User guide

45 Mbps Backhaul User Guide
Issue 3, December 2004 Page 99 of 113
Integrated
Antenna
28dBi Flat Plate
4 ft Parabolic
Dish
6ft Parabolic
Dish
BPSK ? 166.5 173.1 185.9 192.5
QPSK ? 162.8 169.4 182.2 188.8
QPSK 2/3 160.7 167.3 180.1 186.7
16QAM ? 156.1 162.7 175.5 182.1
16QAM ? 151.6 158.2 171.0 177.6
64QAM 2/3 146.2 152.8 165.6 172.2
64QAM ? 144.3 150.9 163.7 170.3
64QAM 7/8 139.6 146.2 159.0 165.6
Note: Gains are 23.5/28/34.4/37.7dBi and Cable Loss is 1.2dB for the External Antennas
Operating Mode
Static Link Budget (dB)
11.4 Deployment Considerations
The majority of radio links can be successfully deployed with the 45 Mbps Backhaul product. It should only be
necessary to use external antennas where the Link Budget Calculator indicates marginal performance for a
specific link. Examples of this would be where the link is heavily obscured by dense woodland on an NLOS
link or extremely long LOS links (>80km) over water.
The external antennas can be either dual-polarization (as the integrated antenna) or two single polarized
antennas can be used in a spatially diverse configuration. It is expected that the dual-polarization antennas
would normally be used to simplify the installation process; spatially diverse antennas may provide additional
fade margin on very long LOS links where there is evidence of correlation of the fading characteristics on
Vertical and Horizontal polarizations.
Dual polarization antennas (with a gain greater than the integrated antenna) are currently only available in
parabolic dish form.
11.5 Link Budget
This is increased by the additional gain of the external antenna(s) less the cable losses. The improvement in
link budget is indicated for a sample of the antennas when operating in BPSK 1/2 and 64QAM 7/8 modes.
Table 9 Static Link Budget for Various Antenna Options