Tweaking the half sloper.

For several years now, I've been using half-slopers cut for the 40 and 30m bands off a common 1:1 balun feedpoint where the 'missing half of the antenna' is provided by my tower, which has a 12m LFA on top, in this case, acting as a capacity hat.  When I go onto 60m, I just add a disconnectable 5m length of wire to the 40m leg.

Foggy morning!  40m half-sloper in kevlar wire.

Whilst 40m was a very good match, needing no ATU tweak, the 30m leg was not as good as it should have been.  Because putting new antenna ideas up often happens during the boredom of the dark winter months, at least here, I guess I just stuck this leg up on a wet, windy night, found it a reasonable match, easily tweaked with a very small amount of ATU involvement, and just never perfected it.  I also don't really use 30m much, so there was no pressure to change things, either.

7MHz half-sloper: no need for adjustment there!

Anyhow, I decided I would have a look and try to improve the 30m leg this morning.  I had plenty of spare wire wrapped around the end nearest the ground, so it was easy to adjust things.  The wire was quite a bit too long, and there were a few small tree branches and leaves touching the wire, which would also tend to make things look longer.  

So I cut the tree growth first.  Still a bit too long.  Just unwrapped the wire, released the tensioner, and wrapped some more wire up to make it shorter.  After a quick check on the analyser, I could see the wire was now pretty much as good as it could be.

10MHz, after adjusting (in this case, for the WSPR and FT8 frequency areas).

Half slopers have proven very effective, if not the best possible antenna type here.  In particular, they have made it possible to keep working in all but the worst hurricane-force winds, and even then, it's the Yagi that forces the whole tower system to be lowered for protection.  Some say they are difficult to match, but that seems to only be true when a tower or other metal support acting as the missing half of the antenna has no Yagi or similar antenna as a capacity hat.