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Tnx to both Richard and Cecil et al, I think I am good to go. I will most
likely use the uninsulated wire for the diy ladder line. Although I do not quite understand the thing about stubs and am not sure how I would be able to measure anything along the ladder line since it is actually high up in the air for the most part (I might be able to measure something at its ends tho....what exactly does one need to be measuring up there?). Sorry to be so Elmer-needy.... I just happen to have a bunch of that black poly 1/2" irrigation tubing, which cuts up easily, and is apparently a good choice for diy ladder line because of its UV tolerance. There is no foil-backed insulation to worry about coming into the house peak or ceiling. I have a bucket of those old porcelin knob&tube feed thru dealies out in the barn. I am making some masts out of whatever I can recycle, mostly old metal tv telescoping masts. I will have to guy them if I get them up as high as I possibly can for the four corners of the loop. I was thinking of using pulleys and dacron for the guys, pulleys so I can redo the guys after years...and they look like they are about to fall apart etc. without having to take down the poles.....or should I use wire for guys? The masts are metal anyway, maybe wire guys are ok, what do you think? -Zeno (although I probably will be "Bill" when I finally get on the air again) They just gave me KG6UHM, but I think I either want my old expired call back or concoct something new....with good cw rhythm....and "phonetics" which reads like a novel...... Richard Clark wrote: On Wed, 14 Apr 2004 06:43:35 GMT, zeno wrote: Should I just go with the 4" spacing because it looks cool? Fer Sure, Dude! The choice is simply one of maximizing copper to minimize loss. If you expect a wide variation of Z through using the radiator across a larger variation of frequency, it is hard to choose one single determiner of line Z outside of this consideration. You could use the same logic to select 50 Ohm line (there is absolutely nothing magical about the value); however, cost becomes prohibitive due to a larger conductor for the inside lead driving the size of everything else to obtain the same loss figure as the cheaper, simple twin lead construction. So, there you have it, cool and cheap (true to only the frugal Amateurs's perception of reality). As for another question about coming in through the wall. You idea would work suitably. The only problem is in having it penetrate house insulation that is foil-backed (without you being aware of that being so). Some would offer the penetration presents no problem as it is for a very small interval. In the large scheme of things, quite true; and yet as a site dislocality (humorously called a bump in Z) this is where additional SWR will be present with a corresponding magnification of V and the possibility of breakdown. This is unlikely, but this would be where it happens if "likely" occurs. As things go, it is all a probabilistic issue - the insurers have tables for this. 73's Richard Clark, KB7QHC |
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