User's Manual

pulsAR radio Operator’s Manual
3-6
3.2.4 Antenna Installation
NOTICE
The antennas for the pulsAR radios must be professionally installed on permanent structures for
outdoor operations. The installer is responsible for ensuring that the limits imposed by the applicable
regulatory agency (FCC, IC, or CE) with regard to Maximum Effective Isotropic Radiated Power
(EIRP) and Maximum Permissible Exposure (MPE) are not violated. These limits are described in
the following sections.
The pulsAR radio is typically attached to a pole (with the clamp provided) with the antenna
connectors facing up. For optimum performance the radio must be mounted in close proximity to the
antenna with a cable run typically under 2 meters (6 feet). Afar carries several antennas for operation
at either 900 MHz or 2.4 GHz as shown below:
Band Antenna Type Gain AFAR Model Number
Omni-directional 5 dBi ATO-0905
900 MHz
Dish Reflector 15 dBi ATD-0915
Omni-directional 9 dBi ATO-2409
2.4 GHz
Dish Reflector 24 dBi ATD-2424
Antennas at each end of the link must be mounted such that they have the same polarization, and
directional antennas must be carefully oriented towards each other. The choice of polarization
(horizontal vs. vertical) is, in many cases, arbitrary. However, many potentially interfering signals
are polarized vertically and an excellent means of reducing their effect is to mount the system
antennas for horizontal polarization. Of those antennas listed above, the directional antennas can be
mounted for horizontal or vertical polarization, while the omni-directional antennas can only be
mounted for vertical polarization.
Proper grounding of the antenna is important for lightning protection as well as to prevent electrical
noise interference from other sources. The antenna should be mounted to a mast or tower that is well
grounded to Earth. Use weatherproof connectors in all outdoor couplings. Also use the “coax-seal
tape” (included with the radio) to further weatherproof outdoor connections.
If the coaxial cable between the radio and antenna exceeds 10 ft (3 m) you may also want to install a
lightning arrestor device at the N type connector of the radio (Afar part no SUP-0205). For short
coaxial cable lengths you do not need a RF lightning arrestor device.
3.2.5 Antenna Alignment
When mounting the high gain antenna (24 dBi), the proper antenna alignment is extremely important
since the beam-width of the antenna is very narrow. Once you perform a rough alignment and the
link is in operation, you can use the “monitor-link” and “antenna-alignment-aid” commands. Type:
> monitor-link