PROJECT COMPLETION ANNOUNCEMENT:
OBJECTIVE
ACG Systems was tasked with installing a radio network on Brightline’s new rail route between Cocoa and Orlando, FL for their Maintenance of Way channel. This was comprised of four simplex base stations, each about 15 miles apart.
LIMITATIONS / CONSTRAINTS
The original communications system was limited to a maintenance office operator communicating with handheld/mobile radios within the range of each base station (simplex only, and handheld/mobile radios could only communicate with each other locally within the range that two handheld/mobile radios have.) Once installed, the result was that handheld/mobile radio users would need to convey their message to the base station operator at the maintenance office. That operator would then need to broadcast the message back out through the other base stations in order for all other distant radio users to hear the initial message. This required an operator to always monitor and forward radio traffic when needed. Naturally, this was very inefficient.
SCOPE
When Brightline hired a new track maintenance group, they requested ACG Systems to engineer a solution eliminating the need for an operator to constantly monitor radio traffic and to allow handheld/mobile radio users to communicate with any other radio user anywhere along the rail route.
ACG APPROACH
ACG was awarded Brightline’s project to upgrade the radio communications to a voting/simulcast system using Icom equipment, which included:
- Upgrading the common simplex frequency used at the four base stations to a common repeater frequency pair.
- Upgrading the four base station radios to repeaters, linking them together via fiber, and syncing to GPS and NTP timing. This precise timing helps synchronize the modulation of the repeaters’ transmitted signals to help reduce RF interference in the signal overlap areas between the repeaters.
- Assurance that each call is picked up by the closest repeater and retransmits, in sync, with all four repeaters simultaneously, providing continuous coverage along the railway between the Cocoa and Orlando stations.
- Installation of duplexers at each repeater site were installed to isolate the receiver from the transmitter within each repeater thus allowing them to share the same existing antenna at each of the four sites.
ACG SOLUTION
How It Works: The handheld/mobile radio transmits, and the repeater receiving the strongest signal then simultaneously transmits the call from all four repeaters, which allows all other handhelds/mobiles within range to receive the call.
- The updated system enables any handheld/mobile radio user to communicate directly with another anywhere along the tracks between stations in Cocoa and Orlando.
- Calls can be monitored and responded to, if needed, from any of Brightline’s Avtec consoles located in Miami, West Palm Beach, and Orlando.
We were able to leverage the existing antenna system and fiber infrastructure to help reduce the overall upgrade cost in providing this robust solution that has shown to truly provide end-to-end coverage all along the railway – even using handheld radios.
Joe Williamson, Director of System Engineering, ACG Systems