Carl,
Your nasty index is rising, but there is one good technical point
hidden inside:
> Maybe in your version of reality but not in the world the rest of us
> inhabit.
#One.
> As hams we are not striving for some Nirvana level of perfection nor
> interested in a constant barrage of bull.
#Two
> Follow the classic articles and you wont go wrong. Follow the crap and
> you will wind up with a Mississippi Nightmare....or worse.
#Three .... and then a technical point
> Tom makes a few very good points but since the average ham has no access
> to the lab test equipment it is mostly moot.
Anyone owning a GDO, a simple common antenna analyzer, or a
transceiver and a low power SWR meter, and a few capacitors could
measure the inductance with great precision. Most Hams own
transceivers with some sort of SWR meter, and Silver Micas are cheap.
I hardly think any of that is "lab equipment".
>A reasonable error in the L
> will make very little difference in reality. As Tom has mentioned
> recently, a Q of 8 or 12, etc is no big deal.
another technical point...that's two
That's right, IF 8 or 12 is high enough to match the load and source
Z.
If the goal is getting close to what you want, it would be MUCH
better to calculate the values of caps. If you know that, by leaving
the tube, choke and stuff disconnected, and putting a small silver
mica from the tube end of the tank to the chassis and another one at
the loading C location instead of the loading C, you can do the
whole tank without ever having the tube filament on!!
The tank is terminated at the tube end by a small carbon or film
resistor, of the same resistance as the estimated tube operating
impedance.
Then the tank can be driven from the load end with a cheapo antenna
analyzer (or a transceiver and the inductor trimmed to perfect size,
with all sheet metal and covers in place, starting from the lowest
band and working up. Safe, fast, cheap, correct, accurate, and easy.
Or you could use the method requiring testing the tank with power
on, AFTER everything is soldered in place.
>If your variable C cant
> handle that much of a fudge factor then YOU have a problem that needs
> correcting.
# Four.
> A select few have strived to put amp design into an arena reserved for
> the self annointed gods.
#Five
> And learn to seperate the chaff from the chiff...or is it the other way
> around?
#Six.
In the middle of all the unnecessary nastiness, there was still two
areas where something can be learned. Nastindex of 6 over 2...or
three. ;-)
73 Tom
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