--- In ham_amplifiers@..., R L Measures <r@...> wrote:
On Sep 24, 2006, at 5:05 AM, pentalab wrote:
--- In ham_amplifiers@..., R L Measures <r@...>
wrote:
### getter's [per Eimac and Svetlana] are ALWAYS
working... as long as the fil is lit. HV + drive are not
part of the overall gettering process.
Rich- If this is the case, why not use the tubes as they are being
gettered? This has always been the way that I have done it.
### Hey Rich....... if you blow up ur new rebuilt Svetlana
4CX-10,000J... don't come whining to me !
### All I was trying to get at was.... if 16 guys say to
use 48 hrs to getter a new/rebuilt tube.... and anything less is
gonna be a problem... cuz they have tried many diff time
frames... who am I to argue?
Rich-I have run into a number of amateur radio dudes who advise
something that sounds semi-plausible, but instead of being based
in science, it turns out to be an artifice for promoting his guru
status by giving the appearance of having esoteric knowledge.
### Well these dudes were very adamant about the 48 hour
gettering process. Forget the science.... real life practical
experience is what counts. The tube is good for 35,000 hrs
b4 a rebuild..... so what if u leave the filament on for 48
hrs... it can't do any harm. A few of these fellows have a
LOT of experience with those tubes....... Jerry at Economy
Electronics buys the entire production run of YC-243's from
Eimac each month [socketless 6000A7]. He told me the same
deal..... 48 hrs.... or u could easily experience trbl.
### Eimac tells me the YC-243's that come in to be rebuilt, none
have had a fried grid in em... that's just a side story.
## I don't have the time or patience to inadvertantly
destroy expensive new/rebuilt tubes.
Rich - I have probably never run filaments for more than a minute
before firing up a new 3-500Z or 8170.
### 3-500Z's need the anodes to show colour to getter em.....
so whether u run the new 3-500Z fil for just a minute or 48
hrs is irelevant.
### How many DOZENS of new 8170's have you fired up ???
### You gotta be very carefull here Rich. Anecdotal experience
with just one of anything is no subsitute with experience
with hundreds of the same thing. When a fellow who sells
literally hundreds of big metal triodes/tetrodes.... and has a lot
of experience with em sez 8 hrs is not enough to getter
em.. or XYZ will happen..and does,.... and to use 48 hrs min....
I tend to listen.
### when guys tell me 1/2" tubing tank coils run so bloody
hot on 10m, they require 100-200 cfm.... I tend to listen,,,and
not try an re-invent the wheel. [on 10m, you can easily be
dissipating 200w of heat... all of it into just a 2-3 turn
coil.... as opposed to 120 watts of heat on 20m..... and way
more turns on 20m to boot]. Actually 3/4" is better.... and
strap... laid flat... like a parasitic suppressor wound on a
globar is the best for a 10m tank coil. Strap will have RF
flowing down both sides.... where as tubing only conducts on the
outside. 1.5" wide strap works superb... eq to 1"
tubing... and minimal stray C between turns.
Jim VE7RF
