Many emergency services and local authorities are facing a dilemma. They need to improve their mobile voice and data communications but they cant afford the latest digital equipment.

Some are finding the answer in an innovative, low maintenance version of Simulcast being offered by Tait Electronics.

Called Tait Quasi-Sync, the analogue system uses clever technology to overcome the costly, regular maintenance normally required with Simulcast (the simultaneous transmission of the same frequency by many transmitters) to ensure audio is not distorted in areas where transmitter coverage overlaps.

In many cases Quasi-Sync control equipment can be laid over an organisations existing base station and antenna infrastructure, improving coverage and audio quality, and also enabling continued use of the existing fleet of radios.

"The cost-effectiveness of Quasi-Sync is one of its key benefits," says Tait Systems Product Manager, Jason Cox, "particularly for publicly funded organisations like municipalities."

"Quasi-Sync is also ideal for improving coverage, something many organisations are focussed on at the moment.

"Many customers are looking for improved in-building coverage, especially since September 11. Others are increasingly using portables rather than mobiles on their networks, some are centralising despatch facilities so they need single system coverage over a greater area, while many are simply looking to reduce the number of dead spots within their operational area.

"Then there are regulatory issues such as reducing interference, limiting transmitter power and antenna height, and the limited availability of channels all issues Quasi-Sync can overcome," says Jason.

In North America alone Tait has more than 20 Quasi-Sync systems in place.

The town of Oyster Bay, Long Island, is a typical Quasi-Sync customer. The municipality, which has 600 service vehicles, needed to upgrade its 30 year old mobile communications system.

"We needed a solution that would give us improved coverage," says Barry Bree, Assistant to the Commissioner. "But there was the unavailability of additional channels, not to mention the lack of budget to replace our entire mobile fleet."

The three-site, two-channel Quasi-Sync system provided by local Tait dealer, Telecom Communications, has provided coverage right across the municipalitys territory. "It was a smooth transition," says Mr Bree. "Not one of our 600 mobile or portable radios had to be touched by a technician in order to be integrated to the new system."

Being simulcast, the utilitys staff all have access to the same information, something that proved valuable as Hurricane Bonnie threatened Long Island just as the installation was being completed.

Barry Bree estimates that any other system providing comparable features would have been five times more expensive, and because Tait Quasi-Sync is virtually maintenance free, the savings will continue. "The money weve saved has allowed us to purchase additional new radios."

Quasi-Syncs ability to improve coverage within buildings is well illustrated by a system supplied to one of Switzerlands largest banks in central Zurich.

The bank has three buildings in the city centre and needed all-informed communications, particularly for security staff, within and between its offices.

A two-channel (voice and paging service) three-site Quasi-Sync system was installed. Each site has up to 14 antennas to ensure coverage in all floors, including the bank vaults.

One of Taits largest Quasi-Sync systems is in Southern Idaho where the police and fire services in Lincoln, Gooding, Jerome and Twin Falls counties, pooled resources to install four networks, with a total of 45 sites, to provide voice and data communications.

Adcom Engineering Consultant Joe Blaschka, who has 20 years experience with Simulcast, advised on the installation of the Southern Idaho system. "Its one of the best systems Ive seen. Its designed and manufactured to very high standards.

"The audio quality is very high, they have coverage in areas where it wasnt considered possible. The system is exceeding expectations and the users are real happy."

Further south in Sonoma County, California, 400 staff from three law enforcement agencies are using a five-channel, eight-site Tait Quasi-Sync system. Tait was able to make the upgrade for the countys 12 year old mobile communications system even more cost effective by overlaying the Quasi-Sync control equipment over its existing base station infrastructure.

"Law enforcement users can be a difficult group to impress but the staff are very pleased with the high audio quality of the Quasi-Sync system," said Joe Perez, County Assistant Communications Manager when the system was installed. "Its distinctly better than our previous system."

The relatively simple installation and modular nature of Tait Quasi-Sync also impressed Mr Perez. The modularity has proved important as the system has been expanded since the initial installation.

One of Taits most recent and highest profile Quasi-Sync customers is the Californian Highway Patrol, which is making use of the systems third party base station compatibility.

Tait Quasi-Sync is also ideal for train communications, and has been supplied to rail operators in UK, Malaysia and Canada, where it is used by SkyTrain and BC Rails line from Vancouver to St George.

How Tait Quasi-Sync Works

" Traditional Simulcast systems require regular maintenance because over time frequencies drift causing distorted audio in areas where transmitter coverage overlaps.

" Tait Quasi-Sync uses high stability oscillators to maintain a very stable transmitter frequency.

" Also Digital Signal Processing (DSP) based Line Equaliser Modules, routing audio to each transmitter, analyse the characteristics of a neighbouring transmitter and adapt their own signals to match.

" The result is that system servicing is virtually eliminated and users enjoy consistently high quality audio.

Quasi-Sync Coverage

Quasi-Sync can improve coverage in almost any situation.

Inside Buildings a bank in the compact business district of Zurich, Switzerland, has chosen a Quasi-Sync system and Tait portable radios to provide coverage in and between its three offices. The three sites each have up to 14 antennas to ensure coverage in all floors, including the bank vaults.

Urban Durban Metropolitan Council, South Africa, uses Tait Quasi-Sync systems with deliberate coverage overlap to ensure continued service for its 1000 radio users even if one site completely fails.

Regional the vast rural area of Botetourt County, Virginia uses a four-site Quasi-Sync system with channels for the sheriffs department, fire, rescue ambulance and school bus operation. Coverage is estimated at over 97% of the county, up from about 50% with the previous system.

Tait Quasi-Sync Benefits

" The usual Simulcast benefits of all-informed communications and excellent use of precious frequencies.

" The costly and regular servicing normally associated with Simulcast is virtually eliminated so users enjoy consistently high quality audio.

" Superior coverage as transmitter coverage neednt be limited to minimise overlap.

" An organisations existing mobile and portable terminal fleet can continue to be used, significantly reducing the cost of an upgrade.

" Compatible with most third party base stations, as well as Taits own high performing T800 base station range.

" Significantly less expensive than other systems offering comparable functionality and features.

Click here for more information on Quasi-Sync .