In a message dated 1/20/2007 10:17:50 AM Eastern Standard Time,
rstealey@hotmail.com writes:
I'll tell you guys an interesting little story about 6 meter amps that is
relevant to this discussion.
A few years ago a friend came to me for help with getting an amplifier
working on 6 meters.
He figured (rightly so) that a cost-effective and time-effective way to go
was to convert an
SB-220 that he had on hand. He had redone the tank coil, and substituted
new pi net caps,
but was only getting about 400 watts out. I think the original bandswitch
was still
in the circuit.
I talked to my friend Lou W1QJ (appropriately named "goodguyham") for
suggestions since I knew
he had a lot of experience with 6 m amps. Lou gave me a lot of advice for
such a conversion but said rather than me inventing the wheel all over again
to bring the amp up to his shop. To make a long story short in 2 hours in
Lou's shop we had new parasitic chokes installed by Lou, and a more
efficeint tuning cap installed, and a few other secret touches that Lou knew
about because of his experience.
We went home at 11 pm that night with a single band 6 meter amp putting out
about 900 watts, COMPLETELY stable. I mean more stable than that amp is on
20 meters. It is still working
perfectly 5 years later.
Now, if someone was homebrewing a new 6 m amp would 3-500s be the best
choice of a tube?
Probably not. But if you had an SB-220 and wanted a kw out on 6 meters,
there is no choice
in the matter. And let's not forget, "A watt is a watt." And a kw from an
8877 is the same on the air as a kw from an SB-220.
And if Lou offered me a tube better than an 8877, I wouldn't hesitate for
one second to
buy it from him. He is the most honest and generous ham I ever met, and one
of the most
competent homebrewers I know. Not only that he goes to Dayton every year -
He's a DOGGY!
(a member of "The Dayton Organized Group Gathering Yearly")
Rick K2XT
_________________________________________________________________
Gentlemen, I rest my case. Rick, it was a pleasure to help out your friend
and meeting another fellow ham.
I am sure he'll be in the contest with that amp this weekend. By the way, I
sold one of my converted SB-220 amps to K1JT. I tink he used it to develop
his new WSJT protocol. Another user of mine tells me he uses his on WSJT all
the time on 6 meters. GA-DAY....Lou
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