[hertzian]

Testing was interesting, and I was encouraged that it followed the same overall setup as the horizontally-fed dipole(s).

The regular half-wave dipole works fine, although for my targets, I've got a lot of buildings in the way and I'm also down in a valley. So while I could hear them, they were just a bit weaker. I've GOT to get a receiver with a real S-meter. I'd love to live out in the clear or have a normal half-wave up on top of the house instead of the 3/4 low in the attic.

From the MFJ analyzer, I immediately got about 2:1 to 3:1 across the 118-136 band. This is without any trimming of the element or sliding the chokes around. Close enough for me for rx-only work - at least with my short runs of cable at VHF.

For the 3/4 wave element version, I used 75-ohm coax and got around a 1.5 - 2.5:1 swr across the band. (1/4 wave choked on coax) Again, close enough. Remove the chokes, and there's nothing but reactance. I'm using a 50 ohm device to 75 ohm cable, so reading will be off somewhat.

This made me laugh - when constructing another one, I had the receiver on, and only had the coax laying on the floor without the whip. Everything is nice and quiet. When I put the chokes on at the 1/4 wave point, the receiver came alive. Not great, but at this stage, I've essentially got a 1/4 wave attached to the shield due to skin-effect. Not recommended for permanent install, but maybe something for out in the field in a total emergency where no wire is around and all you can do is try and choke it.

I'd really love to model this in EZnec, but I haven't mastered transmission lines, or the choke as loads. So for now, I'm going by ear and what the MFJ tells me.