[Elecraft] KAT3 use questions

[Stan Gibbs]

I just finished building a K3 (#4181) and have a question about using the
KAT3.
When I hit the ATU button with the KAT3 enabled, it does its thing for a
second or two and then flashes a SWR value on the display as expected.  I
want to operate on 80m with a VERY limited choice of antennas.

My questions  are:
1) If the displayed SWR is, say, 4.1:1, does that tell me that the ATU
successfully matched the load and that I can operate the radio without fear
of damage?
2) What does the display indicate when it cannot achieve a reasonable match
and I should not operate the radio?

Thanks for any info on this.

73, Stan, KR7C