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
To: <amps@contesting.com>
>Date: Tue, 4 Mar 2003 07:47:55 -0800
>From: rlm <2@vc.net>
>To: "Tom Rauch" <w8ji@contesting.com>, " AMPS" <amps@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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