On Mon, 02 Aug 1999 12:37:15 -0400 Pete Smith <n4zr@contesting.com>
writes:
>
>From time to time we've seen posts about how the SB-220's input
>network is
>badly designed for 10 meters, and that results in lower output.
>
>Mine has a relatively high input SWR (ca. 1.8:1 on the part of 10
>meters
>I'm interested in) and suffers from low 10m. output (ca. 800 watts at
>best), but even when I use the built-in tuner on my transceiver to
>match
>the input perfectly, the output doesn't rise significantly. Why is
>this?
>Is there really no alternative to taking the amp apart to get at the
>input
>circuit and change component values?
There's some loss in the tuner in the 850, which at least partially
cancels any additional power out of the solid state PA.
I had the same problem with my SB-220s, and changed the input
to a parallel tuned ckt with a Radio Shack trimmer in parallel
with the Heath coil. Now 10m output is identical to the other
bands. SWR is 1, and the tuner is not required. If I run the tuner,
power is reduced quite a bit.
Dave Hachadorian, K6LL
San Diego, CA
K6LL@juno.com
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