Posted on May 27, 2019
Two 40M Half Squares fed in a variable phasing configuration
Just for laughs – I decided to take that old “Mod Bob” idea that I had a few summers ago and see if that feed system might better apply to a true Bobtail Curtain – full size. It does seem to be the case. The above diagram would feed two half squares in the center, using the two Collins 180S-1 tuners in the “L Mode”:
Collins 180S-1 antenna tuners at KY6R . . .
Two Phased Half Squares with 90 degree phasing adds up to 2 dB over my DXE DV-40P system.
I checked the 180 degree phasing – and its the same as the DXE DV-40P. The cool thing is that I could phase this system using “variable phasing” – or phase angles in between 90 and 180 degrees – and sure, the pattern can get a bit weird – but it opens up the idea that with two tuners and 4 stepper motors (L and C on each leg, each fed against a ground rod) – I will have a lot more flexibility – PLUS – the ability to run this antenna on multiple bands – something the DXE-40_P can never do. Just retune each 180S-1 remotely.
The antenna can be used on 80M and 30M with decent patterns and gain. Its even decent on 160 …
OK – very soon – I will be re-purposing the three aluminum elements that I have – and will make this 140′ wide beast. It will require weed whacking and tree branch trimming – the perfect Summer project.
My neighbors 60′ cedar tree just snapped and fell this morning, reminding me of how temporary tree based antennas are. I’ll use three aluminum masts with a top wire connecting each.