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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