Quoting Richard Cariello <rcariello@si.rr.com>:
> I am going to fly a Wire Vertical for 160 meters. The wire will be
> held up with the use of a Balloon. before. My question is which
> antenna length should I use,1/4 1/2 or 5/8 wave lenght.
Rich,
Since you have a ground system to reference, the best and most stable balloon
supported vertical IMHO would be the 1/4 wave, or even better yet a 3/8 wave
(185') series tuned to resonance with a capacitor. A 1/2 or 5/8 may not be
exactly vertical all the time (serious pattern distortions), although having a
lower TOA (if they are perfectly vertical) are more difficult to feed. There
is a slight gain on the 1/2 and 5/8 wave but it may not be worth the effort.
Obviously the lift weight of a 1/2 wave is twice as much as a 1/4 wave. But
remember that the winds aloft can be considerably higher than on the ground.
Some balloon radio users, especially those with access to advertising blimps,
use fishing line to guy agains the wind effects.
In a contest such as CQ WW 160 you are also looking for a good Q rate from
close in stations where the higher signal arrival angle may be important. The
5/8 wave certainly would theoretically out perform all others on long haul.
However, the ambiguities with TOA's and arrival angles on 160 changing from
day to day and hour to hour, the 5/8 wave may be disapointing.
In the early 80's I used (from time to time) a 300 foot insulated tower when I
lived at the radio station location. This tower was 5/8 wave over a AM
station ground. My location was on an islet at the entrance to the harbor
surrounded by salt water. (Connected to land by a small road fill.) My corner
fed Delta loop at this location was a much beter performer especially on
receive. (No room for Beverages)
I expected miracles with the 5/8 wave vertical on 160 but this antenna was a
disappointment months of comparisons.
Herb Schoenbohm, KV4FZ
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