User's Manual

AP Deployment Guide - System Release 1.4 Installation Prerequisites and Considerations
On-Ramp Wireless Incorporated 8 010-0006-00 Rev. F
6.3 Antenna System Sweep Testing. This value in dB is used when configuring the AP in the
EMS.
NOTE 2: All outdoor antenna cable connections must be weather sealed in an appropriate manner.
The table below shows the attenuation for common types of antenna lines.
Table 2. Attenuation at 2.4 GHz for Common Types of Antenna Cables
Model
Size
dB/25 ft
dB/50 ft
dB/100 ft
dB/150 ft
dB/200 ft
LMR-400
.40 inch
1.7
3.4
6.8
10.2
13.6
FSJ4-50B
½ inch
1.5
3.1
6.1
9.2
12.2
LDF4-50A
½ inch
.9
1.9
3.7
5.6
7.4
AVA5-50
⅞ inch
.5
1.0
1.9
2.9
3.8
3.2.3 GPS Antenna
The GPS antenna provides timing signals to the AP. It should be mounted so that it has a clear view
of the sky. A mounting location should be chosen that minimizes shadowing from trees or
structures.
NOTE: The GPS antenna should be mounted at least one meter away from the AP antenna to
minimize the chance of interference.
In normal operation, the AP requires GPS synchronization for precision timing of all nodes on the
network. To provide a reliable GPS signal, the AP has a built-in GPS receiver which requires an
externally connected GPS antenna. The GPS antenna cable is connected to a type-N female
connector on the AP.
Many different GPS antennas are available but On-Ramp Wireless recommends using the PCTEL GPS
antenna model GPSL1-TMG-SPI-40NCB for the following reasons:
1. The PCTEL GPS antenna has a low noise, high gain amplifier which is well-suited to address cable
attenuation when the GPS antenna mounting location requires a long length of cable. Up to a 20
dB cable loss is acceptable when using this high gain antenna.
2. The PCTEL GPS antenna provides integrated, onboard, lightning protection that minimizes the
need for a downstream, inline surge suppressor. The GPS antenna must be properly grounded.
See figure 4. If using an external surge suppressor, it must be a “DC pass-through” type.