Hi Kirk: My understanding is that a sloper working against a tower is a sort
of dipole with the tower as one part and the wire as the other. I have found
that the sloper usually must be greatly different in length than 1/4
wavelength to achieve a low SWR. The tower is very much part of the
radiator. I think your tower is the main radiator and the sloper is a
matching system which does very little radiating. I think you have a good
system of loading your tower at present.
73, Dan, N5AR
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com]On Behalf Of Kirk Mohror
Sent: Monday, October 09, 2006 9:04 PM
To: towertalk@contesting.com
Subject: [TowerTalk] 40 meter sloper question
Explain this one.
Built a 40 meter ¼ wave sloper Sunday. Because of a 3 element quad, I could
only put it up at 33 feet. Grounded the shield to the tower and ran 35 feet
from the center conductor. Walked the wire out from the base to get an angle
of 45 degrees and stated to tune the antenna. Cut about 6 feet off the wire
and could not get the swr below 4:1. Moved the wire in closer to the tower
and retrimed the wire. Here is the strange part. I got a swr of 1.7:1 only
by having the end of the wire about 1 foot off the ground only 8 feet from
the base of the tower. The wire is tight and is tied to the ground 1 foot
from a chain link fence. The fence is 9 feet away from the tower.
When I checked the antenna, it received about 3 to 4 S units higher than a
dipole. Have not transmitted on it yet. The 1.7:1 swr is from 7.00 Mhz to
7.30 Mhz.
This does not sound right. There wire is too close to the tower, too sharp
of an angle and too flat of a swr.
Do I have of fluke of an antenna and should I shut up and just use it? Or is
this antenna not right and won?t do me diddily squat?
Thanks,
Kirk Mohror
K7EKM
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