Date: Wed, 6 Dec 2017 07:42:40 -0600
From: "Roy Koeppe" <royanjoy@ncn.net>
To: <amps@contesting.com>
Subject: Re: [Amps] Multi tube amp
<Seems to me there was also one in strays that use something like a dozen
1625?s on parallel...(etc.)?
<Yes that was my amp ? think it had 20 of them with a broad banded input and
output. I can?t locate the issue so far! Had a photo of it in Strays. I used
that amp for several years.
<73, Roy K6XK Iowa
## saw that in an old qst. The plate load Z was so low, it was 75 ohms....
no description on how u get rid of harmonics ! Me, I woulda used a plate
block cap, and no more,,, then stuff it
into the ant.
## On that galaxy 2000 amp, it used 10 x 6HF5 sweep tubes..and was a 80-10m
affair. 1 kv at 2A to provide the 2 kw input..and 1.2 kw output at the
time.
Plate load Z was less than 290 ohms. That would of course require VERY high
values of tune and load C.....and a real small coil. Plus aprx a whopping
20A
of circulating RF current through the coil + bandswitch. Their fix was
unique, they used a simple step up Z transformation. Stepped the plate load
Z up high enough,
such that... normal values of PI net could be used. Enter a plate load Z of
290 ohms into the GM3SEK Pi spreadsheet, and u will see the crazy high values
required for
both air variables...and the tiny values used for the coil. The PI-L is
no better.
Jim VE7RF
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