User's Manual

The DC power takes a wire pair to the Outdoor Junction Box (OJB), and thence to each of the
Transceivers. The negative lead is grounded in the equipment room, inside the OJB and inside
the Transceiver.
Examples of voltage-drop calculations:
1. The standard cable shipped with the Transmitter is 25 feet of #18 AWG shielded twisted
pair annealed copper wire (Belden 3124A), which will have a 0.1 Volt drop at 600 mA.
Remember that the ground return is #18 in parallel with the #6 and some building
ground, so the return resistance is negligible.
2. If the installer splices on an additional 50 feet of #14 AWG twisted pair power cable to
the factory cable (to avoid changing the connector), the additional cable will have a
voltage drop of 0.1 Volts, so the total drop is 0.2 Volts.
Table 3-1: Wire resistance (annealed copper)
AWG
Ohms/100ft
24 2.567
22 1.614
20 1.015
18 0.6385
16 0.4016
14 0.2525
3.1.4 Transmitter
The radiated power from the antenna is 1 Watt (30 dBm). This maximum power is set by FCC
regulations. The user must not add any amplifiers or make any other changes that will exceed
this wattage.
The omnidirectional antenna gain is 13 dBi. Assuming the transmitter is located a short
distance from the antenna, so that the loss in the coaxial cable is negligible, the output of the
transmitter must be no more than 17 dBm.
The omnidirectional antenna radiates 360 degrees (hence the name) horizontally, and about 5
degrees vertically.
The antenna is designed so that when the mechanical mounting is true vertical, there is an
electrical downtilt of one degree. That makes the radiated pattern 1.5 degrees above and 3.5
degrees below horizontal. An inexpensive tool to help establish true vertical is a level made for
fence posts, which has two spirit/liquid levels at right angles.
The spectrum at the input to the transmitter will look like Figure 3-5.
June 2003 Page 3-4