
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« Reply #4 on: July 17, 2008, 03:18:47 PM » |
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When I first saw it I thought it was a compactron! - until I saw the scale. Jeeze, it's a fat bottle, over 3" dia. and over 5" long. At $110 each I'm tempted to buy a couple. - Maybe a pair modulated by a pair and would you get a load of those internal plate 'fins?' From the broken Eng. literature I guess those internal fins are supposed to 'channel' electrons. Sort of like Eimac 8877's focused beams where the grid is aligned precisely but at the plate?
Also their 40uf/5kv cap. looks very stout.
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RICK *W3RSW*
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k4kyv
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Don
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« Reply #5 on: July 17, 2008, 10:00:50 PM » |
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I'd say the external fins on the plate are for heat dissipation purposes. Like the heat radiating fins on the older versions of Eimac triodes (304TL, 100TH, 250TH, 450TL, etc.)
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Don, K4KYV AMI#5 Licensed since 1959 and not happy to be back on AM... Never got off AM in the first place.- - - This message was typed using the DVORAK keyboard layout. http://www.mwbrooks.com/dvorak |
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W3RSW
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Rick & "Roosevelt"
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« Reply #6 on: July 17, 2008, 10:31:13 PM » |
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oh yeah, definitely what the external fins are, but look inside the plate in the one three-quarter view if you haven't already. You can see myriads of smaller fins pointing radially inwards from the main plate cylinder.
Almost hairy.
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RICK *W3RSW*
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w4bfs
W4 Beans For Supper
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more inpoot often yields more outpoot
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« Reply #7 on: July 18, 2008, 07:47:45 AM » |
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could the internal fins be some sort of secondary emission buster?
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Beefus
O would some power the gift give us
to see ourselves as others see us.
It would from many blunders free us. Robert Burns
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WBear2GCR
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Brrrr- it's cold in the shack! Fire up the BIG RIG
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« Reply #8 on: July 18, 2008, 07:23:22 PM » |
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Don, don't think it's a guarantee... just typical of the tube?? My reaction to the image when I looked at it last night was that the grids are not wound like the typical tube. They look like they are formed out of a solid bit of metal... sort of like the internals of a ceramic tube. That would account for their ability to handle the G forces. ...wonder what they did for the heater? 1/8" wide flat nichrome strips? probably very few failures due to shipping!  I like it. Wonder how it would do slammed in place of the typical pair of 6146s? Maybe not enough B+ to make it sing... but a candidate for modulator service?? The GU70 (was that it?) looks like an 845 on steroids... The Ruskies make some nice toobes! _-_-bear |
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Opcom
Patrick J. / KD5OEI
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« Reply #9 on: July 18, 2008, 11:24:27 PM » |
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I wonder what that socket is made of. Nice for the price. It's indirectly heated, I like that for ruggedness.
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Radio Candelstein - Flagship Station of the NRK Radio Network.
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WBear2GCR
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Brrrr- it's cold in the shack! Fire up the BIG RIG
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« Reply #10 on: July 20, 2008, 06:41:15 PM » |
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Compare - as seen on the back cover of the April 1958 QST: The RCA-7094!
Looks similar at least in concept.
500 watts CW, 1200vdc, AM phone.
_-_-bear
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KM1H
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« Reply #11 on: July 26, 2008, 07:52:48 PM » |
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It might just retrofit into a SB-220 once the Chinese decide to stop making the 3-500. Drop the screen from the HV (with some safety circuitry) and change the RF Power meter position to read screen current, the best way to tune a tetrode. The new filament xfmr can do double or triple duty to develop bias as well as relay voltage. The SB-220 fan will keep it happy. With enough reserve emission it may be very linear. Hmmmmm Carl KM1H |
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WBear2GCR
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Brrrr- it's cold in the shack! Fire up the BIG RIG
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« Reply #12 on: July 29, 2008, 06:13:04 PM » |
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Think it wants a lower B+ than the 3-500 by quite a bit...?
_-_-
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KM1H
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« Reply #13 on: July 29, 2008, 07:35:35 PM » |
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In a SB-220??
WHY??
Carl
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W3RSW
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Rick & "Roosevelt"
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« Reply #14 on: July 31, 2008, 11:18:45 AM » |
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It just dawned on me, this tube is probably rated to 50,000 ft. altitude too; should match one of my surplus transformers. And as an additional added attraction, it looks rugged enough to make it through UPS delivery. ....now where did I put those 15E's?... so cool, some of this old USAF stuff. Hey, probably USAAF for 15E's. |
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RICK *W3RSW*
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Opcom
Patrick J. / KD5OEI
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« Reply #15 on: August 02, 2008, 05:27:15 PM » |
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you have 15E's as well? Gor any 15R's to go with them?
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Radio Candelstein - Flagship Station of the NRK Radio Network.
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W3RSW
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Rick & "Roosevelt"
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« Reply #16 on: August 03, 2008, 01:55:20 PM » |
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no, wish I did,
the E's are brand new/(old surplus) but way back in my career of js hamdom I wanted to see them light up so hooked up a 5v fil. xfor to them. Glowed pretty and no wear at all what with a volt less than nominal. But the darn red paint logos turned from bright red to tannish red.
Didn't hurt a damn thing emission wise, but oh well....
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RICK *W3RSW*
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