Motorola BT100 - Manual (Page 46)

Installation 5-3
BT100 Installation and Operation Manual
Pedestal Installation
Pedestal installation is similar to the aerial installation with the exception of temperature and
mounting procedure. In an aerial installation, the cable and amplifier are subject to the same
temperature. In contrast, pedestal installation provides a stable temperature environment for
the buried cable while subjecting the elevated amplifier to higher temperatures. The
ADU/QADU, if installed, functions the same as in an aerial installation, and does not require
further attention. See Section 3, “Amplifier Setup,” Amplifier Level Control for additional
information.
Manual thermal compensation provided by the TDU can be inaccurate and result in signal level
changes with ambient temperature change. One approach to this problem is to select the least
amount of cable setting (low) on the TDU. This results in minimal gain change with
temperature. A preferred approach is to install a JXP-TH*C thermal attenuator while operating
the BT100 in the manual mode.
To mount the BT100 on a pedestal:
1 Remove two 5/16-inch messenger clamp bolts located on the long sides of the BT100
housing.
2 Locate the two 5/16-inch holes (Figure 2-7) eleven inches center-to-center cast in the lower
housing.
3 Use the two 5/16-inch bolts to install the BT100 to the pre-drilled pedestal mounting plate
and torque to 10 to 12 ft-lbs.
Grounding the BT100
The BT100 housing requires a good earth ground to function properly. You can establish a good
earth ground by one of the following methods.
For aerial metal-strand installations — the metal strand clamp normally provides adequate
grounding. However, if additional grounding is needed, you may attach a wire from earth
ground to a 5/16 x 24 bolt that is tightly secured to one of the pedestal mounting holes on the
bottom of the housing base.
For pedestal installations — the BT100 should be adequately grounded by routine mounting to
the pedestal. However, if additional grounding is needed, attach a ground wire to a 5/16 x 24
bolt and tighten it into one of the strand clamp holes.