FAQ, DOWNLOADS AND WHERE TO BUY
How does Comba’s CriticalPoint Antenna Monitoring System (AMS) work?
Comba’s CriticalPoint Antenna Monitoring System (AMS) works by combining an RFID signal with the LMR RF signal.The combined signal is then distributed to the service antennas. When the signal reaches an antenna being monitored, the RFID signal energizes the RFID antenna tag which in return sends a signal back to the Main Control Unit (MCU) that identiﬁes it and its health status. If for some reason the antenna does not transmit RFID data back to the systems MCU, it triggers an alarm for that individual antenna location. Up to 50 antennas can be monitored by a single MCU.
How reliable is RFID?
RFID is a time-tested technology and has been used around the world since 1973. It is widely used for many industries such as medical, manufacturing, retail, logistics and inventory tracking.
What RFID frequency band does the system utilize?
The Comba AMS system uses the UHF RFID frequency range (902-928MHz) which is part of the Amateur Radio Service and the Location and Monitoring Service (LMS). Operation of unlicensed Part 15 Devices is permitted between 902 and 928 MHz.
Will the RFID signal be subject to any interference, including 900MHz two-way radios/pagers?
As with any RF signal, interference is always a concern; however Comba’s CriticalPoint AMS system shouldn’t interfere with any 900MHz two-way radios. The AMS system utilizes very sharp ﬁlters around the RFID frequency to ensure any unwanted signals are rejected.
What components are involved with Comba’s CriticalPoint Antenna Monitoring System?
Each AMS system consists of one MCU (Master Controller Unit) and some number of Comba Addressable Service Antennas. Comba’s Addressable Service Antennas have the RFID tag pre-in-stalled, inside the radome cover.
How far can the RFID be from the Main Control Unit to receive the RFID signal.
For the Main Control Unit to successfully read the antenna’s RFID tag, the insertion loss between the MCU to any antenna shall be below 20dB.
Can this system be used for any type of public safety communication systems?
The Comba CriticalPoint AMS system can support frequencies from 380-960MHz. This includes UHF and 700/800MHz public safety communication networks.
If I have more than 50 antennas, can another system be used to monitor the remaining?
If you need more than 50 antennas, you could use two or more systems to support the number of antennas required. A block diagram below shows various conﬁgurations for a single BDA or Fiber DAS system.
What types of dry contact alarming does the system provide?
The Comba CriticalPoint AMS system provides two (2) dry contact alarm ports. They can report whether the Master Unit has failed and if there are any Failed Antennas (Overall).
Does the dry contact alarm indicate which antenna is malfunctioning?
No – the dry contact alarm only indicates that there is a problem somewhere in the antenna infrastructure system. To see which speciﬁc antenna is experiencing a problem, you log into the AMS system with an easy to use web based GUI.
Secondly – in the event that something changes the isolation (and causes oscillation) while the Fiber DAS is in use, the
CriticalPoint BDA will shut down and issue an alarm.
What is the cost of the Comba AMS system?
he AMS system cost is split between the cost of the Master Unit and Antennas or RFID tags. The Master Unit’s MSRP is $3,750 and the RFID equipped antenna’s MSRP range from $123.00 to $91.50 depending on the model.