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The Needle, narrow vertical loop antenna plan

xm49north7

xm49north7

Well-Known Member
Mar 21, 2019
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Here is a drawing of my current antenna. It is a full wave loop, side fed , vertically polarized. I replaced my quad loop with this, as it has better takeoff angles for dx, and is omni directional. It is up at 36 feet to the feed and is working well. Have not had it on the dx yet, but getting out as good as the quad did locally.mg nedle antenna complete.jpg
 
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I hope to get it up higher over the next few days here it is modeled a little higher and over my tin roof, second story on a metal lower section mast and fiber glass upper pole within the loop area, I can verify this is much more omni than the quad loop this replaced, got some great reports off the side today, equal to off the front.Needle tin roof.jpg
 
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So have this up now at 50 feet to the top, getting out very well, I have moved the coax out of the loop, so it comes off the side feed,and away. The high voltage points at the bottom of the v, are no place for the coax to pass. Getting great swr, below 1.5 across the board.with coax out the side. I used a spreader wider than the loop, close to 2 meters, to attach the coax too.
 
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Running this with a 4:1 balun and a choke coil, at the feed of antenna, both wound on a scrap of white septic pipe, slides over the end of the centre support. Balun is 1/4 wave coax 75 ohm velocity factor of 6, the length is 143 inches, and the choke is a full 1/4 wave, with no velocity factor, so approx, 108 inches, balun diagram below. Ignore the dipole in the diagram. Getting amazing results with this antenna. Works better than the many , many quad loops I have had up. Let me know if you need any more info, Will be happy to do what I can, will try and get actual shot of her in the air today.
folded-dipole-homemade-ham-radio-antenna-21650442.jpg
 
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Nice!im interested in trying one of these.Seems like a pretty good all around performer for what I’m doing.How high to feed point?
 
I have had it at 36 to the feed and 46 feet. I like to see an antenna at min 36 to the feed if possible. This thing just works, quite amazing, I have a shop full of antennas I have built; this is the first one the locals went wow, what are you talking on, Nearly doubled my send/receive over my quads, I have had many, many quads, this is a real step up. I presume it is that all wires are vertical and long, Do let me know if you give this a shot, feel free to hit me up if you need any info or help. I have had nearly every antenna there is, for some reason this thing just works better. I have searched the web for information I cannot find any. I developed this antenna just by playing in software over a week or so. It seems to work better than the numbers would lead me to believe. Quite stoked with this, but wish I could find some equations to explain it better.
 
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I highly recommend side mounting on a tower, I am getting 7 dbi off the front, and 4 off the back, and perfectly omni still. I have it about 63 inches off the tower. My loops used to suffer on the tower or were no better than in free space, but this one likes the tower and gets out better for sure.
 
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Just a note on the other side of the beam, people have asked. It is a piece of the same pipe with a bit of brick tywrapped inside; I weighed the balun and made a counter balance for the other side , just to make it hang nice, and the weight helps keep it tight. I also run masons line off each end of the spreader to ground mounted bungee cords, and one off the bottom of the v,,to keep it in place , it is rock steady even in a good wind.
 
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What’s your thoughts on mounting in a tree?i know it’s not ideal but I’d like to use it for kinda mobile POTA type situation for 11 meters as I don’t a tower for it at the moment
 
tree would be fine, much better a tree than putting any metal inside the loop, go for it, I hope you build this. I would be very interested in other peoples results, this one has really surprised me. I have had this up in 2 places, one with balun at the radio, one with balun at the antenna, both places I got most excellent results. I am in the process of putting one up for horizontal. I am bust taking apart my old quads, I will not need the quads, this diamond works so well. I will be just running diamonds from now on. I look forward to hearing theories why this antenna works so well.
 
Ok.Ill post results if I get around to building this.it might be awhile since spring is a busy time at work.75 ohm for the balun?
 

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