Copyright RF Industries Pty Ltd 2014. Subject to change without notice.
rfiwireless.com.au
3
Copyright RF Industries Pty Ltd 2014. Subject to change without notice.
rfiwireless.com.au
2
The Antenna System Monitor can be used to measure and monitor
the following network performance parameters for up to 80 channels
that may be distributed across up to four (or more) separate combiner
systems;
• Transmitters’ Forward Power
(from -50dBm to +60dBm per channel)
• Antenna VSWR
(from 1:1 to 20:1 per channel)
• Receive (RSSI) levels
(from -110dBm to -50dBm per channel)
• System Transmit-to-Receive Isolation
These measurements are logged and stored in non-volatile memory, with historical performance data available for review
or downloading. The following data from logging can be shown graphically or downloaded as a CSV text file;
• Transmitter Power (Max/Min)
• Transmitter Channel Utilisation (%)
• Antenna VSWR (Max/Min)
• Receive Level (Max/Min)
• Receive Channel Utilisation (%)
• Alarm Event Log
Overview
Antenna System Monitoring
The measurement, monitoring and reporting of the performance of wireless network infrastructure has come a long
way over past years. Many modern base station repeaters provide integrated measurement capabilities, but the
use of combining and/or isolators in the RF path from the base station transmitter output to the antenna isolates the
repeaters from reporting most problems that may occur within the combiner and antenna sub-systems.
The inherent inaccuracies of using in-line wattmeters (or sampler detectors) to measure forward and reverse power
on multi-carrier systems, due to the carriers’ ever-changing random phase relationships, results in random and
inaccurate measurement values. Connecting such devices into multi-carrier locations within the system often
introduces intermodulation into the system, risking optimum network performance.
The use of an Antenna SystemMonitor (ASM) facilitates the per-channel measurement of each transmitter’s forward
and reverse power, the system’s transmit-to-receive isolation, receive signal levels and much, much more….
Once installed, the ASM is non-intrusive to the network and continuously monitors
the RF performance of the site “24x7” on a detailed per-channel basis. This
enables coverage-impacting issues at a site to be detected, measured and
reported as soon as they occur – often before network users experience them.
The extensive testing capability of the ASM allows most Periodic Maintenance
Inspections (PMIs) to be performed without the usual site outages and their impact
on network availability.
Optional Site Alarm Modules (SAMs) may be connected to an ASM, adding the
monitoring of temperature, analogue voltages and digital inputs - in addition to
providing multiple relay outputs - to enhance an ASM’s functionality.
Interconnection
Network Site Monitoring
When installed at a network site, an ASM can measure base station transmitter output powers and antenna
VSWRs, and receive levels from network terminals, remote RTUs or adjacent network sites – all on a per-
channel basis. In addition, the site’s transmit-to-receive system isolation can be measured and benchmarked.
The programming of alarm thresholds values can be set based on network user’s coverage requirements,
coverage overlap from adjoining sites, and maintenance obligations. Alarm events can notify maintenance
personnel of a developing fault. Subject to the severity of the fault’s impact on a user, an appropriate response
can be actioned.
For example, if an antenna VSWR alarm is configured to trigger when it reaches 1.8:1, a decision can be
made on the priority of response required. If the event occurred at 2am on Saturday morning, and the site
benefitted from coverage overlap from surrounding sites, a response decision might be to schedule the
maintenance activity for 9am Monday morning as the level of impact may be determined as ‘minor’. This
may save an after-hours callout for a rigger and after-hours duty technician – potentially saving thousands
of dollars. However, the VSWR could then be monitored and any further degradation could still result in an
escalation in response if required.
Alternatively, if a fault showed a “low” base station Tx output level, but a good antenna VSWR, then the
response might be to send the duty technician with base station spares – rather than taking a rigger and a
crew with a spare antenna. Another significant saving in response costs.
The Antenna System Monitor is ideally suited to a wide range of applications supporting wireless networks.
Its capabilities cater for analogue, digital, FDMA and TDMA modulations. An integral webserver in the ASM
provides a user-friendly
Graphical User Interface
(GUI) that allows the programming of channel information
and alarm thresholds on a per-channel basis, site and customer details, and other ASM operating parameters.
The relay, SNMP, Email, Manager Messages and SAM alarm interfaces can be implemented to provide various
alarm notifications, and the GUI provides configuration programming and status monitoring compatibility for
computer, tablet, mobile phone and mainframe users. Current measurement values and alarm statuses can
also be viewed locally or remotely.
RX
REV
FWD
Power
Link Cable
TXCombiner
BASE
STATIONS
Coupler
ETHERNET
RX1
RX2
RX3
TX1
TX2
TX3
ASM
RX
Antenna
TX
Antenna
(OPTIONAL) SAM(s)
RMC
Preselector
Applications
