[Elecraft] my KPA1500 and 160M

[Steve Hall]

Sounds like the KPA1500 is seeing more SWR than it likes.  My K3 is able to
match antennas faster and better than my KAT500.
I have had a number of antennas very similar to yours and spent many hours
experimenting with feedline length. The length of the open like has a
direct effect on the antenna system impedance.  Try varying your open line
length about 10 feet and with an antenna analyser measure the difference in
SWR curves before and after.  Additionally I find a 1:1 current balun
provides a better match than a 4:1.