User's Manual

Installing Fusion Wideband
Page 134 InterReach Fusion Wideband Installation, Operation, and Reference Manual
© 2015 TE Connectivity D-620616-0-20 Rev K • TECP-77-044 Issue 9 • March 2015
800/850 MHz Isolation Requirements
When deploying any RF system, give special attention to preventing receiver blocking or
desensitization by out-of-band transmitters. Typically, sharp filters in the receiver front-end will
reduce the interfering transmitters to tolerable levels. In select 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 interfering transmitters and receivers.
iDEN occupies spectrum at:
• 80
0 MHz
– Tx is 851–869
– Rx is 806–824
• 900 MHz
– T is 935–941
– Rx:896–902).
Th
e Cellular A and B carriers share a single 850 MHz block:
• Tx is 869–894
• Rx is 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 19 depicts
these nearly contiguous bands, with arrows indicating the interfering dow
nlink and receiving
uplink bands.
Figure 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 downlink-to-uplink
interference issues and provide adequate isolation (Figure 20 on page 135).
824 849 851 869 894 896 - 902
800/iDEN Uplink 850 Cellular Uplink 800/iDEN Downlink 850 Cellular Downlink 900/iDEN Uplink