Hi Ian
It’s also good insurance against a blown PA as each deployment will have different characteristics and and EFHW needs a matching arangment to present a low impedance to the TX. When testing in the garden it was windy and even the slight gust of wind was altering the vswr a bit. It’s a compromise but works and works simply. I’m not a perfectionist but just interested in a solution that works for me and hence didn’t tune the resonant lengthen to closely as it may be different next time I put it up. It was low enough 20m 1.2 to 1, 30m 1.5 to 1 and 40m 1.7 to 1. Not worried about that but could do a bit to get 40 down playing with the length I suppose. There again I could get it it matched better in the garden and find it worse in the field. Theoretically the lengths should be about right and the tuner compensates for field variances.