User's Guide

Help Hot Line (U.S. only): 1-800-530-9960 7-33
D-620610-0-20 Rev B CONFIDENTIAL
Fusion Installation Procedures
these situations is to provide sufficient isolation by physically separating the interfer-
ing transmitters and receivers.
iDEN occupies spectrum at both 800 MHz and 900 MHz (Tx:806–825/Rx:851–870
and Tx:896–901/Rx:935–940), while the Cellular A and B carriers share a single 850
MHz block (Tx:869–894/Rx:824–849). The combination of these frequency bands,
800/900 MHz iDEN and 850 MHz Cellular, result in uplink (BTS receive) bands that
are adjacent to downlink (BTS transmit) bands. Figure 7-19 depicts these nearly con-
tiguous bands, with arrows indicating the interfering downlink and receiving uplink
bands.
Figure 7-19 800/850 MHz Spectrum
Installation of an in-building distributed antenna system (DAS) to provide coverage
for both 800/900 MHz iDEN and 850 MHz Cellular must account for these down-
link-to-uplink interference issues and provide adequate isolation.
LGC offers the following guidelines toward achieving the proper amount of isolation
when deploying LGC Wireless Unison DAS products.
Figure 7-20 Guideline for Unison RAU Antenna Placement
800 MHz iDEN Downlink and 850 MHz Cellular Uplink
A 2 MHz frequency gap (851 – 849 MHz) separates the 800 iDEN downlink and 850
Cellular uplink frequency bands. Because of this narrow spacing, 800 iDEN down-
link intermodulation products may fall within the 850 Cellular uplink band. In addi-
tion, 800 iDEN downlink signals near the lower edge of the band at 851 MHz may
850
850
850
Cellular
MHub
FSN-809019-1 RAU
FSN-8519-1 RAU
850
Cellular
RAU
850
EHub
Cellular