On Fri, 10 Oct 2003 11:07:53 -0700, Jack Twilley
wrote:

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I recently sat down and calibrated my antenna, going through the bands
and recording the antenna tuner settings required to reach 1:1 on all
the bands my rig can run.

I'm thinking about another calibration I'd like to perform with the
tuner bypassed, trying to determine where on the bands I can use the
antenna without a tuner and still be within a reasonable SWR range.

I am hoping to preserve the lifetime of my tubes and maximize the
power available to me.

My question is: what is an acceptable SWR range? I know that 1:1 is a
desirable SWR, but when does SWR become undesirable to the point that
it shortens the lives of my tubes?

I am using a Kenwood TS-520 and an MFJ Versa Tuner II.

Jack.

Jack,

The 520 has a pi-network output. When properly adjusted, the pin-net
work will match the finals to the load. So if you are able to adjust
your plate and loading controls to the recommended grid and plate
current values everything will be just fine reguardless of the SWR.
Now if your SWR is so high as the 520 will not load properly then you
should think of bringing the tuner on line. Otherwise just leave it in
the by-pass position. Nothing is gained using the tuner if it isn't
needed.

73
Danny, K6MHE