Unison Component Installation Procedures
7-24
InterReach Unison Installation, Operation, and Reference Manual
CONFIDENTIAL
D-620003-0-20 Rev J
cases, the interferers may occupy a frequency band that is directly adjacent to the
receiving band and cannot be adequately rejected by filtering. The only recourse in
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 800
MHz block (Tx:869–894/Rx:824–849). The combination of these frequency bands,
800/900 MHz iDEN and 800 MHz Cellular, result in uplink (BTS receive) bands that
are adjacent to downlink (BTS transmit) bands. Figure 7-3 depicts these nearly con-
tiguous bands, with arrows indicating the interfering downlink and receiving uplink
bands.
Figure 7-3
800 MHz Spectrum
Installation of an in-building distributed antenna system (DAS) to provide coverage
for both 800/900 MHz iDEN and 800 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 7-4
Guideline for Unison RAU Antenna Placement
800 MHz iDEN Downlink & 800 MHz Cellular Uplink
A 2 MHz frequency gap (851 – 849 MHz) separates the 800 iDEN downlink and 800
Cellular uplink frequency bands. Because of this narrow spacing, 800 iDEN down-
