[Amps] vapor phase cooling and old discussion revived - rambles TSPA

[John T. M. Lyles]

Hi

I have been dealing 'mostly' with water and vapor-phase cooled tubes 
since I left FM broadcast transmitter design 22 yrs ago. But I don't 
consider myself in the same league of experts as those ham/commercial 
amplifier designers/manufactures and tube manufacturers. My specialty 
(or my favorite work) is larger amplifiers, but since doing 88-108 
MHz cavity circuits and designs > 22 years ago, I mainly build 
onesy-twosey quantities anymore, very specialized applications. 
Still, as I have said many times, the technology usually scales 
rather nicely from big to small, so whatever works at 20+ kV usually 
works at <5 kV too, just not as critical usually. So take what I said 
with a grain of salt, as I am dealing with what we term ultrapure 
water (DI) and perhaps that is too expensive for a Stanley Steamer.

Dick's summary was good, I forgot about that. I think it comes with 
age, the memory and going around in circles again.....I am repeating 
myself too.

I wonder what became of Jon Ogden, KE9NA. I remember he was quite 
active here 8 years ago. Wow,time sure flies when you are having fun.

Something I forgot to ever mention here, I have heard feedback in the 
past 4 years from some of the tube manufacturers, that they even read 
our postings sometimes on Amps....And I don't mean just Eimac. As you 
know, it takes some effort to try and reply or post a query here, so 
some just troll and watch, without actively participating. I talk to 
some of them regularly with my work, so I know they do pay attention 
to reasonably technical discussions. When it gets into name-calling 
and pointing out whose totally wrong, it gets tiring for all.

I have never stopped reading Amps, although i get too busy to spend a 
few minutes and chime in sometimes. This stuff is in my blood, as 
many of you probably feel it too. We are a dying breed, however. The 
new generation of wireless punks and punkettes aren't doing as much 
in the way of device matching, selecting chokes, even picking power 
devices, as most of the PCS and Cellular and Bluetooth and WIMAX and 
so forth, are packaged devices, 50 ohms in and out, select a gain and 
noise figure and there you are. And integration of all this plus the 
digital processing has made it even more difficult for RF engineers 
and techs to do device and sometimes even module design.

I was showing a young Tech here yesterday how to fixture and measure 
and RF choke with an imedance meter to optimize its design for a 
single frequency RF network, as he always thought you just called 
Newark Electronics and ordered a stock choke, or worse yet, stuck a 
few ferrite beads over the wire.

I do enjoy reading about and absorbing info on the latest class E, 
Doherty, EER, new transistors for higher GBW, etc. QEX, some of the 
trade magazines, and this forum continue to ROCK.

73
John
K5PRO
New Mexico





>Paul Christensen wrote:
>>I almost forgot that this topic was covered by Dick Ehrhorn here on the
>>AMPS reflector nearly a decade ago.  Here's his insight on vapor
>>cooling and he even credits John Lyles in the middle:
>>
>  >http://lists.contesting.com/_amps/1998-08/msg00030.html
>>
>
>Newer readers may not be aware that, about a decade ago, people like
>Dick  Ehrhorn, John Brosnahan, John Lyles and various Eimac employees
>were regular contributors to AMPS. Their expertise and specific product
>knowledge are sorely missed.
>
>Welcome back to John - now, how about the others? If anyone is still in
>contact, please think about inviting them back.
>
>73 from Ian GM3SEK