Cisco Catalyst IR1800 Rugged Series, Руководство по установке оборудования

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antennas of these systems are located close to each other. Interference may also occur when antennas are in
close proximity to cable clutter or other sources of radio interference.
Follow these guidelines to ensure the best possible performance:
• When you use cellular antennas such as 3G UMTS, 4G/LTE, 4G/LTEA (LTE Advanced), and 5G NR
FR1 with a modular router and a pluggable module, try to mount the antennas a certain distance away
from the router. For example, in indoor deployments, an appropriate extension cable and antenna stand
can be utilized. For outdoor installations, choose a suitable outdoor antenna, and mount it away from
obstructions such that the antennas have a direct view of the cellular tower. The antenna's performance,
and therefore that of the router, will not be optimal if mounted directly on a pluggable module. Primary
reasons for possible degradation of performance include:
• The router antenna's view of the cellular base station tower being obstructed by Ethernet cables,
power cables, USB cables, and walls.
• Possible coupling of digital noise from inside the router to the antenna when unshielded Ethernet
cables are used.
• Keep antennas away from electrical and signal cable clutter. Metal conductors inside cables may block
an antenna's view of the base station. Additionally, unshielded (and even shielded cables in some cases)
may radiate signals that interfere with RF signal reception.
• We recommend that all the cellular antennas for the IR1800 are oriented vertically to ensure polarization
match. While polarization of the signal may change because it is reflected from obstructions, when the
view is unobstructed, vertical polarization is optimal.
When cellular FDD Band 5 is deployed with 3G WCDMA, 4G/LTE, or 4G/LTEA C/A, such as with P-LTE-US
or P-LTEA-EA pluggable modules on certain carriers, ensure that both the Main and Aux cellular antennas
are physically separated from the IR1800 chassis by a minimum of 5 feet (1.5 meters). This is applicable only
to the P-LTE-xx receiver operation in Band 5 in a narrow 875-MHz frequency range. No significant effect
has been observed on the P-LTE-xx cellular Band 5 receiver when antennas are separated from the chassis
by more than 5 feet (1.5 meters). This information does not apply when the receive signal does not overlap
875 MHz, such as when operating on other bands, or other frequencies within FDD Band 5. Note
• For optimal MIMO performance, set the cellular Main and Aux antennas apart by at least 20 inches (50
cm). At the lowest LTE frequency of 617 MHz, 20 inches represents 1 wavelength. Spacing of half (or
0.5) wavelength or 10 inch (25 cm) results in good MIMO performance.
• Setting the Main and Aux LTE antennas less than 10 inches apart may result in significantly reduced
MIMO performance.
• Placing the antennas too close to each other, for example 3 inches, results in the antennas significantly
detuning from their original designed performance because of antenna coupling.
• Wherever possible, mount the IR1800 router with the pluggable LTE module and the antenna where the
cellular base station or tower are within sight and without physical obstructions. Barriers along the line
of sight between the router and the local base station degrades the wireless radio signals. Install the
IR1800, pluggable modules, and antennas above floor level in office environments, or near the ceiling,
for better performance because most obstructions tend to be near the floor level.
Cisco Catalyst IR1800 Rugged Series Router Hardware Installation Guide
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Antenna Selection and Installation
Antenna Installation Best Practices