A TS-520 has vacuum tube output stages --
Vacuum tubes are very forgiving of SWR --- unlike solid states rigs.

I operated a TS-830S (tube outputs) with swr's well over 3:1 for years (no
tuner) and never had to change the finals.

Not desireable but in my case had no choice as I didn't have a tuner and the
SWR was high on one end of the band for my junior beam.

Caveat -- your tube life may vary !!!!!

--
73 From
"Cecil Moore" wrote in message
...
Jack Twilley wrote:
My question is: what is an acceptable SWR range?
I am using a Kenwood TS-520 and an MFJ Versa Tuner II.

Your transceiver manual should specify a maximum SWR.
For my IC-706, it is 3:1. I consider anything below
2:1 to be perfectly safe. That's about 11% reflected
power. Most modern transceivers are equipped with
foldback circuitry to protect the finals.
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73, Cecil, W5DXP