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Hi Cecil,
I've moved off the loop and noise suppression thread and over here because I'd like to consider an idea, and get yours and other opinions on the matter of adjusting the 300 ohm feeder length on the G5RV. On your G5RV page http://www.w5dxp.com/G5RV.HTM you state that if some method is devised to vary the length of the 300 ohm series matching section it could be made to work well on all bands. I was wondering about using a Lecher Wire Feeder in the shack. It would be fed from the rig by some 50 ohm coax, and then used as the beginning of the300 line feeder, the remainder would run out the window and up to the antenna. .. This would allow quick and easy of adjustment of optimum length for each band. For me, using 34 feet on 40M, and 23 feet on 10M, an 11 or 12 foot lecher setup would do the trick. I have seen your switched twin-lead arrangement and it is still under consideration. A couple of questions (which may give rise to more....) 1. How much radiation would I find in proximity to the lecher feeder and 300 ohm twin lead. Purely a health consideration It will not affect me as (1) I have worked around a lot of RF in my times -- as a tech at navy broadcast trasmitting sites, on Heavy Radars (Pinetree Line stuff), on shipboard trasmitting equipment, and 50 plus years of ham radio: and (2) I only run 5W maximum (if I'm lucky -- FT-817ND), and (3) I've already lost most of my hair, and (4) According to family opinion I lost it all (and I'm not talking hair) manyyears ago and am easily certifiable now! Is there a cure for Ham Radio RF overexposure? 2. How much variation in length could I get away with if I wanted to use a shorter lecher system, or would I get significant i.e. noticeable benefit by going to the optimum length for each band? I only operate non-WARC. I would happy restrict myself to the 80, 40 and 20M bands, and could drop 40 if the economics and physical reality make it worthwhile in terms of complexity and cost vs output. 3. How far from your operating position is your feedline/switching arrangement? Have you noticed any hair loss since implimenting the system? I am currently in a situation where an all-band dipole is out of the question physically, and I think that if it turns out worthwhile, I could set up a G5RV if I fudge a bit by bending the legs a bit here and there, I don't care about pattern, I just want to get a signal out where someone will hear it (hopefully). I would have looked up Smith Chart except that I didn't even know how to spell Smith! Thank you Cecil and any others who care to contribute toward this thread Irv VE6BP |
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