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## Re: [TowerTalk] 160m inverted l

 To: Re: [TowerTalk] 160m inverted l Sat, 9 Dec 2006 22:03:33 -0500
 ```Or you can calculate it and only trim your wire only once 234 / resonate frequency - 234 / desired frequency = amount to trim (or add if negative) This will also work with a dipole if you trim off this amount from each side. John KK9A / P40A To: Subject: Re: [TowerTalk] 160m inverted l From: "Dale Martin" Date: Sat, 9 Dec 2006 14:05:08 -0600 If you've got an antenna analyzer like the MFJ-359, you can see where the SWR is minimum. Cut off a few inches of antenna. See where the new minimum SWR point is. Then you can figure how many kHz per inch the minimum SWR point will move with each subsequent cut. For instance, cut off 6 inches of antenna and find the minimum SWR moves from 1818 to 1824. So, the kHz per inch is 1 kHz per inch. If you take off six more inches, the minimum SWR moves to 1830, or 10 inches to move to 1834, etc. Of course, it pays to be conservative when your are cutting wires, so always cut for a lower frequency than the actual target until you get with a couple of inches. For my 1/4-wave half-sloper on 80, instead of cutting the wire to move it into the phone band, I simply bring the antenna end back on itself to shorten the overall antenna. I use the same method of calculating how much will move how far, but without cutting the wire. :-) 73, Dale, kg5u _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists.contesting.com/mailman/listinfo/towertalk ```
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