[Amps] 8877s, ETO and the General Electric Contract

rlm 2 at vc.net
Tue Mar 4 18:16:31 EST 2003



>No cramping here, I don't think Bert has any either.
>
** Good 

>No, i have a better idea, why don't you filter the rest of us out.
>
**  I filter spam. 

>Fight on.
>
>Dale J.
>
>
>
>>Filter out the Subject with your E-mailer app., and the cramping will go
>>away. 
>>
>>>I agree with you Dale. Let's move on to something more interesting.
>>>
>>>Bert A.
>>>
>>>
>>>-----Original Message-----
>>>From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com]On
>>>Behalf Of dj2001 at mn.rr.com
>>>Sent: Tuesday, March 04, 2003 8:51 AM
>>>To: amps at contesting.com
>>>Subject: Fwd: Re: [Amps] 8877s, ETO and the General Electric Contract
>>>
>>>
>>>
>>>This reminds me of a bloody barroom brawl.  It's getting kind of ugly
>>>sorry to say and I'm not learning anything useful about amplifiers.
>>>
>>>Dale J.
>>>
>>>
>>>
>>>
>>>
>>>>Subject: Re: [Amps] 8877s, ETO and the General Electric Contract
>>>>Date: Tue, 4 Mar 2003 07:47:55 -0800
>>>>From: rlm <2 at vc.net>
>>>>To: "Tom Rauch" <w8ji at contesting.com>, " AMPS" <amps at contesting.com>
>>>>X-BeenThere: amps at contesting.com
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>>>>
>>>>
>>>>
>>>>>   I started to have this problem in 10th grade and the problem isn't
>>>going
>>>>>   away.
>>>>>
>>>>>The problem is rooted in false claims, poor technical advice, poor circuit
>>>>>behavior descriptions, and general misinformation. Unless the correct
>>>>>information gets out, the problem will continue. We should concentrate
>>>more
>>>>>on technical issues, and less on what we "imagine".
>>>>>
>>>>>   ** Interesting, Dave.   I apparently assumed wrongly.  My take on the
>>>>>   issue is that GE knew more about the 8877 failure problem in ETO
>>>>>   amplifiers than is assumed by some.   GE's awareness of the VHF
>>>parasite
>>>>>   problem goes back to 1935, when GE engineer G. W. Fyler wrote about the
>>>>>   problem in "Parasites in Transmitters" in the Sept. issue of the IRE
>>>>>   Journal.  //  The first Eimac technical data sheet on the 8877 was
>>>>>   published in 1970.  Eimac's W. B. Foote told me that the gold-migration
>>>>>   problem was discovered by the 8877 development team.  Thus, they must
>>>>>   have known about the gold-migration phenomenon at least 16-years before
>>>>>   Foote told me about it in February of 1986.
>>>>>
>>>>>Neither the Foote letter nor GE said anything of the sort.
>>>>
>>>>I have no idea what GE said to Dick E.
>>>>The Eimac Letter:
>>>>=======================
>>>>"VARIAN ElMAC, 301 Industrial Way
>>>>San Carlos California 94070 1 U.S.A. / Tel. (415) 592-1221 TWX 910
>>>>376-4893
>>>>February 18, 1986
>>>>
>>>>Mr. Richard L. Measures
>>>>6455 La Cumbre Road
>>>>Somis, CA 93066
>>>>
>>>>Subject: 2 pcs returned 8875 S/N G8AD-241 and F8VD-428J, for evaluation.
>>>>Reference: Your letter dated 21 January 1986; EIMAC RPA #SC-2303.
>>>>
>>>>Dear Richard:
>>>>
>>>>Your letter about parasitics is quite interesting, and it appears your
>>>>two tubes have had the same trouble. The emission was poor on test, and
>>>>consequently other test results looked bad. The tube engineer then cut
>>>>them both open for an internal examination.
>>  >>Both have been badly overheated internally, the apparent result of an
>>>>oscillation condition. The grid in these tubes is gold plated and if
>>>>overheated the gold vaporizes off, of course, and some of it inevitably
>>>>lands on the oxide cathode, and that poisons emission.
>>>>
>>>>Though your tubes are quite old (mid-1978 vintage) we will replace them
>>>>in the interest of good user relations. We will scrap the two you sent in
>>>>here, as we have to be sure they are out of circulation when we replace.
>>  >>Good luck in your continued operation.
>>>>
>>>>Sincerely, WILLIS B. FOOTE, Chief Specifications Engineer, Power Grid
