Spiderbeam 160m Vertical Model 160-18-4WTH
6
160-18-4WTH Manual, Ver. 1.7 17-JULY-2021
The more wires used for the top-hat, the shorter the wires must be and the better the radiation
symmetry of the omni-directional radiation pattern.
The lower the angle of the top-hat wires to the pole, the longer they must be. Every attempt
should be made to keep the angle of the slope of these wires as high as possible - the closer to
being horizontal, the better the antenna will work. This is accomplished by placing the ground
stakes supporting the top-hat wires as far away from the pole as possible (typically 25m).
Ground characteristics at the installation QTH are a given and cannot be easily improved. You
have to accept what you have and realize that this is one of the reasons that we cannot specify
an exact length for the top-hat wires. These wires usually must be adjusted to compensate for
variances in ground characteristics.
The ground-mounted radial network consists typically of 16 radials. In portable installations, as
little as 8 ground mounted radials has been shown to give excellent results, but more is better.
For more information on the deployment of radials and its impact on performance, we recommend
reading the excellent article by Rudy Severns (N6LF), in the December 2010 issue of QST. This
article summarizes the information put forth by Rudy in a series of 7 articles for QEX magazine.
1.3
Material Description:
It is of utmost importance to keep the material used near the top of the pole as lightweight as
possible, yet strong enough to endure the severe winter conditions that prevail during prime low-
band activity.
The Spiderbeam 160-18-4WTH is built with high quality, lightweight but strong material:
The vertical radiator wire is made of Spiderbeam CQ-532 wire. This is AWG-18 stranded
Copper-weld wire, with ultraviolet-resistant polyethylene insulation. The wire itself has
1.1 mm diameter, with an OD of 2.2mm. Its breaking strength is 50 kg.
The top-hat wire is made of DXW-UL wire. This is stranded copper wire, interwoven with
multiple strands of Kevlar rope, which gives it extra strength. It has ultraviolet-resistant
polyethylene insulation.
The top-hat guy rope is made of PVDF Monofil line. This 1mm diameter line is ultraviolet-
resistant and very durable. Its light weight and good resistance to icing make it optimal for
this use. This looks like normal fishing line, but is much higher quality.
The insulators are also made of lightweight polyethylene, are ultraviolet-resistant and very
strong. Despite the low RF current in the top-hat wires, expect very high voltage. As a
consequence, we use 2
“
Spiderbeam special insulators
”
in each top-hat line. For high
power, use 3 insulators in each Top-Hat line.
Do not substitute other insulators.
The Spiderbeam Radial
Connection Box is purpose built for connecting the antenna’s c
oax,
radiator, and radials. It is also available as a separate option for other use.
