7-band OCF dipole
80m 7-band off-center-fed dipole bought from gniklat1 on eBay.
Advertised to work on 80m, 40m, 20m, 17m, 12m, 10m, and 6m (tuner needed to cover all of 80m and 10m), with max power 300W PEP, 150W CW, 75W Digital. Advertised to work best in an inverted V configuration with the center at 25-30ft and ends at 8-10ft above ground.
Contents
Suspension
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Wiring
Measurements
Initial SWR measurements, 2020-09-21
Long end of antenna only ~6ft off the ground, support rope on long end only ~20ft off the ground.
From shack
Under antenna, with coax segment 1
After raising long end to ~8ft, 2020-09-23
Under antenna, with coax segment 1
- red = straight
- blue = with hand on coax ring
From shack
(Better on 2m than most of the bands it's supposed to work on...)
After raising rope on long end another ~5ft, 2020-10-06
The center is maybe a foot (or two??) higher than previously.
Under antenna, with coax segment 1
- red = straight
- blue = with hand on coax ring
From shack
After adding choke, 2020-10-25
I made a guanella-like choke, with 17 turns of RG-58/U coax around an FT240-43 ferrite. I found a perfect length of coax with just the right terminals, an old Radio Shack length.
In assembly and installation, I noted three things: 1. The coax segment I used for the choke is rather old, and is of unknown quality. 2. The PL-259 on the choke coax really didn't want to go onto the antenna, and I had to use a pair of pliers to tighten it, and ended up stripping most of the "grip" off the ring. I'm still not sure I got it on fully tightly—I think the teeth maybe mostly are locked in place but maybe not pushed up against the SO-239 so well? 3. The PL-259 on the coax that was attached to the bottom of the antenna (and which I then attached to the choke) had water inside it after I took off the "rescue tape" around it and unscrewed it. I wonder if there might be water inside the balun?
Under antenna, with coax segment 1
- red = straight
- blue = with hand on coax ring
From shack
