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Re: # 14 stranded copper wire

Discussion in 'General Technical Questions and Answers' started by K9STH, Dec 9, 2001.

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  1. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    I would like to see the original Bill Orr (W6SAI) reference and not just someone's comment that Bill Orr had made this reference. Also, in a number of the old ARRL "Hints & Kinks" book, there is a parallel dipole made from 4 or 5 conductor flat rotor cable. This is definitely insulated! The dimensions are the same as with bare wire. This antenna performs as designed.

    Also, for a number of years (back in the early 1970s) I was one of the contributing editors of CQ Magazine. Frankly, quite a number of the things that were published by CQ in the form of books were not examined for technical quality, only for how well they "read". I have found quite a number of errors in the books published by CQ. The ARRL is not immune from this as well. There are numerous problems with schematics, formulas, etc., in various editions of even the ARRL Radio Amateur's Handbook. Some of these were published for decades!

    I was not responsible for any of the "editing" that took place on the CQ books.

    Frankly, I stand on my experience with wire antennas: For all practical purposes, insulation does not affect the wire length. It will take an opinion of a recognized antenna expert (I'm talking about someone who does antenna design day in and day out for a living - Dick Fenwick where are you!) to make me even think about whether or not insulation affects the length.

    I have never seen in print (that I can remember) any comment about insulation affecting either the performance of a wire antenna or its physical dimensions. I have seen numerous "arguments" as to whether or not to leave the insulation on because of the added weight.

    If the addition of insulating material affected the performance of an antenna it would most definitely affect microwave antennas. However, manufacturers of "dish" microwave antennas provide optional "radome" type covers made of insulating material that are installed with NO adjustments to the dish and that have NO affect on the performance. I think those manufacturers know a little about the effects of insulation!

    I would like to see the theory behind the statement that insulation affects the length of the wire and not just one person's "opinion". Frankly, I don't think there is anything in physics that allows for this. However, I might be wrong. But, until someone comes forth with the "accepted" (i.e. published in one, or more, industry or scientific community "prestige" publications) references (and I don't think there are any) showing the proof that insulation has a marked effect on the length of a wire antenna, I will continue to use the formulas to cut my insulated antennas that just happen to come out with the correct lengths!

    Glen, K9STH




    Contact: gzook@attbi.com
     
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