Four and Five. The impedance may change by raising the ends, but your
problem on 15 makes me suspicious of lengths. Multiband antennas are
very touchy. Some recommend a second G5RV, scaled with 40 meters as
the bottom band. 73, Guy
On Fri, Feb 5, 2010 at 5:39 PM, Alain Michel <firstname.lastname@example.org> wrote:
> Hello All,
> New subscriber and relatively new to ham radio here! I am
> seeking your input on just how the lobes of the antenna are affected by
> the relative heights of the "arms" of the antenna.
> I am blessed
> with more than 4 acres of property. My antenna points to
> the NE and the SW. The feed point is up close to 40' or so on a fiberglass
> mast. However,
> given the height of the eucalyptus trees on the property, the relative angles
> of each half of the dipole are
> different. The property is on a slope and the highest spot on the
> property is the SW corner.
> The end in the SW corner is at about
> "10:00 o'clock" and 35 foot from the ground; the other end in the NE is
> about "3 o'clock" and about 40' from the ground. I cannot raise the NE
> corner [or the feed point] because I've run out of tree at 40'!
> However, the SW corner can go up another 8' or so [to 43'].
> The property itself resembles a very large soup bowl; high on the ends and
> low in the center. The antenna is hung from the lower left and upper
> right edges of the bowl [or in the 8 o'clock and 2 o'clock
> positions]. Nothing fancy here; just the G5RV and an IC 775DSP running
> barefoot. The antenna will work all bands from 160-10 meters accept 15...it
> don't like 21 MHz much at all!
> Which would be the best position for
> the antenna?
> 1) as parallel to the ground as possible
> 2) raise the SW corner 8' more and see what happens
> 3) lower the SW corner to simulate the NE corner
> 4) expect a negligible change regardless of
> what you do
> 5) leave well enough alone
> Many thanks for taking
> the time to respond!
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