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Messenger (Center Support) Line
The center-T support top 0.371” hole is used for the attachment
of a UV resistant support line - sometimes called a “Messenger
Line” that can be strung above the antenna wire and is used to
provide support for the antenna wire and feedline. The use of the
messenger line, which is strongly recommended, will reduce
stress on the element wires and keep the antenna from stretching
over time, which will change its resonant frequency.
Determine the required length for the messenger line. Ideally, it should attach to the same structure used for
the dipole legs, only above them, forming at least a 30 degree angle between the dipole ends and the
messenger line which allows some sway room for the rope in the trees.
The ends of the rope should be cauterized with a small flame to prevent the rope braid from fraying. Allow
some slack in the dipole legs to allow for swaying of the trees.
After determining the proper length needed, form a loop at the mid-point of the
messenger rope. Push this loop through the center-T support top hole where you want
the center of the dipole positioned, then pull the rest of the rope through the loop.
Coax Cable Strain Relief Option when using a Messenger Line
Any dipole using a Messenger Line or other means of mounting where the coax cable hangs down a Coax
Cable Strain Relief is strongly recommended. When the coax cable is connected to the Balun, it can be heavy
and pull slightly (or completely) out of a PL-259 (especially when windy and the coax is subjected to waving
around from weather). By using the Coax Cable Strain Relief, you are taking the strain off of the PL-259.
If you are mounting the dipole to a telescoping pole, the coax can be taped to the pole to avoid strain on the
PL-259. There are two optional Coax Cable Supports available from DX Engineering. DXE-CSR8X-1 if
using RG-8X sized coax as feedline (https://www.dxengineering.com/parts/dxe-csr8x-1) -or- DXE-CSR213-
1(https://www.dxengineering.com/parts/dxe-csr213-1) if using RG-213 sized coax cable as feedline.
The instructions for assembly and mounting the Coax Cable Strain Relief to the Balun Mounting Bracket are
included with the Coax Cable Strain Relief kit (they can also be seen on-line at DX Engineering.com).
Other Support Options
If you have the room and can install three telescoping poles, use a longer one for the center to install the
Balun Mounting Bracket and for the dipole ends two other telescoping pole as well.
The Balun Mounting Bracket can be attached to the pole with a DXE ECLS clamp. Refer to the DX
Engineering website to determine the ECLS Clamp size that fits the center pole that is used. There is a chart
that will help you determine the size ECLS clamp you require.
See: https://www.dxengineering.com/search?N=part-type%3Astudded-
clamps&SortBy=BestKeywordMatch&SortOrder=Ascending&keyword=ecls%20clamp
Use the two fender washers (#10 x .6875, 11/16”
OD Fender Washers 0.37” thick) on each
side of the upper hole in the mounting
bracket. Install the threaded portion of the
ECLS clamp through the washers and tighten in
place. You can then install the assembly on your
pole and tighten the ECLS worm drive in place. The
lower portion of the Balun was held to the fiberglass pole by securing the feedline coax to the pole with
electrical tape.