What - why rx-only?
Testing my "loop on ground" inspired by Matt, KK5JY reveals that the directional pattern is somewhat similar to a typical low inverted-vee. But there's a twist.
We all know that bringing a dipole or inverted vee low to the ground makes it more or less omnidirectional and kind of "cloud burny" with no low angles.
One way to get those low angles is to squash the pattern by going to the extreme, such as putting it right on the ground. That's the subject of the "log" or "dog" antennas seen here:
https://forums.radioreference.com/receive-antennas-below-30mhz/370110-160-20m-log-loop-ground-2.html
BUT, for those who don't want to believe, and need something "in the air", we'll do just what you nornally don't want to do when your antenna is designed to transmit! Get it *really* LOW.
1) Build your inverted vee, but since this is designed for rx-only, bring the ends as close to the earth as possible! We're talking no more than an inch off ground! Bad for tx of course, but good for squashing the pattern for low(ish) rx angles. Your typical 20 meter inverted vee lengths will do.
2) CHOKE AND ISOLATE the feedline at the feedpoint. Otherwise, don't waste your time. Slapping an ineffective "ugly balun" doesn't cut it! We're talking about using a galvanically isolated (physical separation) transformer. And now your sleeve ferrite chokes. Do what you have to to truly isolate the feedline.
3) Don't get hung up over resonance. This is a non-resonant broadband antenna. I haven't yet determined the best impedance ratio transformer, it 4:1, 9:1 etc etc, BALun. Preferably not an autotransformer, but if that's all you got, immediately follow up with a 1:1 galvanically isolated transformer. You get the idea - don't make the feedline part of the antenna! Don't go half-way with a few random ugly loops of coax.
You can see the results in EZnec - even the demo version. Bring those ends down to 0.5 (zero point five) inches away from ground.
Right - I haven't built this yet. My "invisible" rx-only squashed inverted vee is in the shape of a loop on the ground. But for those who want something in the air, purposely built for rx-only, this might be a great project.
Testing my "loop on ground" inspired by Matt, KK5JY reveals that the directional pattern is somewhat similar to a typical low inverted-vee. But there's a twist.
We all know that bringing a dipole or inverted vee low to the ground makes it more or less omnidirectional and kind of "cloud burny" with no low angles.
One way to get those low angles is to squash the pattern by going to the extreme, such as putting it right on the ground. That's the subject of the "log" or "dog" antennas seen here:
https://forums.radioreference.com/receive-antennas-below-30mhz/370110-160-20m-log-loop-ground-2.html
BUT, for those who don't want to believe, and need something "in the air", we'll do just what you nornally don't want to do when your antenna is designed to transmit! Get it *really* LOW.
1) Build your inverted vee, but since this is designed for rx-only, bring the ends as close to the earth as possible! We're talking no more than an inch off ground! Bad for tx of course, but good for squashing the pattern for low(ish) rx angles. Your typical 20 meter inverted vee lengths will do.
2) CHOKE AND ISOLATE the feedline at the feedpoint. Otherwise, don't waste your time. Slapping an ineffective "ugly balun" doesn't cut it! We're talking about using a galvanically isolated (physical separation) transformer. And now your sleeve ferrite chokes. Do what you have to to truly isolate the feedline.
3) Don't get hung up over resonance. This is a non-resonant broadband antenna. I haven't yet determined the best impedance ratio transformer, it 4:1, 9:1 etc etc, BALun. Preferably not an autotransformer, but if that's all you got, immediately follow up with a 1:1 galvanically isolated transformer. You get the idea - don't make the feedline part of the antenna! Don't go half-way with a few random ugly loops of coax.
You can see the results in EZnec - even the demo version. Bring those ends down to 0.5 (zero point five) inches away from ground.
Right - I haven't built this yet. My "invisible" rx-only squashed inverted vee is in the shape of a loop on the ground. But for those who want something in the air, purposely built for rx-only, this might be a great project.