HFU HF Underground
Technical Topics => Equipment => Topic started by: bandarr3000 on June 10, 2018, 0002 UTC
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Has anyone ever used a single band dipole, or maybe even a G5RV (or it's Jr.) in a horizontally square configuration for transmitting? How about horizontally bent? I'm trying to get close to omnidirectionality while using an ideal space in my yard. An inverted V is an option, but I want to specifically find out if the "square dipole" will work. Thanks in advance.
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Well, not technically what you are looking for, as far as single band dipole goes, but I'm getting good results using an Inverted-L antenna from MW up to 17M. So far, I can tune up 160M, 80/75M, 60M, 40M, 30M, 17M, 15M, 12M, 11M, and 10M, with it with an antenna tuner. It seems pretty OMNI. I've QSO'ed in all directions and have not really noticed a hot spot direction, or a null. I am using a 4:1 W2DU current balun with it. When I think about it, my 6M Halo antenna is a dipole wrapped around as a loop, and that's OMNI. Don't know if that answers your question though.
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It is typically feed different than a dipole, but you are essentially describing a square halo. Take a look at a Cushcraft Squalo for example.
You might also be interested in looking at a 1/2-wave halo for ideas.
https://en.wikipedia.org/wiki/Halo_antenna
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Linearly loaded antennas usually work out just fine.
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What band, 43M? A Moxon Rectangle pointed up would probably work good for NVIS.
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I Have tried what you are talking about, I think. When I First got on HF ham radio, I was confined (or so I thought) to 40 meters and up, due to the size of my parents yard. I really wanted to get on 80 meters, and, not having any real experience, I tried almost everything. Bending the ends of the dipole in the same direction to make a 'C' shape, failed to tune, and I have no idea what the pattern was, as I was never able to transmit on it. After some reading, and help from a friend, I tried a 'Z'shape. The feed point was in the center of the 'Z', with each end bent in opposite directions. This was also somewhat of an inverted vee. I had the feedpoint about 40 feet up on some 1.5 inch steel EMT tubing which I had welded end to end, the bends in the 'Z' were about 20 feet up supported by trees, and the ends were about 10 feet up. The antenna was a little harder to tune than my 40 meter inverted vee, but would load up well, and seemed to work well in all directions. It was no larger than the "'C' shape, but significantly better. Something to keep in mind, the bending of the legs into a 'Z' shape will detune the antenna, so if you are operating on a single frequency, and wish to not use an antenna tuner, give yourself plenty of extra wire, and tune the antenna in its final position, also, the less bend you can get away with, the easier tuning will be.
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I only built one for TV channel 11 (201 Mhz). Being all or nothing digital TV you could still tell it had gain in the direction it was supposed to. The dimensions are pretty critical. Check here.
http://www.tippete.net/cgi-bin/moxgen.pl