Spiderbeam 160m Vertical Model 160-18-4WTH
13
160-18-4WTH Manual, Ver. 1.7 17-JULY-2021
2.6.2 Cutting the Wire and Ropes
It is up to you whether you choose to cut the wires and ropes before going to the field, or cut
them in the field. Due to their lengths, it is usually easier to cut them in the field.
Radiator Wire:
Cut 18m of CQ-532 wire
Top-Hat Wire:
Cut 4 pieces of DXW-UL wire, each 15m long
T.- H. Extension Ropes:
Cut 4 pieces of PVDF Monofil Line, each 20m long
Upper Guy Ropes:
Cut 4 pieces of 2mm Kevlar rope, each 17m long*
Lower Guy Ropes:
Cut 4 pieces of 2mm Kevlar rope, each 14m long*
*Prepare the Kevlar rope ends as described in APPENDIX B (5.2.)
2.7
Preparing the Radials
The Spiderbeam 160-18-4WTH was designed to be easy to install, using 16 ground-mounted
radials. Using any number between 8 and 24 will give rewarding results. If you use less,
performance will be reduced. If you use significantly more radials, the small gain in radiation
efficiency will be offset by losses in the coax due to higher SWR. We recommend 16 radials as
the “Sweet
Spot”
for this antenna.
As pointed out earlier, for more information on the deployment of radials and their 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.
2.7.1 Preparing the Radial Wires
The following instructions are based on the assumption that you are using 16 ground-mounted
radials as recommended. If you use more, or fewer, please adjust the numbers yourself.
The ground-mounted radials should each be between
⅛
and
¼
wavelength long (20 to 40m).
The length is not critical, but the number of radials is, with more being better.
Note: 16 radials
⅛
wavelength long is better than 8 radials ¼ wavelength long.
Usually, the length of each is determined by the space available to run the radials. 25 to 30m is
a good length to target.
Due to the length of the radial wires, this work is best performed in the field, directly
where the radials will be installed. You may choose to do this in advance, or do it later
during the installation.
You will need 320 to 640m of wire depending on the radial length, eight M6 cable solder
lugs, a crimping tool or pliers, a soldering iron 60w or greater, and liquid electrical tape.
