Roger Parsons wrote:
I have separate 7MHz and 10.1MHz quarter wave vertical
antennas which are spaced about 60' Both have about 60
radials and the radial fields do therefore cross each
other to some extent. There is a very small amount of
interaction between them, as one would expect, but not
enough to significantly affect the matching. The feed
impedances are much as expected, so they both seem to
be working as they should be. They are both fed over
the same hardline feeder with a switch box near the
antennas. I am sure there are no feedline, switchbox
or matching faults - I have physically exchanged the
feedlines.
The 10.1MHz antenna works beautifully - I snagged YV0D
the first call after I found his listening frequency
last night in a major pileup. The 7MHz antenna is a
dog, which is very easily beaten in all directions and
distances by a dipole at 40'. (The dipole is about
300' from the verticals and has a higher loss
feedline.)
Now why should that be?
73 Roger
VE3ZI
Hi Fellow Roger....
If I were to venture a guess I would say that was propagation.
Sometimes the low angles are favored (vertical) and sometimes
the high angles (dipole). I would try more comparisons over
longer paths through the Winter months. I suspect that you will
find some long path signals where the vertical handily beats
the dipole. Most DXers have both a high angle and a low angle
antenna for just these situations.
Good luck and DX, Roger
--
Remember the USS Liberty (AGTR-5)
http://ussliberty.org/
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