The interaction between various wire antennas may be more than "minor".
I have a half-sloper on a tower (a two-wire version, for 160, 80, 40). The
tower becomes the primary half of the antenna and should have a good RF
ground (that is, radials). I doubt that you could both shunt-feed the tower
and use it for a half-sloper antenna --- that would make some really odd
interaction.
As many people have found, half-sloper antennas are unpredictable.
Sometimes they work very well and sometimes they are terrible. Mine is
middling. I get out on 160 and 80, but it is quite noisy. (The match on 40
is very bad, but I have another antenna for 40). I was concerned about
interaction between the half-sloper wires and my beam, so I moved the
half-sloper connections to a point 1/3 down the tower; it did not seem to
make much difference. I have 30 radials (30-60 feet long) on it.
A suggestion: If you are just getting started with ham radio, do not worry
about trying to cover all the 160-10 meter bands with good antennas. This
would be quite unusual for a startup installation. Define your interests.
If you intend to chase DX, then forget about 160 on a small lot. Also, do
not overly worry about small SWR mismatches. With short coax runs (on your
small lot) a 2:1 or 3:1 SWR on 160/80/40/30 meters is not significant,
providing your rig does not begin to "fold back" at these levels.
Bill
W2WO
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