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
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