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From online directions, I made a MURS antenna. The 1:1 SWR is at 142.000 and I want to tune it for 146.500 (therebouts). I know I need to shorten this antenna. I would like to confirm that I do NOT adjust the "4 radials" that project out horizontally, but only shorten each vertical. The online photo can be seen by searching for "High Gain Omni MURS jedsoft". My antenna looks identical and I need to know which part(s) to adjust to get a higher resonant frequency. Thanks!

Rick
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    Welcome to ham.stackexchange.com! Just for clarification for other readers, MURS is a radio service in the US that uses five frequencies between 151.82 – 154.6 MHz. The antenna you made can be sized for either the MURS band or the ham 2m band; yours is a 2m antenna, not a MURS antenna. – rclocher3 Feb 01 '19 at 03:13

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The antenna you reference is referred to as a Moxon antenna. All dimensions of the two elements are frequency dependent. I recommend that you use the AC6LA software to calculate the correct dimensions for your target frequency.

Glenn W9IQ
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  • Thank you so much for the education, that is what I feared but hey, I’ve been wanting software for designing anyway! – Rick Jan 31 '19 at 00:33
  • without having looked at this en detail: this is basically just a "slightly folded dipole" + reflector, right? don't think a 4% frequency offset is that... harsh. Does it really matter? – Marcus Müller Jan 31 '19 at 11:33
  • Correct, I was trying to make a 2 meter antenna with gain and it was based on a MURS antenna so it is not a MURS and the title I used is misleading. It is a Moxon antenna. It seems to have a very narrow bandwidth and I was trying to get a lower VSWR by tuning it closer to the frequency I wanted, a locally used simplex frequency. I believe my understanding is correct that I would need to adjust every aspect of this antenna for tuning and have been advised to use antenna software which would be a more efficient use of my time rather than adjusting by trial and error. Thank you all. – Rick Feb 04 '19 at 12:21