Rope ANT for 144 MHz - does it work?
|I began with
47 elements long DL6WU yagi. The picture shows the
antenna shortly after finishing. The antenna is about 1.5
mtrs above the ground.
||This is the
detail of one end of the antenna. This device is crucial.
You need very precisely set the tension in both ropes to
the same level. Otherwise the antenna will screw.
antenna is very small and light when coiled.
The elements are alluminium pipes diameter 6 mm. Inner diameter is 4 mm.
tension must be applied to strain the antenna. Even so,
it will always have a little slackness.
account the given azimuth and -3dB beamwidth the antenna
should cover mainly PA.
from the first 24hrs contest were a disappointment. It
looks that the main lobe splitted into two, and two more
lobes came into being at about 40 degrees.
It was caused by an excessive slackness of the antenna.
I shortened the antenna to 30 elements and use now even higher tension to strain it. It improved the pattern significantly.
|But I still
missed the answer: does't it actually work?
The answer is in comparison of the two 24hrs contests. Left is without using the rope antenna, the right is with it.
All the other conditions of the contests were the same.
It is obvious that the antenna yielded a bunch of additional QSOs, mainly from squares JO30, JO31, JO32.
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