• Obstruction of the router antenna view of the cellular base station tower 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
antenna view of the base station. Additionally, unshielded (and even shielded cables in some cases) may
radiate signals that interfere with RF signal reception.
• It is recommended that all cellular antennas for the IR1101 are oriented vertically to ensure polarization
match. While polarization of the signal may change as it is reflected from obstructions, when the view
is unobstructed - vertical polarization is optimal.
• When installing the IR1101 with or without the Expansion Modules, the following note is important:
Note
: 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 Main and Aux cellular
antennas are physically separated from the IR1101 chassis by a minimum of 5 feet (1.5 meters). This note
only affects P-LTE-xx receiver operation in Band 5 in a narrow 875 MHz frequency range. No significant
effect on the P-LTE-xx cellular Band 5 receiver has been measured when antennas are separated from the
chassis by more than 5 feet (1.5 meters). This note 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.
• For optimal MIMO performance, space cellular Main and Aux antennas apart by at least 17 inches (43
cm). At the lowest LTE frequency of 700 MHz, 17 inches represents 1 wavelength. Spacing of half (or
0.5) wavelength or 8.5 inch (22.5cm) results in good MIMO performance.
• Spacing Main and Aux LTE antennas less than 8.5 inches may result in significantly reduced MIMO
performance.
• Spacing antennas too close to each other (e.g. 3 inches) results in antennas significantly detuning from
their original designed performance due to antenna coupling.
• Wherever possible, mount the IR1101 router with the pluggable LTE module and 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 will degrade the wireless radio signals. Install the
IR1101, 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.
• The density of the materials used in a building's construction determines the number of walls the signal
must pass through while still maintaining adequate coverage. Consider the following before choosing
the location for installing the antenna:
• Paper and vinyl walls have very little effect on signal penetration.
• Solid and precast concrete walls limit signal penetration to one or two walls without degradation of
coverage.
• Concrete and wood block walls limit signal penetration to three or four walls.
• A signal can penetrate five or six walls constructed of drywall or wood.
• A thick metal wall or wire-mesh stucco wall causes signals to reflect back and causes poor
penetration.
• Avoid mounting the antenna next to a column or vertical support that could create a shadow zone and
reduce the coverage area.
• Keep the antenna away from reflective metal objects such as heating and air-conditioning ducts, large
ceiling trusses, building superstructures, and major power cabling runs. If necessary, use an extension
cable to relocate the antenna away from these obstructions.
IR1101 Industrial Integrated Services Router Hardware Installation Guide
44
Antenna Selection and Installation
Antenna Installation Best Practices
