Hi Kirk
To get the feel of a vertical, could you try shorting the feedline of the
dipole together at the shack end and load it up as a top loaded vertical
(with some radials of course)?
Might be better than a really short vertical. 73
Tom W7WHY
On Thu, Nov 3, 2016 at 10:41 PM, Kirk Kleinschmidt via TowerTalk <
towertalk@contesting.com> wrote:
> Hi, gang,
> I'm in a bit of a race against the clock (the winter clock), and I'm
> trying to get a vertical up in the back yard that might be useful on
> 160-40. (Never used a vertical before, but I wanna.)
>
> Assume that I have plenty of 50-foot radials or a 500-square-foot
> galvanized ground screen (Rochester reportedly has excellent ground
> conductivity).
>
> My other antenna (until Spring, when towers can go up) is a 102-foot
> doublet fed with open-wire line, up about 40 feet (not exactly killer on
> the low bands for DXing). The vertical doesn't have to be "the final
> design," as it can be changed in the Spring, but it does have to be quick,
> as my pre-winter window is closing soon.
>
> I am thinking about feeding it with an SGC or Icom autocoupler for ease of
> multibanding, but I would consider making dedicated feeds for various bands
> (100 W max for this first winter season).
>
> The main vertical element will be a 30-foot length of aluminum irrigation
> pipe, either 3 inches or 6 inches in diameter. I'm not sure yet, as I don't
> know which will be available to me. The 6-incher is 70 miles away, the
> 3-incher is 120 miles, and I have to transport these pipes with a Ford
> Focus and an 8-foot utility trailer (and lots of back roads).
>
> 30 feet is close to a quarter-wave on 40, of course, and I can add a
> top-mounted loading coil. a top-mounted trap, a capacitance hat near 30
> feet (like a 20 meter quad loop mounted parallel to the ground), or a
> 22-foot fiberglass "whip" with heavy-gauge aluminum wire inside (or a
> combination).
> Without presenting "too-crazy" impedances on one band or another, is there
> a "magic formula" for something like this, or is the frequency span just
> too great?
> As always, thanks,
> --Kirk, NT0Z Rochester, MN
>
> My book, "Stealth Amateur Radio," is now available from
> www.stealthamateur.com and on the Amazon Kindle (soon)
> _______________________________________________
>
>
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