LTR Multi Net - San Rafael, California Police Department System

San Rafael, California Police Department System

After six years of use, a consultant was hired in May 1994 to evaluate perceived problems with the Police LTR MultiNet radio system. A committee was convened to review the consultant report and devise a strategy to resolve issues. A 1995 report to the Mayor and City Council found the city's Police LTR system could not be fixed, "...without redesigning or replacement of the E. F. Johnson system and/or its components." The report describes problems with the specific MultiNet system implemented by San Rafael Police including:

• As implemented, the trunked system had only two channels. While more channels were needed to resolve provisioning problems, the city did not have sufficient loading to qualify for licensing of additional channels under Federal Communications Commission (FCC) rules. Examples of provisioning problems included the FCC-required Morse code identifier would put one channel out of service, causing busy signals.
• The report suggests the system, as implemented, did not have adequate signal strength coverage of the hilly terrain around San Rafael. Users reported out-of-range indicators were displayed when at North Gate Mall, Point San Pedro east of the high school, Kaiser San Rafael Emergency Room, San Rafael Police locker room, Marin County Jail sally port, and the "canal area."
• Unit ID and emergency buttons did not perform reliably. Investigation was unable to reveal what caused this intermittent problem. In some cases, dispatchers got "ghost emergency button" signals: distress messages were received when the user had not pressed the emergency button, (called falsing). In another, a user pressed the emergency button but the button press was not received by dispatch.
• The system experienced intermittent reception among field units and at the dispatch console. In one instance, the report describes an officer at the scene of a call. A dispatcher makes an announcement: the officer's hand-held radio hears the call while the vehicle radio does not. It also cites an event where two officers were in a "potentially-deadly" situation and had to shout to one another because their radios could not communicate. Because calls to dispatch were sometimes not heard, there was friction between officers and dispatchers: officers thought the dispatcher was ignoring their call.
• The system was split into two transmitter coverage areas, requiring officers to remember to manually select an alternate channel when in certain parts of the city.
• The mutual aid patch allowed dispatch to set up a connection which allowed San Rafael officers to communicate with all other agencies in the county. The system patched a system and group setting on the trunked system to a 39 MHz base station. (All other agencies in the county used 39 MHz radio systems.) Users complained about long time constants (measured at 0.7 seconds) from the time an officer pressed the push-to-talk on a trunked radio until users on 39 MHz started to hear what they were saying. There were also problems with "lost transmissions." These problems caused messages to be repeated, which tied up channels and increased the potential for busy signals on the MultiNet system. The report says the patch system was abandoned, removing the department's mutual aid interoperability capability.
• Reliability problems with equipment were cited. In one example, a problem with mobile radios losing their programming put 25% of the police vehicle fleet out of service.
• A cumbersome servicing records system had to be established to track the equipment inventory. For example, when system software updates were required, city employees had to track which radio units had gotten the updates. A records system tracking all 97 radio units and their present software revision was established and maintained. The inventory system also tracked which units were at the shop and which ones were tagged as needing repair. These costs were absorbed by the Police Department.
• Ready and busy signal tones were adjusted by the radio set's volume control. This resulted in situations where users got a busy signal but could not hear it because the vehicle's siren was on or the patrol car windows were rolled down.

Estimated replacement cost for the system as of the 1995 report's date was $1,190,000. The committee recommended replacement of the trunked system with a conventional simulcast system.San Rafael now uses the MERA (Marin County) Motorola ASTRO SmartZone system and got rid of the LTR-Multinet system.