First bottle
is original. Second bottle has removed upper part. The first original
bottle is inserted to the second one with removed upper
part. First and second bottles are fastened with wide scotch.
Then the part inserted in the third bottle with removed
upper part and so on. It is very desirable
to tie each part of the form with a strong synthetic rope,
stretched inside the bottles. This synthetic rope serves
for installation of the antenna. The helical antenna may
hang up with the rope. I did form in 5 meter length from
these plastic bottles.
While my experiments with helical antennas I used
the bottle to make a form as a temporary experimental one
with short lifetime. However, one experimented helical antenna
with the bottle form was live during seven years. The antenna
was installed in the closed balcony and when it was removed
the antenna still was fully operated...
Operation
of Helical Antenna at Open Air
Helical antenna does not like open air. It is high
Q antenna and any disturbing effect on the antenna, whether
it is mechanical or atmospheric, can lead to complete loss
of the antenna's performance on the desired band. Therefore,
helical antenna should be protected from any disturbing
influences.
What may happen
with helical antenna placed outdoor? As
result of exposure to the helical antenna of snow, rain,
low and high temperatures, the main resonance frequency
of the helical antenna may move outside the operation range
of the antenna. Snow, fog, moisture from rain that covered
the antenna may be lowered Q of the antenna and result of
it the antenna would be not operated on the second or third
harmonic and main resonant frequency may be moved unpredictably.
Helical antennas should be protected from such atmospheric
influences. Better place the helical antenna inside- to
the attic or balcony closed by windows. If the helical antenna
should work at outdoor condition use design of the antenna
that not exposed much by the atmospheric conditions. Follow
by simple rules that placed below.
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