This is the insulator I have been working with. I have one other method
I wish to try now. This one I think will be best. Element is very solid
all directions. Also more than enough spacing from the boom.
The antenna shown below is made with 1/2 inch elements and left over
parts from broken antennas and from over the years.. Didn't want to
waste any of the new material in the testing stage. Yes some of the
elements are not in proper horizontal alignment. All the nuts had been
tightened by hand only just to get a quick test of the match. I bumped
thigs around a bit when I quickly laid it on the ground to get these
pictures.
length is 4980mm from reflector to last driven element or
16.33 feet. At 10 feet above ground the match was very good 1.2 SWR on
the analyzer at 144.200. At 143.900 it was 1.1. I had cut the driven
element a bit long for fine tuning, so looks like it should be very
good at higher mounting and a small amount of driven element
trimming. The grey box is a outdoor electrical outlet enclosure.
Will use a different one on final antennas. Matching section made with
RG-11. Bend is to tight due to the enclosure. Different box will
allow more available length of matching section outside of box to allow
less bend.
The tests I made here fall very close to claimed
gain. I feel mine will be even closer when testing can be
done a greater height above ground. Now if I just had 4 of them done
and ready to go on the tower !!
DK7ZB design 9 elements, 5 meter boom, 12.5 DBd gain, F/B
30.38db, Beamwidth 33 deg
These designs can be found at the website of the designer DK7ZB .
