[AMPS] Finally - a real amp

[Rich Measures]

>
>It would seem to me that the operating parameters at the time of the failure
>do not explain the cause.  ip was only 150 and ip about 500.  Total key-down
>duration was no more than 20 seconds.  This does not compute.  Rich, I've
>seen you discuss VHF parasitics before.  What would be the recommendation to
>eliminate them?
>
Reduce VHF amplification by reducing VHF Q.  .  

>Doug -- W4DXV
>
>
>----- Original Message -----
>From: Rich Measures <measures@vc.net>
>To: Dick Green <dick.green@valley.net>; Doug Person <w4dxv@ibm.net>; amps
><amps@contesting.com>
>Sent: Friday, June 11, 1999 6:48 PM
>Subject: Re: [AMPS] Finally - a real amp
>
>
>
>
>
>>€  Semi-agreed.   However, under full drive, the grid/cathode potential
>>is typically110v-peak, or 78V-rms.  Grid dissipation is approx. 0.15a x
>>78v = 11.7w.  The rated grid-dissipation is 20w.
>>
>>What part do you agree with?
>>
>€   anode/plate current exceeded the manufacturer's limit.
>
>>Does full drive mean 65W?
>
>€  An approx. value.  Depends on anode supply potential.
>
>> I had the impression that the tube was being hit
>>with more drive than that (perhaps as much as the unfathomable 100W limit
>>stated in the manual.) That would make sense, because the tube would not
>>have loaded up normally at 65W if the plate choke was resonant on 17M,
>>tempting the operator to increase the drive further and twist the load knob
>>more. Wouldn't the excess drive increase the grid/cathode potential and
>>grid-dissipation, perhaps fatally?
>
>€ I have run a 3-500z  grid so hot it glowed, and no damage was done.
>With no gold plating to damage, the grid will apparently stand a lot of
>heat.  As I recall, Tom Rauch made a similar observation.
>>
>>It's interesting that the hole in the tube was facing the plate choke. Did
>>the choke's resonance on 17M have something to do with that?
>
>€   My guess is vhf did the melting.  .
>>
>-  later, Dick
>
>
>Rich...
>
>R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
>
>
>--
>FAQ on WWW:               http://www.contesting.com/ampfaq.html
>Submissions:              amps@contesting.com
>Administrative requests:  amps-REQUEST@contesting.com
>Problems:                 owner-amps@contesting.com
>Search:                   http://www.contesting.com/km9p/search.htm
>
>
>
>
>--
>FAQ on WWW:               http://www.contesting.com/ampfaq.html
>Submissions:              amps@contesting.com
>Administrative requests:  amps-REQUEST@contesting.com
>Problems:                 owner-amps@contesting.com
>Search:                   http://www.contesting.com/km9p/search.htm
>



Rich...

R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures  


--
FAQ on WWW:               http://www.contesting.com/ampfaq.html
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm