In a message dated 7/17/2006 8:46:54 A.M. Eastern Standard Time,
cherokeehillfarm@earthlink.net writes:
The above data is from the AL 80B. I wonder how they manage to measure
their RF power output at 1 KW. There are others that seem to rate the output
from the modern tube much the same way. I never questioned my results because
they were more or less identical to the above data. Interesting to note the
10 second warm up time for this instant heating tube. I'll be these guys
have some spec sheets that I can't seem to obtain.
73 and Happy DXing,
Mike
W2AJI
Mike, Assuming in all cases only 100 watts is available for driving power,
one could drive an AL-80 to a KW output, but with the same 100 watts with an
SB-220 you will only see a max. of about 1300 watts. Now on the other hand,
if more power for driving was available >100 watts the Sb-220 will continue to
make power. No doubt the Sb-220 could get 1500 watts, but not with only 100
watts drive. Also, I have had MANY Eimac tubes and Chinese in my dozens of
Sb-220 I've owned and in some cases the Chinese tubes did better than Eimacs.
I also discovered that there is SOME truth to a "matched set" of tubes. I
encountered one extreme instance that really blew me away. I once mated a
pair of 3-500's in an SB-220, the power was way down, I substituted another
tube for one tube and the power went right up to snuff, so I thought I had one
bad tube and was lucky enough to pick it out the first time, Just for the heck
of it I put the other tube back in the amp (that I thought was not too good)
with the substituted tube and the power was right up to snuff. The
combination of the 2 tubes was just not right. I concluded at that point that
there
really was some validity to the "matched set" of tubes. Most likely in 99%
of the cases, you can mate any 2 tubes and get full power output, but there
just may be that 1% chance that 2 tubes wont work together. I think I
encountered that 1% chance one time. Lou
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