HFU HF Underground
Technical Topics => Equipment => Topic started by: ChrisSmolinski on June 14, 2019, 1937 UTC
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I was wandering around in the yard and noticed the sky loop wire was broken at one location. This is a horizontal loop antenna, about 670 ft long, fed with a 4:1 balun and coax. Of course the break occurred in such a way that while one end was laying on the ground, the other was about 15 feet in the air. The sky loop has been up for ten or so years, so many of the support ropes are a permanent part of the tree they are in, and cannot be lowered any more. I managed to use an extension pole and wrapped the antenna around it to pull it down. It slipped off, so I had to repeat it about a dozen times until I could finally get it to where I could reach it. I spliced in a short section of new wire along with an antenna insulator and pulled that up another tree to elevate that section of the wire.
For fun I ran SDR recordings on the upper end of the MW band as well as the 49 meter band on two SDRs on the sky loop while I did the repair work.
The only signal on 49m was CFRX 6070, which gained about 10 dB when i repaired the antenna and hoisted it back up
On the MW recording, some stations got stronger by up to 10 dB or so, while others got weaker, I assume the directional pattern of the antenna changed. My semi-local pirate on 1620 got much weaker. I can get a pretty decent signal from it on my crossed parallel loop antenna however, which is directional on MW. Still interesting to see the effects.
Although now I guess I have a 675 ft sky loop antenna ;D
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Well done! A friend had a 500ft loop atop phone poles and it beat all his other antennas for hf and ambc rx, some of wich antennae were at similar or even greater heights. Before the loop his RF Systems crossed loop actives were superior. I had a loop tacked under the eaves of the house and fed by tv coax, worked great! The TS850 would tune it to 80m and most other bands with no probs.
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I can tune the loop on 160, 80, and 40. Above that things get cranky, no doubt because it is multiple wavelengths long. But yes, for reception it is great all over MW and HF. It's my pirate magnet ;D
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Loops are a signal snare, or a signal lasso.