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Hello I want to explain a bit about Half Square antennas. I do have the 100 foot tower and tried it on 160, it works ok for transmit but not for receive as the noise is extremely high. In my previous QTH I had a 140 foot vertical made from irrigation pipe with 40 feet of top hat. It worked absolutely like a dream for transmit but as with my tower was a disaster on receive, however there I was surrounded by wheat fields and had 8, 1 wavelength beverages on the eight compass points. I could hear very well and transmit same. I actually had that vertical in this new QTH, but I have no room for the beverages. As a result of having so bad receive I got lazy and did not keep my guy's (Poly Rope) tight as I should have and around 1995 we had a bad storm hit and had wind gusts of 100 MPH for a week. I was stuck in the house with pneumonia and I knew the vertical would probably come down, but had no options, it took three days to bring it down, but at last it did. After that I was just not interested in putting up another pipe vertical. I was blessed however to run into another ham here in the valley that had this 100 foot tower and his XYL wanted it gone "NOW", so I was able to get it as it was not beyond my budget. Having tried the tower for an antenna on 160 and seeing it would not work I did some investigating and found this website Half Squares and was able to put one up temporary using one of my own trees and one on the vacant lot next door, with the owners permission of course. It was constructed the same as the one shown in figure 3 of that website, except that one is for 80 meters, so all dimensions are close to double and a tad more, 273 feet long, 136 foot verticals at each end, bent back under the top horizontal wire at half way down approx 68 feet leaving the bottom folded wire about 10 feet above ground level to allow clearance. I do feed one end as this gives you high impedance feed and is not so ground dependant, I use a circuit shown in that website article in figure 10 sketch A. I wanted the ability to run my amplifier so constructed that tank circuit in a different way, I do think out-of-the-box. I went to Lowe's and got one of their 5 gallon plastic buckets, not expensive. As I was an electrician I had a roll of number 6 bare copper wire, I wrapped it around the outside of that bucket leaving about 3/8 inch spacing between turns. I was also blessed to have a 350 pf vacuum variable in my junk box that had a flange fitting on the front so I was able to take a hole saw and mount that vacuum in the bottom of the bucket with the knob on the outside and the rest of the capacitor inside the bucket as it was going to have to set outside as there was no way to get the end of the antenna in any structure but being inside the bucket I only had to set it upside down and it was nice and dry in there. I did drive a ground rod at the feed point site and connected the bottom of the coil/and capacitor to it as they are in parallel, and coax shield. Then connected the end of the antenna to the top of the coil/capacitor. I put as large a knob as I could find as this end of the capacitor would be hot. I was able to get some power out there at the feed point site and hooked up my TS-830 to a short piece of coax with alligator clips on the ends. Set the cap about mid turns and started moving the coax center alligator clip up and down the turns on the bucket, finding the lowest SWR I then turned the Vacuum Variable and adjusted the alligator clip until I found a very low SWR 1-1. I then hooked up the coax from the house and went in to make final adjustments as the long coax was sure to add additional capacitance, and it did but only took about three trips in and out to adjust the capacitor so the antenna was 1-1 on 1.825 and could go to the bottom of the band with only a 1.5-1. Now that the antenna was ready I waited until dark and started listening and tuning, but of course the band had taken a dump as we were having a lot of northern light activity here. So every night I would sit in the ham room and leave the receiver setting around 1.825 and do work. I was a bit skeptical as there was so low noise, but a good friend Bob WA7OFH and I talked about it, and he had built a bobtail curtain back in the 60's and he thought the same as it was so quiet but then one night he started hearing Europeans, and worked quite a few, that was when we only could run low power and the fellow that designed the bobtail curtain also designed the half square first, but no one figured such a simple antenna was any good, so he added another section and called it a bobtail curtain. So I sat and listened and did work in the ham room every night. About a week after putting it up I was sitting working and started hearing a station calling CQ but having been off the radio almost entirely for about 5 years I was taken back by the call it was J5C I thought it was a pirate, but a lot of people started calling him, so after he called about three times and answering no one I put my call in and he came right back and gave me a 599, that was on January 22, 2008. I then knew I had a winner, but the next summer my neighbor announced he was going to build a house next door and I couldn't use his tree any more, was a sad day HIHI. I had a pile of used irrigation pipe I had gotten from a local farmer, it was used and most had a bit of a warp in them, but I figured I could get at least and 80 foot piece up without too much of a problem and two sets of metal guy should hold it ok. So I put one as close to the NW corner of my place as I could and then measured out where to put the other one to give me a right angle to Europe as these are a bi-directional broadside antenna. Actually that is not a bad deal, you can work short or long path on one antenna. The radiation angle with a half square/bobtail is less then 10 degrees, man made noise is much much higher than 10 degrees so the antenna is not very receptive to high angle signals which is why it is so quiet, it does not hear those high angle man made noises, it is not uncommen for me to have a s0-1 noise level in winter low solar flux times. This antenna would not be one for close in rag chew type operation, in that article he advises that this antenna starts to work best at a distance of 1500 miles or more. As he says if you have room for a full size half wave dipole you have room for a half square. After using this antenna on 160 for one season and not being able to work into Asia I put up that other tower and now have 4 directions I can work and they for some reason do not interact, I can hear a station very loud in EU and turn on the Asia antenna and cannot even hear the station in EU visa versa is same. I have since built a 40 Meter Half Square supported between two of my guy lines from the 100 foot tower. I feed it differently, but still shown in that article figure 10 sketch C, you make a piece of open wire velocity cut for a quarter wave long, this means one end is very low impedance the other is very high, I connected one end to my Johnson Kilowatt Match box, the balanced wire connection, both wires, the other end only one side of the open wire connects to the antenna the other side of the open wire is free, connects to nothing, now how do we do that, its because of the physics of the quarter wave length of open wire, it thinks its connected on both sides as its looking for a very high impedance so it matters not that its only connected on one side, that is exactly how we used to end feed a hertz antenna, look it up. This antenna is broadside to EU/VK and does it work on 40, is also a dream there. I really enjoy my half squares and they do transmit better then my 100 foot tower did also. Thats because the current point of that tower is on the ground, with the half squares the current point is 80 feet up in the air, Hope you enjoyed the story ,73 gl gb
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