Jim wrote:
>
> Its been kinda "dry" here lately................ Lets have a new
> discussion...................
>
> I am looking at the new 2000 ARRL Handbook. There is an amplifier
> construction project in chapter 13. The amp is built around a
> Svetlana 4CX1600B tube. I have been doing some research on the article and
> have found MULTIPLE errors.
>
> What I have noticed so far is that the part numbers on the toroids for some
> of the tank coils are incorrect.
> (L2.... 5 turns on 2 T-225-8 cores. Amidon does not make a T-225-8 core.
> L3.....6 groups of 3 each etc on three T-225-28 cores. Again, same problem.)
>
> L1 is described as having 6 turns 1 1/4" inside diameter. And 4 1/2 turns
> with a 1 3/4" inside diameter. Looking at the picture in the handbook of
> said amplifier (and at the inside view of the Commander HF-2500........the 6
> turn coil is the large diameter one! and the 4 1/2 turn coil is the small
> diameter coil !!
>
> There is also an error on the schematic on the band switch. It shows a
> separate tap for 12 meters. The text in the parts list says there in 1 tap
> for both 10 & 12 meters. The schematic also shows that L2 is the 20 meter
> inductor. But the parts list shows that "all of L1 is used for 20 meters !
>
> In looking at the pictures of the Command Technologies amplifiers on their
> web page, the parts that are pictured and described in the Handbook are
> from a HF-2500E and not from an HF-2500 as the text in the Handbook elates
> to.
>
> I have also heard that RF Parts had about 5-6 of the 4CX1600B tubes in
> stock.......and does not know when more will be available. Are they that
> hard to come by ????
>
> I wonder who has tried to build this project ?
>
> Any thoughts ???
>
> "Things that make you go HHHMMMMMMM....."
>
> 73
>
> Jim W7RY
>
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Jim,
I thought you might be interested... There is a russian tube GS-23B that
is the same as a 4CX1600U. I can tell you where to get a few (from a
ham in Japan) and these russian tubes from him are really inexpensive.
I'm going to email him to get a price. I have already got two brand
new GI6B's from him for only 15.00 a piece w/ shipping! Nice tube.
Anyway, might help with this project!
Phil W2GE
--
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