7
Antenna Installation
b. The rest of the interbay cable harness should naturally fall into place. Attach
the tees on the harness to the remaining radiators, as shown in
Figure 3
or
Figure 5
. For antennas with radomes, use the cable jumpers as shown.
c. Repeat step a for the bottommost connection.
The design of the antenna requires that the interbay feedline be about 50%
longer than the bay-to-bay spacing. To protect the slack cable from wind and
vibration damage, it must be wrapped and secured to the support pipe.
Figure 6. Installation of top and
bottom bays
CAUTION
To ensure proper antenna performance, the excess feedline must be
wrapped in a particular fashion, as shown in
Figure 7
on page 8. DO
NOT make a continuous spiral wrap around the pipe, as shown on the
left. Doing so will ruin the VSWR of the antenna.
d. Wrap and secure the interbay feedline cable as follows (
Figure 7
):
CAUTION
Do not put too much tension on the feedline; just make it snug.
(1) Between each pair of antenna bays, loosen the connectors at both ends
just enough to allow the cable to swivel as it is wrapped. This will
prevent kinking.
(2) Grasp the feedline in the middle and pull it gently out like a bowstring.
(3) Then wrap the middle around the pipe, resulting in the “two-way spiral”
shown in
Figure 7
.
(4) Fasten the feedline to the pipe with plastic ties or electrical tape. Do not
use metal ties, which can cut the line.
(5) Retighten the connectors at both ends.
(6) Repeat for each interbay section.
