I have had excellent success with the clothesline pulleys. They are clearly not life-rated or mariner quality, but for ham antenna use I strongly recommend them. I have had several in trees/sky for 5+ years and have not observed any UV degradation.
Tim N3QE On Sat, Sep 20, 2014 at 10:06 AM, Jim Garland <[email protected]> wrote: > I want to replace the 450 ohm ladder line for my two DXE 720 ft long > bi-directional beverages with two lengths of WD-1/TT field telephone wire. > The wires will be secured only at the ends, but will be suported along > their > length by ceramic insulators mounted on 4x4 posts spaced every 60 ft. The > spacing between the parallel wires will be about six inches. Here are my > quesetions: First, does anybody know what the likely impedance is of this > configuration, or if not, how to measure it? Second, if I keep the DxE > matching trnsformers used with the 450 ohm ladder line, will beverage > performance be degraded noticeably with the new wures if, say, the > impedance > of the new line turns out to be 600 ohms or so? In other words, as a > practical matter how important to performance (e.g., F/B ratio and > low-noise) is it to make sure impedances are matched. > > > > Finally, a mechanical question. I want to have a pulley at one end of the > parallel wires to equalize the tension in the wires. I've not been able to > find a good pulley with a five or six inch diameter, except for nylon > pulleys used for clotheslines. Do you think one of these could be used. > There will be no motion of the pulley, since it is only used to equalize > tension. The field telephone wire is rated at 200 lbs maximum tension, and > I'm guessing the actual tension will be about half that. > > > > Thanks! > > Jim W8ZR > > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > _________________ Topband Reflector Archives - http://www.contesting.com/_topband
