NOVA SCOTIA INTEGRATED MOBILE RADIO SYSTEM
Last updated May 8, 2009

© 2009, MARITIMES SCANNING SITE, all rights reserved (Hobbyists are welcome to download and use this information but not to publish elsewhere)

The NSIMRS is a network of VHF repeater sites operated by the province of Nova Scotia and located throughout the province,  intended primarily  for provincial use but also for the use of local emergency service providers such as police and fire departments.  This system was most active during the 1980's and 90's but since then has been partially dismantled as it has been replaced to a great extent by the 800 MHz NS Trunked Mobile Radio System.

This page and the pages describing the individual networks are based on information gathered at the time the NSIMRS was active.   Sources include definitive official provincial documentation issued to users, on scanner frequency lists, and on my own monitoring activities during the 1980's and 90's.   These pages are to some extent speculative and incomplete, and further information from anyone with further accurate information is very much sought.   Please email any comments, correction and additions to marscan1@canada.com

The system was originally made up of 24 provincially owned repeater sites, as shown on this map .   The NSIMRS was made up of seven specialized networks:

• Department of Natural Resources (output frequencies near 163 MHz)

• Department of Transportation (frequencies near 150 MHz)

• Hospital/Ambulance (frequencies near 159 MHz)

• EMO and miscl departments [GSS network] (frequencies near 143 MHz) 

• Nova Scotia Fire grid (frequencies near 152 MHz)

• Municipal Police network (153.59 MHz)

• RCMP network (frequencies in the 155 MHz range)

This chart lists the twenty-four sites plus additional sites used only by the Department of Transportation.   Repeater output frequencies are shown for five of the networks.  The Municipal Police Network, not shown here, had only one frequency.  Additionally the RCMP was a lodger user of the network, and used several other sites in addition to the those listed.

The users of any one network could access directly only that one network.  They could use the local repeater in the normal way, but if suitably equipped with tone-signalling equipment, could dial up distant repeaters in their own network from one end of the province to the other.  Distant repeaters were called up by dialing the specific repeater number.  For example a DNR mobile unit in the Halifax area could access the local repeater at Hammonds Plains on 163.05 and then dial 221 to access the Sydney area (200 for DNR plus 21 for the Rear Boisdale repeater). It is unknown what numbers were used for the extra DOT repeater sites. Additionally there were offices equipped with tone-accessed radios, so that field units could call the head office, or ambulances could call hospitals.  The mobile would dial them just as if they were dialing a distant repeater, and the base units would have numbers made up of the network prefix and then a number from 25 upwards.  For example a central office for DNR had the number 225. These base units would not have to constantly monitor their local frequency, but rather could answer when signaled specifically.

Note that the RCMP network was not part of the linking system just described but the RCMP dispatch centres could link to Shubie Radio and through it to the other networks.

Connection between networks (patching) was possible through Shubie Radio, the central control centre for the system, operated by the Department of Natural Resources.  Any unit with tone signal equipment could dial 0 to contact the operator and if desired request a patch to another network.  This was not something heard often, but occasionally ambulances, rural fire trucks, vehicle compliance officers, and RCMP units could be heard patched to other networks.  Shubie Radio also provided a dispatch and information service for users.  It still remains available to the remaining networks for radio checks and information look-up, and possibly also phone patches, but it no longer dispatches any provincial government departments.   (Shubie Radio remains active on the NS Trunked Mobile Radio System for similar services)

The IMRS began to be phased out in 2000.  By at least 2004 the DNR and Ambulance networks were completely gone.  The Fire Grid remains in service as in many cases it is used for dispatching rural departments or for their operations. Similarly the General Service network might remain for some time until all volunteer units, particularly search and rescue organizations, have converted to the 800 MHz trunk.    Some parts of the Municipal Police network remain in service, notably in the Annapolis Valley and New Glasgow area where the few remaining departments still intercommunicate.  Several repeaters of the DOT network remain: In January 2009 it is thought that of the DOT network, only these repeaters are still in operation: Barr Settlement, Savannah, Hunters Mtn, Salem and Creignish, but transferred for use by other agencies, possibly as part of the fire network.  I have it on good authority that some of the former RCMP repeaters remain in service, perhaps for use by auxiliary citizen patrols or perhaps as backups in urban areas. 

Expanded information (charts, maps, description) on the individual networks: