1661
« on: October 19, 2014, 0417 UTC »
If you want to skip a transformer, try an unterminated BOG, which is actually little more than a longwire on the ground. The tradeoff without termination is it will actually be somewhat directional off both ends. Use a ground rod and/or a small radial field for the RF ground. Wind a 1:1 feedline isolator.
My previous HF antenna of choice was a slight variation of the above. I used 148' of RG-6 coax for the antenna element. The feed point went to center, with the antenna coax shield floating. At the far end, the center was terminated to the shield. RF ground was just a ground rod. It was not very directional, but it was rather quiet for noise. Naturally, a decent preamp is recommended, too.
Moving onto my current antenna-on-ground setup, I have an 148' "shielded" square loop placed right on the ground. I went for capture area due to the ridiculously high ground losses incurred. The loop is built with RG-6 coax. The center conductor forms the loop, with each center feed feeding a 1:1 current bulun. The shields are bonded together at the feedpoint side and tied to a ground rod, then broken at the symmetrical far side from the feedpoint. RG-6 for feed line, with multiple ferrites installed at random intervals.
The loop-on-ground is routinely used for longwave to mid-HF, usually without a preamp. There is a distinct falloff above ~10MHz, even with a preamp. I often use the loop even for listening to longwave broadcasters across the Atlantic, again without a preamp, which I think is decent considering my suburban location.
Show Posts
