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This article first appeared in the September 2000 issue of Monitoring Times.
If you read the advertising put out by companies that manufacture trunked radio systems, you'd think they always perform easily and reliably for the public safety agencies that purchase them. In many cases the systems do work well, however there are always glitches in any complex system. Sometimes the glitches can be minor, such as an occasional missed transmission, and sometimes they can be life-threatening. Orange County, California Back in July officials in Orange County, California, announced they would stop the roll-out of their $80 million trunked radio system due to a significant number of failures, several of which put lives at risk. A new Motorola 800 MHz digital ASTRO system is being tested by police departments in Irvine and Tustin, who have reported significant gaps in coverage, garbled messages, and even radios that drain vehicle batteries. On several occasions officers have been unable to call for assistance, their transmissions being blocked or otherwise prevented from reaching the dispatcher. Some of the problems have been blamed on inadequate coverage from transmission towers and some on the nature of 800 MHz signals. Older radio systems operating in the 400 MHz band have better penetration into buildings and underground garages and are not subject to nearby interference from cellular telephone towers, which also operate in the 800 MHz range.While the bugs are being worked out you should still be able to hear Main Dispatch in conventional mode on 460.4250 MHz and 507.1125 MHz. The new Orange County system is supposed to replace a patchwork of incompatible radio networks operated by different agencies within the county. Six primary transmitters and 21 remote sites will use more than 80 frequencies, including: 856.2125, 856.4625, 856.7125, 856.9625, 857.2125, 857.4625, 857.7125, 857.9625, 858.2125, 858.4625, 858.7125, 858.9625, 859.2125, 859.4625, 859.7125, 859.9625, 860.2125, 860.4625, 860.7125, 860.9625, 866.100, 866.125, 866.150, 866.175, 866.200, 866.325, 866.350, 866.375, 866.400, 866.425, 866.450, 866.600, 866.625, 866.650, 866.675, 866.700, 866.825, 866.850, 866.875, 866.900, 866.925, 867.100, 867.125, 867.150, 867.175, 867.200, 867.325, 867.35, 867.375, 867.400, 867.425, 867.600, 867.625, 867.650, 867.675, 867.700, 867.825, 867.850, 867.875, 867.900, 867.925, 868.100, 868.125, 868.150, 868.175, 868.200, 868.325, 868.350, 868.375, 868.400, 868.425, 868.600, 868.625, 868.650, 868.675, 868.700, 868.825, 868.85, 868.875, and 868.925 MHz. In the meantime, Orange County Fire continues to operate three older Motorola Type I analog systems, each with half a dozen or so channels. Countywide activity occurs on 856.2125, 856.7125, 857.2125, 857.7125, 858.2125, 859.2125, and 860.2125 MHz. 860.9625 MHz may occasionally be in use as a talk-around channel (direct mobile-to-mobile rather than through the repeater). Suggested fleet maps for TrunkTracker users including Block 0 with size code 2 and Block 4 with size code 13. Some reported talkgroups are:
Paramedics operate on 462.950 MHz. The North County system operates on 856.9625, 857.4625, 858.4625, 859.4625, 859.9625, and 860.4625 MHz, covering the cities of Anaheim, Brea, Buena Park, Fullerton, Garden Grove, Orange, and Stanton. For TrunkTrackers, Block 0 should have a size code of 2 and Block 4 a size code of 13. The 400-series talkgroup is also in use in this system:
Central County operations occur on 856.4625, 857.9625, 858.7125, 858.9625, 859.7125, and 860.7125 MHz. This system includes Costa Mesa, Fountain Valley, Huntington Beach, Newport, and Santa Ana. TrunkTrackers should use a size code of 11 in Block 2 and a size code of 13 in Block 4.
