24
Cisco Aironet 1520, 1130, 1240 Series Wireless Mesh Access Points, Design and Deployment Guide, Release 6.0
OL-20213-01
Mesh Network Components
shows one of the recommend installations of an outdoor AP1520.
Figure 12
Outdoor Pole-top Installation of a Mesh Access Point
Maximum Ratio Combining
AP1520 radios have a much higher transmit power, better receiver sensitivity and broader outdoor
temperature range as compared to AP1510 and AP1505 mesh access points.
•
The 5GHz radio (802.11a) is a Single in Single Out (SISO) architecture and the 2.4GHz radio
(802.11 b/g) is 1x3 Single in Multiple Out (SIMO) architecture.
•
The 2.4 GHz radio has one transmitter and three receivers. Output power is configurable to 5 levels.
With its 3 receivers enabling maximum-ratio combining (MRC), this radio has better sensitivity and
range than a typical SISO 802.11b/g radio for OFDM rates.
When operating with data rates higher that 12 Mb/s, you can increase gain on a 2.4-GHz radio to 2.7 dB
by adding two antennas and to 4.5 dB, by adding three antennas.
1
2.4-GHz antenna (Tx/Rx)
3
Fiber-optic connection
2
5-GHz antenna (Tx/Rx)
4
4.9-GHz antenna (Tx/Rx)
1
Outdoor light control
3
6-AWG copper grounding wire
2
Streetlight power tap adapter
231524
1
2
3
Table 7
RX Sensitivities and MRC Gain
Typical sensitivity (dBM)
MRC gain
Modulation
Rate
One antenna
Two antennas
MRC
Three antennas
MRC
Two antennas
Three antenna
1
-92.0
-92.0
-92.0
0.0
0.0
2
-91.0
-91.0
-91.0
0.0
0.0
5.5
-90.3
-90.3
-90.3
0.0
0.0
11
-90.0
-90.0
-90.0
0.0
0.0