>>>>Division."
>>>>------------------------------
>>>>**  I take this letter to say that gold apparently evaporates during an
>>>>oscillation condition.
>>>>>
>>>>>Back in the 30's, tubes had long thin leads.
>>>>
>>>>**  Some still do.  However, low L leads only move the problem higher
>>>>because the ability to oscillate also moves up.
>>>>
>>>>>Nearly every amplifier was
>>>>>operating at the upper frequency limit of construction, components, and
>>>>>wiring. Becuase the amplifiers were operated near the limits, having very
>>>>>poor tubes, wiring, and components by today's standards there was no
>>>>>effective way to stabilize the PA's.
>>>>>
>>>>** G.W. Fyler (and F. E. Handy) came up with a simple idea that proved to
>>>>be fairly handy -- i.e., "the plate or grid parasitic circuits should be
>>>>damped with resistance". (GWF. Sept.1935)
>>>>
>>>>>It was impossible, in the 30's, to get enough transfer from current in
>>>>>inductance to the dissipative resistance as the frequency of oscillation
>>>is
>>>>>approached because the operating frequency and instability frequency much
>>>>>closer than they are with devices even from the 40's and 50's.
>>>>>
>>>>** Say what ?
>>>>
>>>>>Because of poor layouts and poor components amplifers had to be
>>>gain-reduced
>>>>>even near the operating frequency.
>>>>>Only a fool would think that has some universal meaning in modern systems.
>>>>>It would be like insisting jet engines use gravity-fed fuel systems, which
>>>>>worked so well in the early days of aviation. Vastly different systems
>>>>>almost always require different solutions, when looking for the optimum.
>>>>>
>>>>>   The story I got was that GE was concerned with the tube failure rate.
>>>>>
>>>>>The story I heard was you applied for a job at a major amplifier
>>>>>manufacturer, and your application was rejected.
>>>>
>>>>**  I was a metrologist who also taught electronics. Amplifier building
>>>>was just a hobby that started when I was 15.
>>>>
>>>>>I was told since then, you
>>>>>have had a grudge against ETO and all manufacturers.
>>>>>
>>>>**  I didn't know anyone who got cremated in a Ford Pinto or Crown
>>>>Victoria rear-ender.
>>>>
>>>>>   plant.  When I mentioned the 150 figure on AMPS a couple of years
>>>later,
>>>>>   Dick said I was going insane.
>>>>>
>>>>>I know you say some things here that you attribute to me that I never
>>>said.
>>>>
>>>>**  Like the letter I received from a person who claimed to be Tom Rauch
>>>>which threatened to sue me and QST if my Rebuttal to the 9-94 QST was
>>>>ever published in QST?  If this person was an impostor, his timing was
>>>>uncanny since his letter arrived about a 10-days after I mailed a copy of
>>>>my Rebuttal to the real Tom Rauch.
>>>>
>>>>>I always wonder how often you do that in "technical" discussions. Why not
>>>>>leave all the personal stuff  about Dick
>>>>
>>>>**  Dick E. played the Insane Card and I said so.
>>>>
>>>>>and everyone out, and stick to
>>>>>honest facts?
>>>>
>>>>** Like when the smoke began to clear at the end the Grate Parasitics
>>>>Debate, when your faithful groupies were suggesting that I was probably
>>>>boinking the teenage girl who was filling suppressor retro-fit kit orders
>>>>?
>>>>>
>>>>Cheers, Tom
>>>>
>>>>-  R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K,
>>>>www.vcnet.com/measures.
>>>>end
>>>>
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>>>
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>>  >
>>>
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>>>
>>
>>
>>-  R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K,
>>www.vcnet.com/measures. 
>>end
>>
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>
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>


-  R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K, 
www.vcnet.com/measures.  
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