Ok, that makes sense Bob:
27 feet (or maybe slightly more) is the top of the mast right now. I
would LOVE to put another tower section on, but right now cannot afford
it.
As far as performance, both the tribander and the wire seem to do pretty
well. I have plenty of dx on both of them
Thanks for the ideas and the link
TIM
W8TAH
On 2/21/2016 1:10 PM, Robert Harmon wrote:
Tim,
The first thing I see is that the tri-bander needs to be higher to get
reasonable DX performance. From what you described the tri-bander is at
22 feet high and
a 6M beam at 27 feet. Is 27 feet the highest point on the mast ? I
would give the
tri bander priority on height and get it up as high as you can. With the
sunspot cycle declining 10M and 15M will be have poor conditions and 20M
will be the best band out of the three for a few years untill condx
start ramping up again, At 22 feet high the take off
angle is almost straight up on 20 meters and would be very poor for DX.
If the height could be raised to 35 feet then you would have a half
wavelength on 20 which would be about the
lowest height for DXing. I think your wire dipole at 40 feet would be a
better DX performer than the tribander unless you can raise the
tribander. Here is a good article from the ARRL
on antenna heights to give you some more insight on this.
https://www.arrl.org/files/file/antplnr.pdf
Bob
K6UJ
On 2/20/16 2:10 PM, Timothy A. Holmes wrote:
Hi Folks:
Spent part of the day outside today re-rigging the balun on my
ladderline fed doublet. Got me thinking about my antenna system and
the work that needs done to it.
The system is as follows:
135' doublet at ~40 feet fed with ladder line to a 4:1 balun and then
coax to the radio
6m, 3 element beam -- fed with some sort of coax (Unknown type, Old)
about 27 feet up on the tower
9 element 2m beam at about 24 feet on the tower -- fed with some sort
of old unknown coax
3 element Tri-bander at 22 feet on the tower fed with (again) some
sort of old unknown coax
I have all the equipment in the shack bonded together, but that system
needs to be reworked, as does the outside ground as right now it is a
hunk of old water pipe pounded a foot or so into the ground outside my
window, connected to everything with braid.
The rotor is connected to the controller with two separate runs of
cable (need to be replaced) because thats what I had available. as
well the Uclamps on the top of the rotor need replaced
THe rotor is old, given to me by a friend, I dont remember the make
and model of it, and Im too tired to go pull it off the tower to check
-- LOL
the tower itself is 2 sections of tower -- made of what looks like
1"OD tubing with horizontal cross braces welded to the vertical legs.
Each face is about 14 inches across. again, it as given to me. Its
mounted on a home made tilt over base which is spiked into the ground
with 3, 3' spikes made from ground rod (copper over steel)
the cable run to the base of the tower is about 30 feet or so and
tower top is 20 feet + Mast -- so longest runs should be short of 60
feet.
I am pretty sure I have the wrong sorts of coax on each antenna, as I
grabbed whatever fit and hooked it up.
I do have a roll (maybe 100 feet or a little more ) of what appears to
be 5/8" air dialectric hard line that I reclaimed from an upgraded
cable TV installation years ago
My main interests are contesting, DXing and a little bit of VHF weak
signals work.
Now for the questions. What do I need to fix / replace and what do I
need to do it with. What recommendations do you have for cables,
cable types, mounting systems etc etc etc -- I really want / need to
improve my antenna system.
Secondly -- I would like to work on improving my low angle performance
on 10, 15, 20 for DXing -- Im beginning modeling a wire vertical --
any suggestions.
The biggest problem with all of this is I am unemployed, so money is
in short supply, raising the tower is not an option right now unless
someone knows someone who has tower they want to donate to a worthy
cause -- LOL
Ok -- thanks much -- any input/ideas that you have or any questions
you might have, please let me know
TIM
W8TAH
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