HFU HF Underground
Technical Topics => Equipment => Topic started by: NJQA on May 23, 2021, 1255 UTC
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Detailed analysis and report on a 630M Loop on the Ground Antenna.
https://rudys.typepad.com/files/630m-log-notes.pdf
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Very interesting! Thanks for sharing this.
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Dropping a little further down in frequency, I use my 148' coaxial "shielded" LoG for listening to longwave broadcasters when conditions permit.
No matching. No preamp needed for longwave, either. Just straight to the coax. I do have a few snap-on ferrites on the feedline, plus a decent RF choke near the receiver end.
I should get around to parking a SDR on the 630m and recoding a day or two to check reception.
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How is it on HF?
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It is often my primary HF antenna under 15MHz for regional reception out to like 1000-1500 miles. It works quite nicely for stateside 80m-40m monitoring.
The primary lobe of reception is upwards. Think more or less NVIS for 160m-40m. It can receive DX, but a low-hanging NVIS dipole can as well depending upon propagation.
Performance rolls off pretty fast above 15MHz. A preamp can extend it further upwards if desired, though it probably breaks into numerous lobes at upper HF among other considerations, so it can become a huge YMMV compared to even something as simple as a 9' vertical.