State of Florida The Motorola 800 MHz ASTRO digital trunked SmartZone system installed for State of Florida is probably the most notorious example of trunked radio system problems. The network is geographically large, covering most of the southern part of the state. The primary user is the Florida Highway Patrol, although it is shared with numerous other state and Federal agencies. The system apparently worked well during Hurricane Georges in September 1998 when the state quickly added some emergency talkgroups that allowed different agencies to coordinate their efforts. They also made use of the telephone interconnect feature to patch messages directly through to officer's radios from telephones in the state capitol and elsewhere. More recently, however, as more and more users began making use of the system, trouble came in the form of blocked transmissions and significant gaps in coverage. Even worse, parts of the system would "freeze" or crash, rendering radios useless and almost always leaving officers at risk. Problems were bad enough that the state task force recently awarded the statewide radio project to Com-Net Ericsson, a competitor of Motorola's. The system will reportedly not change to EDACS (Enhanced Digital Access Communications System), but it will be a challenge to regain the confidence of the system's users. Since the system uses digital voice coding even trunked scanner listeners are not able to hear the voice portion of the conversation, but the frequencies in use are: 853.9625, 854.0125, 854.0375, 854.0875, 854.1125, 854.1375, 854.1875, 854.2375, 854.2625, 854.2875, 866.4500, 866.9375, 866.9625, 866.9750, 866.9875, 867.4375, 867.4500, 867.4750, 867.9375, 867.9500, 867.9625, 867.9750, 867.9875, 868.4500, 868.4625, 868.4750, 868.4875, 868.9375, 868.9500, 868.9625, 868.9750 and 868.9875MHz. Metro-Dade County, Florida Motorola isn't the only vendor facing unhappy customers. Just a few years ago Ericsson paid $3 million in fines for contractual non-performance as it struggled to fix problems with their $43 million Metro-Dade, Florida, 800 MHz EDACS network. Digital signal processing delays, gaps in coverage, poor reception, and lousy audio quality topped the list of problems in a system that was reportedly designed to handle more than 30 million transmissions per month. In October 1998 the county finally accepted the system. More than 17,000 radios went into operation, served through seven repeater sites. Forty operating channels are shared across several independent systems that serve different user groups. The local government and fire system operates on 866.1125, 866.3625, 866.6125, 866.8625, 867.1375, 867.3875, 867.6625, 867.9125, 868.2625, 868.5125, 866.1375, 866.3875, 866.6375, 866.8875, 867.2875, 867.5375, 868.1125, 868.3625, 868.6125, and 868.8625 MHz. Fire operations use Agency codes 00, 01, 02, and 03. In particular,
The primary public safety system operates on 866.0375, 866.2875, 866.7625, 867.0625, 867.4125, 867.7875, 868.1375, 868.3875, 868.6375, 868.8875, 866.0625, 866.3125, 866.5625, 866.8125, 867.1125, 867.3625, 867.5625, 867.8125, 868.1625 and 868.4125 MHz.
Kansas City, Missouri In 1998, four Kansas City firefighters trapped in a burning house found their EDACS radios wouldn't work as they called for help. They eventually escaped, but the incident brought to a head problems that had been unresolved with the system. After a lot of finger-pointing the city finally admitted they had not done their part to effectively specify the performance they needed, and spent more than $8 million to upgrade the original $18 million system. The frequencies are, in Logical Channel Number (LCN) order: 856.2125, 857.2125, 858.2125, 859.2125, 860.2125, 856.4625, 857.4625, 858.4625, 859.4625, 860.4625, 856.2625, 857.2625, 858.2625, 859.2625, 860.2625, 856.7375, 857.7375, 858.7375, 859.7375, 860.7375, 856.4375, 857.4375, 858.4375, 859.4375 and 860.4375 MHz. Kansas City Fire Ground Channels
As an aside, North Kansas City has a rather unusual setup. They have five frequencies and use Motorola equipment, but they're not actually trunking. Each frequency is dedicated to a specific purpose, just like a conventional system. There is no control channel.
There are a few cars equipped with EDACS radios to allow officers to communicate with the Kansas City police. Tallahassee, Florida The City of Tallahassee, Florida, is trying to do things right. They are continuing to expand their $13 million Motorola Type II trunked radio system, now including Leon County and the Leon County Sheriff's Office. Prior to the additions, the original 13 voice channels were shown to be performing well with a traffic load averaging between 25,000 and 45,000 transmissions per day with an average dispatch time of 5 seconds. This is about a third of the maximum capability of the system. Five voice channels were added to support Leon County and the Leon County Sheriff's Office, which experience an average of 11,000 daily transmissions. One additional channel would be added to handle the Florida A&M Police Department, who has also requested to use the 800 MHz system. Assigned frequencies are 851.0000, 854.9625, 855.4625,855.9625, 856.4625, 856.7125, 856.9625, 857.2125, 857.4625, 857.7125, 857.9625, 858.2125, 858.4625, 858.7125, 858.9625, 859.2125, 859.4625, 859.7125, 859.9625, 860.2125, 860.4625, 860.7125, and 860.9625 MHz. That's all for this month. Keep the frequency lists and talkgroup charts coming to dan@signalharbor.com, and check my website at www.signalharbor.com for more information. Until next month, happy monitoring! |
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