[Amps] Ameritron AL-811H-- Again

[R.Measures]

On Oct 1, 2005, at 6:35 PM, k7fm wrote:

> " This was c. the same time that I found out that General
> Electric Medical had cancelled a contract with Dick because he failed 
> to fix the problem of sudden 8877 failures in a MRI amplifier that he 
> was manufacturing for G. E."
>
> As I recall, the "parasitic" problem with the Alpha amps occurred at 
> exactly the same time that Eimac made a batch of bad ceramic tubes (in 
> particular, the 8877).

True, but according to Dick, the (damned) heat dam problem lasted about 
13 months, so it's an inadequate excuse.   When G. E. said there was a 
design problem, Dick should have listened.  Afterall, Fyler was a G. E. 
guy.   Also, Dick wasn't the only 8877 amplifier designer that ignored 
feedback-C, on Friday I tested an 8877 that came from a Dentron 
DTR-2000 and it exhibited gold-sputtering with the Joe Funderberg 
(W6IHA) test.

> At the same time you were analyzing the problem, Eimac changed the 
> construction of the tube.

Are you sure about this?

>  I am still amazed that your analysis of the parasitic problem in the 
> Alpha amps resulted in reduced problems for Alpha owners, even though 
> Alpha did not implement your ideas.

My ideas and analysis did not result in reduced problems for owners, 
reducing the VHF-Q of the suppressors used in Alphas resulted in 
reduced problems because less VHF-Q means less Rp, and that means less 
VHF amplification.

The puzzle here is why do some people still believe that it okay for a 
dampening device to have high Q?  This is like selecting a 
shock-absorber for an automobile that is very springy and lively.

cheers, Colin
>
> Colin  K7FM
>
>

Richard L. Measures, AG6K, 805.386.3734.  www.somis.org