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APMxxxx Series User's Manual
14. Frequently Asked Questions (FAQ)
Q – Does the APM really evaluate each frequency individually?
A –
Yes.
Each frequency is broken down individually and the Tx Forward Power, Tx VSWR, Combiner
Insertion Loss, and Rx Level is displayed per-channel.
Q – Does the VSWR monitor function ignore nearby (12.5 KHz) off-frequency RF energy entering backwards
from other transmitting antennas (i.e. horizontally mounted antennas)
A –
Yes.
The VSWR, like the Tx Forward Power, is measured in a channelised bandwidth. The high
directivity of the APM directional coupler prevents Tx Forward Power from creating a Tx VSWR measurement
error also.
Q – What is the minimum channel spacing to maintain true channelisation?
A – The APM can discern and measure 12.5KHz channel separation between Tx channels.
Q – Channel bandwidth is established per channel during setup, and these could be mixed bandwidths (i.e.
25KHz Analogue, APCOP25 Phase1, TETRA, DMR, etc.) in a single combiner. Can these each be measured
individually?
A –
Yes.
Modulations and selected channel bandwidths can be mixed within a combiner with no issue as
modulation type is programmed by channel in the GUI. Channel bandwidth is automatically selected by the
modulation type chosen – except FM where several channel bandwidths are available.
Q – Are alarms logged for future reporting and analysis?
A –
Yes.
In firmware revision 1.92 and above, alarm events are stored in an Alarm Event Log which can be
viewed and downloaded as desired.
Q – Can alarms be sent to remote devices?
A –
Yes.
Alarm events can be sent via SMTP (Email), SNMP (Northbound) traps, APM relay outputs, or
(optional) SAM/CAM relay outputs to remote devices for monitoring. SNMP GET# Summary Alarms can also
be polled if desired.
Q – How is the VSWR calibrated to the antenna?
A – The APM accepts the cable loss of the tx feeder network and uses this to calculate the measured VSWR to
the top of the Tx antenna.
Q – Will calibration take into account different lengths, types, and losses of the cable?
A –
Yes.
The coupling loss, cable loss, and any variable losses will be compensated out during calibration.
Q – What is the minimum Tx forward power levels that can the monitored?
A – The APM will measure down to -10dBm and up to +60dBm without any changes.
Q – Can a PC file be created and/or saved of the APMs configuration?
A – Yes. A configuration file containing all of the APM's parameters relevant to a site may be prepared
beforehand and easily uploaded to an APM (locally or remotely via Ethernet port), simplifying the deployment
activities carried at a network site. This file is in easily editable text format for ease of use. In addition, multiple
configuration files can be stored within the APM and activated when desired to cater for network re-frequencying
transitions, different network operating configurations, or to back up APM configurations for site records, later
use, or convenient programming in the event of an APM unit being exchanged.
Q – Can the APM monitor the site's Base Rx frequencies?
A – Yes. Rx Monitoring and Tx-Rx Antenna Isolation testing can be performed and results displayed.
Asia Pacific | EMEA | Americas
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