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Amateur Radio

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    $\begingroup$ re your grounding question, check out this answer that separates the grounding of a mast, equipment grounding, and an RF ground plane. Also, check out other various and sundry ground related Q&A here! $\endgroup$ Commented Feb 13 at 19:51
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    $\begingroup$ Also, you should note that moving the feed point of your antenna will change its tuning characteristics! Put the antenna on the mast, and "trim" the ends by simply folding the ends back. That way you can non-destructively experiment. $\endgroup$ Commented Feb 13 at 19:55
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    $\begingroup$ Finally, start with the lowest band you'll be operating on. $\endgroup$ Commented Feb 13 at 19:57
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    $\begingroup$ When tuning a multi-band antenna, it's good to do an SWR "study", by recording your lowest SWR in each band you intend to use the antenna on, since shortening it to move the "best frequency" in one band, may cause your best SWR to be "too high" in another band. So you may have to compromise to get a decent, but not "perfect" SWR across all of your bands. As far as how long your counterpoise should be, that antenna looks to be a center-fed sloper, so each leg should be the same length & UnGROUNDED. You do NOT need any radial field with a dipole, you are just distorting your radiation pattern. $\endgroup$ Commented Feb 14 at 17:11
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    $\begingroup$ Yes, I use an MFJ-269 Antenna Analyzer and "map" the antenna by band and SWR low point on the band and SWR at the target frequency center for the band. Turning the antenna wire back on itself to test before trimming is a good point. Another part of this "project" is grounding and connecting the ground to the existing ground for the house to prevent ground loops. I get mixed reviews in the various antenna books on counterpoise and even some antenna manufacturers say that the counterpoise for their antenna should be grounded. I don't see that in the literature of books on antenna design. $\endgroup$ Commented Feb 15 at 16:15