[TowerTalk] Quarter Wave Sloper (half sloper)

[Bill Ogden]

I have a similar halfsloper (40/80/160) attached to a 55-foot crankup tower
with a SteppIR on top,  I initially attached the sloper to the top of the
tower, but later moved it to the top of the middle section of the crankup
tower.  There is also a terminated dipole hung from the top of the tower
(with a rope allowing it to hang down a few feet; the dipole is at right
angles to the half-sloper wires.  I could not tell much difference whether
the jalf-sloper was attached to the top of the tower or to the middle.

The tower has about 30 radials of various length (each an inch or so in the
ground).  I needed to move the half-sloper wires around a bit to make
things work.  I get about a 2:1 match over 1800-1860, about a 3.2:1 match
over almost all of 80/75 meters, and a 2:1 match over most of 40 meters.

I am not worried about the SWR per-se  (the coax is less than 100' long),
but the wide bandwidth on 80/75 meters should indicate high ground losses.
I seldom work 80 meters (and never work 75).  When I do call a "new one" on
80 meters I usually get through, so it is not too bad.  Again, I seldom
work 160 (CW only) but I can usually work most of the U.S., so the antenna
is "working" (however you want to interpret that).  I have the SteppIR
30/40 meter add-on option and normally use that on 40 meters.  When I
switch between the half-sloper and the SteppIR (on 40 meters) the sloper
almost always has higher received noise, but sometimes gets through better
than the horizontal SteppIR.  (The terminated dipole is a loser, at least
in my case.  It is almost never equal to (or better than) the sloper.)

>From what I have read, half-slopers are odd ducks and each user has a
different experience.  Your results might be completely different than
mine.

Several coaxes and control cables  (and a separate #12 wire) drop from the
top of the tower to the base, hanging outside the tower itself.  They are
not grounded or bypassed at the base (although I know I should do this)
except for the #12 wire, which is attached to the tower base.  Many of us
wonder about the connectivity quality of the crankup tower sections.  The
coaxes, control cables, and #12 wire, hanging along side the tower, must
couple to it and probably affect the operation of the half-sloper.

Good luck,

Bill - W2WO