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#1
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![]() 2. There is about 100 ft between two unit chimneys. As no antennas are allowed, however there is a satellite dish at every turn, I would need to be super stealth and get permission from the neighbors that own the other chimney (good luck on that), but I could put a dipole between the two chimneys. I have looked into a vertical, but I have no room for radials. My patio is 6 ft deep and maybe 10 ft long. Any suggestions? 73 Greg ki4bbl Gregg, AL7KT, a friend of mine lives in an apartment that forbids antennas. He has a loop antenna for 80 meters on his roof that goes around four chimneys. The wire lays on the roof and 300 ohm TV twinlead (low-loss from rat-shack) comes down the corner and is painted the color of the apartments. His antenna accidentally fits on 80 meters and dips below 1.5:1 on all but two bands, one WARC. He uses the internal tuner on his Kenwood TS-440SAT and operates where ever his privileges allow. His concern is that the wire is literally ON the roof and that instead of being flat, it has the two inverted vee shapes on the two sides. The wire is number 14, but it is black and disappears against the dark gray shingles on the roof. Unless you are looking for it, the 300 ohm twin lead just disappears due to being painted like the building. The antenna mostly works well. In only three conversations, his loop outperformed my 80 and 40 meter sloping dipole hands down, but on 20 meters I was making contacts he couldn't even hear, but then my 20 meter dipole is about 75 feet or so high with one leg slanted upwards by about 60 degrees or so from there. We live about 10 miles or so in a crows flight and could barely hear each other on 20 meters. The little time we spent comparing signals could not be mistaken for being a valid comparison of antennas, but it did prove his antenna worked. If you can support and hide your coax from the feed point, you can consider using magnet wire for the dipole. The wire stretched between the two chimneys would otherwise go unnoticed. If you need more strength, you may be able to find some insulated small gauge wire, 18 or smaller, where the color blends into the background and yet the wire will withstand a little more abuse. If nothing else, I hope what I said help you get your wheels turning towards finding you a solution. Good luck -- 73 for now Buck N4PGW |
#2
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Very good idea. I am using a ts-520 with a pi-network so hopefully I
can tune it. I think I will give it a shot. I was worried about having it lay on the roof, but if experience states it works, I'm up for it. Ladder line will not work on the 520, but I do have a tuner that will match it, so I will give it a shot. 73 Greg ki4bbl |
#3
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On 25 May 2005 06:57:21 -0700, "Greg"
wrote: Very good idea. I am using a ts-520 with a pi-network so hopefully I can tune it. I think I will give it a shot. I was worried about having it lay on the roof, but if experience states it works, I'm up for it. Ladder line will not work on the 520, but I do have a tuner that will match it, so I will give it a shot. 73 Greg ki4bbl Al uses a 1:1 balun (w2au) blows my mind, but it works. I helped him raise the antenna and check for dips. -- 73 for now Buck N4PGW |
#4
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On Wed, 25 May 2005 14:34:02 -0400, Buck wrote:
On 25 May 2005 06:57:21 -0700, "Greg" wrote: Very good idea. I am using a ts-520 with a pi-network so hopefully I can tune it. I think I will give it a shot. I was worried about having it lay on the roof, but if experience states it works, I'm up for it. Ladder line will not work on the 520, but I do have a tuner that will match it, so I will give it a shot. 73 Greg ki4bbl Al uses a 1:1 balun (w2au) blows my mind, but it works. I helped him raise the antenna and check for dips. I just talked to Al, AL7KT on two meters. He says the 75 meter group which he meets every evening, tell him he sounds like he has an amplifier. He says that on 80 and 40 it is fantastic. He says that everyone keeps telling him he is doing it all wrong. The antenna is allegedly 100 ohms and he is feeding it with 300 ohm tv twin lead and then a 1:1 balun to a short piece of RG-8 (about 3 feet) to the rig. We don't know the true length of the loop as we didn't measure it, we just stretched it out and cut it where it came back together. We could estimate the length of the wire, I guess, or the twin-lead. Oh, also, the twin lead was laying on the ground. He took a staple gun and stapled it on the side of the building and trimmed off the excess so it no longer drags the ground. Before doing this, the antenna only matched two bands, now it matches all but two of the 80-10 meter bands including WARC, but I am not sure if he included 60 meters. -- 73 for now Buck N4PGW |
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