De-Icer Installation (if applicable)
20
CAUTION
To prevent electrical short-circuiting, secure all cables to minimize wind-
induced motion and chafing against edges of system or tower compo-
nents.
CAUTION
It is important that you ground
both
the tower junction box and the con-
trol box, as shown in
Figure 11
on page 21.
CAUTION
When testing the thermostat in step k, be sure to disconnect one or both
thermostat leads before taking resistance readings. Otherwise, readings
may be affected by other components.
CAUTION
The resistance readings in Tables 3 through 6 are for the Shively-sup-
plied portion of the systems only, and do not take into account any long
run of cable to the tower and up to the antenna.
CAUTION
An improperly installed de-icer can overheat and damage your antenna.
Installation procedure
De-icer installation
a. Install the main de-icer harness with its bay junction boxes as shown in the
installation drawing and
Figure 11
on page 21.
b. Connect the leads from each bay de-icer to the main harness in that bay’s
junction box as shown in
Figure 12
on page 22. Secure any slack in these
cables to the feedline with tie-wraps to avoid wind damage.
c. Furnish a tower junction box as shown schematically in
Figure 11
to connect
the antenna’s de-icer harness to the main power.
NOTE
Shively recommends the use of shielded braided polyethylene-covered
wire or rubber-sheathed flexible metal conduit or rigid conduit and
weather-tight fittings at all junctions.
d. Using tie-wraps, secure the entire length of the de-icer harness to the RF
feedline at about 24" (60 cm) intervals. Run the ten-foot pigtail along a
feedline mount to the tower junction box and secure it to the mount and the
tower.
e. Furnish a main control box as shown schematically in
Figure 13
on page 23.
NOTE
The wire size must account for the total current draw of the cable run to
the antenna and the de-icer system itself.
f. Run a power cable from the control box in the building to the tower junction
box and connect it to the de-icer harness pigtail(s) in the tower junction box.
