>Greetings to the Group,
> I've just come into possession of an Eimac 4-1000A,
>glass chimney,
>and matching socket and am looking for a proven HF amp design to press
>them into service. If anyone knows of any good designs in past ARRL
>handbooks etc. PLS let me know. I'd be happy to pay duplication costs if
>the designs are viable.
>
Hi Steve,
As someone who is fighting this tube right now in an amp design, I would
say that if this is your first HF PA design, it's not going to be easy.
I didn't believe others about this at first, but the 4-1000A has some
very pesky resonances that tend to make it unstable especially on the
higher bands like 10 meters. It also needs very high voltage to get
adequate gain and lots of drive. Lots of guys use 5 to 6 KV. At that
voltage you get around 12 dB of gain. Lower voltages give somewhere
around 10 dB of gain. Lots of guys that have them (including myself) use
the bigger rigs like the FT-1000 that can put out 200 watts.
On the bright side it's an extremely rugged tube and can take a lot of
abuse. It's also kinda cool to see those plates glow bright orange! But
it likes lotsa cooling.
Tubes are available on the used market for about $100 each.
If you send me your address, I can send you a couple of articles that I
have on designs. This was a popular tube, but it's amazing how few
articles there are about it.
I am in the process of rebuilding my amp right now and correcting the
original designers sins. Keep watching for my updates!
73,
Jon
KE9NA
--------------------------------------------------------------------------
Jon Ogden
jono@enteract.com
www.qsl.net/ke9na
"A life lived in fear is a life half lived."
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