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Lengthen or shorten?


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  • Ionosphere

I was building my new dipole for 40 meters and cut the "legs" to about 36 feet to allow room for tuning.  I was aiming for 7.185-ish.
The SWR was maxed all the way in the red at 7.185 and I couldn't remember if I was supposed to shorten it or lengthen it. 
Chopped off another 10" and this is what I got.
I was afraid I was going to accidentally cut it short and I don't like to splice dipole wire for the moisture to get into the strands.
Glad it worked out, 12 gauge copper is about as expensive as gold nowadays.

1.2 SWR.  I can live with that!

I guess Im going to have to write that on the back of my analyzer.  Old minds forget fast.   LOL

"Increase frequency, decrease wire."
Fixing to tape that to my analyzer.  Old minds forget.  Did I say that already?  I forgot.   🙂


Edited by KD3Y
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  • 2 weeks later...
  • Elmer

Has anyone responded to this post yet?  Here is what you are supposed to do. Find out what frequency the SWR is the lowest. At this point, it should be near 7.183 MHz.  If the lowest SWR is at a lower frequency, the antenna is too long. If the lowest SWR is at a higher frequency, the antenna is too short.  As you say, 1.2:1 is very good and not a concern. Also, the best measurement is when the antenna is at its final height. You might use the analyzer to see over what frequency range the SWR remains below 3:1. That is the range over which the antenna will perform well. Since it is a 40 m dipole, you should also check the 15 m band. Often an antenna tuned on 40 m is very useable on 15 m.



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