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#1
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![]() Thank you to Cecil, Reg, Mark, Asimov and Richard. I have read what you said and done more reading about Cap Hats. The Cap Hat doesn't improve the inductor, it basically replaces it, at least in part, which removes the loss of the inductor. I misunderstood that somehow. What I will focus on, then, is to create some form of capacity hat for each appropriate band together with an adjustable vertical length for tuning to the appropriate frequency. Mark, You may have a point about the dipole being better, especially for portable operation. I just want to experiment with the aluminum poles I have. I may take your advice and use them to create a portable tower in the long-run. But first I think I will try out the vertical. Thanks to all, Buck N4PGW On Wed, 23 Mar 2005 12:56:34 -0500, Buck wrote: I have aluminum poles of three diameters, 1.5, 1, and .5 inches. I have enough of the first two to create a pole of about 15 feet each and about 8 to 9 feet with the 1/5 inch poles. The poles are no more than 4 feet long each, but they are able to tuck inside each other, at least for the same diameter. What I want to do is to make up a 'kit' with these that I can take to the field to setup whatever antenna I want to use at the time. For example, I might set it up as a 20 meter vertical in one configuration, but in the evening, I might reconfigure it to 75 meters or 15, or 30 or whatever I desire. One consideration is to create a high-q coil for it. I am thinking of using 1/4 inch copper tubing to make a ten to twelve inch diameter coil so I can match it to the lower bands. I have been reading that base loaded coils have to be matched to the antenna, but center loaded verticals are more closely matched to 50 ohms. from what I have been reading, the center loaded coil requires more turns and a top loaded coil even more. A capacity hat is also a viable option. I am wondering how much I am helping or hurting myself with the larger coil or if I would be better off with a smaller coil. One thought is to connect x number of poles, then the coil, then another set of poles or a whip to make the final adjustment for the match or to match the antenna by tapping the coil. I am open to all suggestions, but I am interested in knowing the best location for the coil and the best size for it. Thank you -- 73 for now Buck N4PGW |
#2
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![]() Mark, You may have a point about the dipole being better, especially for portable operation. I just want to experiment with the aluminum poles I have. I may take your advice and use them to create a portable tower in the long-run. But first I think I will try out the vertical. You could probably rig it up to do either, if the vertical is stout enough to support a dipole/s. I have a couple of drive on masts that I use with the fence rail masting. Two of those makes 20 ft, and a good support for dipoles, or other antennas. For industrial use, I have a tower and beam I can drag around...I've drug it to the last four field days...Wonder if I'm gonna make it five..?? It's a lot of work for a two day deal....:/ I'm almost tempted to take a field day vacation for a year...Have to see...MK |
#4
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Dear "Asimov" w/o a call sign:
If you look closely, you will see that the "coiled up ribbon" is a transmission line or a pair of transmission lines. By elevating the antenna, which must be connected to the truck through at least one transmission line, much improved transmission range is effected. 73 Mac N8TT -- J. Mc Laughlin; Michigan U.S.A. Home: "Asimov" wrote in message ... " bravely wrote to "All" (24 Mar 05 09:41:39) --- on the heady topic of " Loading Coil Q" snip Lately I've seen TV media trucks with a type of rather wide pole of what seems to consist of a large coiled up ribbon. When they get to a location they unfurl the tube and it raises the microwave antenna. They seem to be made out of plastic or carbon, not sure. The one I saw went up about 30 feet. It seems very lightweight in any case. Anyone here know what it is? A*s*i*m*o*v |
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