I have a c4xl at 75' and a c3 at 45'. I like the combination.
Pete Smith wrote:
> At 06:32 AM 9/28/98 -0600, T A RUSSELL wrote:
> ...
>
> >>3) If stacking tri-banders, I will have to live with a height
> >>separation
> >>that is not optimal for all three bands. Does anyone believe that
> >>this is a
> >>major problem? Has anyone modeled a two stack of small tri-banders,
> >>and
> >>convinced themselves that the separation issue has a major or minor
> >>effect.
> >>Remember, I am selecting the stack in part because of the extra db of
> >>gain -
> >>if I am going to burn that db because of non-optimal separation, it
> >>would
> >>matter. Has anyone stacking tri-banders on a crank-up played games
> >>with
> >>lowering the tower to get better separation on 10 or 15 meters -
> >>modeling
> >>the net effect of the lower height vs better separation?
> >>
> > Your best solution here is to model it, or find someone
> > who already has done so. (Ask N6BT)
>
> See my article in July-August 96 NCJ for a first attempt at modeling a C-3
> stack. My results tended to indicate that a spacing of about 28 feet gave
> a decent compromise between gain on 20 and degradation of F/B ratio on 15.
> The 10-meter case is pretty far outside the normal stacking range anyway
> (almost a full wave).
>
> I also recently looked at a 3-high stack of C-3s with the antennas only
> about 20 feet apart, thinking that I might get better performance on 15 and
> 10, then "cut out" the middle one on 20. Trouble is that you can
> disconnect the feedline but all those resonant or near-resonant elements
> are still there, so the 20-meter performance looks terrible.
>
> My current plan, for whatever it's worth, is to install a C-4XL at 97 feet
> -- building it now -- and stack a C-3 at 69. Since the 10-20 meter
> sections are identical, that should give me good 10-40 meter performance.
> I know Tom'll say I need a third C-3 down at 35 feet or so, but one thing
> at a time!
>
> 73, Pete Smith N4ZR
> In wild, wonderful, only middlin' rare WEST Virginia
>
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--
73,
Richard Thorne
Amarillo, TX
Amateur Radio Station: N5ZC (previous calls, KA2DSY, N2BHP, WB5M)
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