PPC-1000 Rev.1.0
9 of 29
User
Manual
© DOK Ltd (Mm-wave Division of ELVA-1 ltd), 2005-2006. All rights reserved.
3
Site planning
3.1
General
Before the start of an installation a survey should be conducted of the proposed area of the
site(s). The survey personnel should be familiar with the details required to install the radio
system.
3.2
Equipment Checklist
The survey team may need the following equipment:
•
Binoculars or spyglass
•
Range-finder or GPS Navigation Device (to determine the exact link distance)
•
Mobile phones or walkie-talkie radios
3.3
Line of Sight (LOS)
The mm-wave wireless link requires Line-of-Sight for proper operation. It implies that no
obstacles like trees, buildings, chimneys have to be between the station sites. Moreover, no
obstacles should be situated in the vicinity of the signal propagation line (inside the first
Fresnel region).
Because the link distances are usually within 10 km so obstructions in the path can easily be
identified using binoculars.
The planning should include an investigation into future building plans that could block the
LOS path, and other long-term incremental obstructions such as growing trees. Intermittent
but regular obstructions such as flying aircrafts at a nearby airport should also be considered.
It is required to have absolutely no obstructions in front of the antenna in so called first
Fresnel zone. The minimum required clearance from obstacles is 60% of the first Fresnel zone.
Fresnel zones are a series of concentric ellipsoid areas surrounding the straight-line path
between two antennas. The first Fresnel zone is the area containing every point of which the
distance from the transmitter to any reflection point on the area and on to the receiver is half
a wavelength longer than the path of the direct signal. The radius of the Fresnel zone is
greatest at midpoint in the signal path.
Minimum Clearance for various bands is listed below (in meters):
Path Length
(km)
Minimum Clearance (meters)
Q-band
40.5-43.5
GHz
V-band
57-64 GHz
E-band
71-76/
81-86 GHz
W-band
92-95 GHz
1 km
1,4 m
1,1 m
1,0 m
0,9 m
2 km
2,0 m
1,6 m
1,4 m
1,2 m
5 km
3,2 m
2,5 m
2,3 m
1,9 m
10 km
4,5 m
3,5 m
3,1 m
2,7 m
