© Microhard Systems Inc. Confidential 104
Direct human contact with
the antenna is potentially
unhealthy when a P900 is
generating RF energy.
Always ensure that the P900
equipment is powered down
(off) during installation.
7.0 Installation
7.2.2 Coaxial Cable
The following types of coaxial cable are recommended and suitable for most applica-
tions (followed by loss at 900MHz, in dB, per 100 feet):
LMR 195 (10.7)
LMR 400 (3.9)
LMR 600 (2.5)
For a typical application, LMR 400 may be suitable. Where a long cable run is re-
quired - and in particular within networks where there is not a lot of margin available
- a cable with lower loss should be considered.
When installing cable, care must be taken to not physically damage it (be particularly
careful with respect to not kinking it at any time) and to secure it properly. Care must
also be taken to affix the connectors properly - using the proper crimping tools -
and to weatherproof them.
7.2.3 Surge Arrestors
The most effective protection against lightning-induced damage is to install two light-
ning surge arrestors: one at the antenna, the other at the interface with the equip-
ment. The surge arrestor grounding system should be fully interconnected with the
transmission tower and power grounding systems to form a single, fully integrated
ground circuit. Typically, both ports on surge arrestors are N-type female.
7.2.4 External Filter
Although the Pico Series is capable of filtering-out RF noise in most environments,
there are circumstances that require external filtering. Paging towers and cellular
base stations in close proximity to the P900’s antenna can desensitize the receiver.
Microhard Systems Inc.’s external cavity filter eliminates this problem. The filter has
two N-female connectors and should be connected inline at the interface to the RF
equipment.
To comply with FCC
regulations, the maximum
EIRP must not exceed
36dBm.
A l l i n s t a l l a t i o n ,
maintenance, and removal
work must be done in
accordance with applicable
codes.
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