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Old 02-20-2014, 08:16 PM
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DaveInDenver DaveInDenver is offline
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Join Date: Jun 2006
Location: Larimer County
Posts: 7,093

Model started, so far using the longer of the two (19" = 482.6mm) over an ideal ground is giving a fairly reasonable (as in not completely unbelievable) result. It looks like the feed line, NMO and maybe the SO239 are impacting the real installation, particularly on 70cm but even my 2m measurements vary a bit. I'm just modeling this as a single element with 124 segments, so it's pretty basic.

In any case, the elevation plot is interesting for the 3/4 wavelength case. My experience driving around today using this antenna on 70cm matches the pattern, it tends to fade a lot more than the 1/4 did. This is probably the biggest hurdle to doing this, that huge null at 22 degrees. Being down -20dB there is going to be a problem since that is where the majority of your repeater aspects are going to sit. OTOH it probably won't be the least bit deaf up against the hogbacks along C470. ;-)

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