NOVA SCOTIA INTEGRATED MOBILE RADIO SYSTEM (NSIMRS)
The Historical View

Last updated Oct 4 2021

The initials NSIMRS are commonly pronounced as an acronym "nizmirz" or "nismirs", and in this page the assumption in syntax is that
you will be pronouncing it as a word, without "the" preceding it.

This page and the linked pages associated with it refer to NSIMRS as it existed and functioned in the 1980's and 1990's.
It was replaced by the first NS trunk system in and around the year 2000.   Some components of NSIMRS still exist today, and along
with other components added, the term NSIMRS is still used.   This page is NOT about the modern NSIMRS.


NSIMRS was a set of VHF repeater sites operated by the province of Nova Scotia and located throughout the province, and in full operation throughout the 1980's and 1990's.   It provided the radio  communications infrastructure required by mobile units belonging to the province, and as well by associated public service agencies, including the ambulance service and volunteer fire departments and other volunteer services such as ground search and rescue and emergency measures management.  It was intended for joint use by the province, the RCMP, local police, EMO, GSAR and fire departments.  This system was substantially reduced when the first trunked mobile radio system came into service in and around the year 2000.   Most of the networks on NSIMRS were decommissioned and equipment removed soon after the changeover.   All of the tower sites in NSIMRS still exist today but with a much different capability than what is described here.

The system was originally made up of 24 provincially owned repeater sites, as shown on this
map.   Eight additional sites were added over time to meet the specific needs of the Department of Transportation ("highways").   The individual sites were linked by a microwave system so that any site could be connected with any other, as described father down this page.     On the map the lines shown are the routes of the microwave system that linked the sites between each other and back to Shubie Radio, RCMP Telecoms, and to certain central offices and hospitals. 

 H Division of the RCMP had repeaters on all or almost all of the NSIMRS towers, so can be regarded as a lodger user, but they also had many other repeaters throughout the province. 

NSIMRS was made up of six specialized networks.  Specific pages with frequency and tone information plus in some cases maps are linked from here.

Note that in October 2021 these individual pages that I have resurrected from the past, are being revised, but should remain available while this is happening.

This chart lists the twenty-four sites plus eight additional sites used originally only by the Department of Transportation.   Repeater output frequencies are shown for five of the networks.  Specific pages linked above have more detail. The Municipal Police Network, not shown here, had only one frequency (153.59 MHz).  Additionally the RCMP was a lodger user of the network, and used several other sites in addition to the those listed.

Site # Rptr Site Area Served
1 Middle Ohio Shelburne
2 East Kemptville Yarmouth
3 North Range Corner Digby County
4 DND Annapolis
5 Springfield Springfield
6 Garland Kings County
7 Liverpool Queens County
8 Sherwood Lunenburg County
9 Willow Hill West Hants
10 Hammonds Plains Halifax
11 Jerusalem Hill Musquodoboit Hbr
12 Marinette Sheet Harbour
13 Kirkhill Parrsboro
14 Sugarloaf Cumberland County
15 Nuttby Mtn Colchester County
16 McLellan's Mtn New Glasgow
17 Cochrane Hill Sherbrooke
18 Fairmont Antigonish
19 Lundy Guysborough
20 Oban St. Peter's
21 Rear Boisdale Sydney
22 Kiltarlity Mtn Inverness County
23 Cape Smokey Ingonish
24 Money Point Cape North
? Shubie Milford DOT shed
? Hammonds Plains? Sackville DOT shed
? Italy Cross RCMP Bridgewater area sheds
? Barr Settlement Noel DOT shed
? Salem Amherst shed
? Savannah (French Lake) Pubnico area shed
? Creignish Port Hastings area shed
? Hunter's Mtn Baddeck area shed

Note that the sites appearing without site numbers are extra sites or frequencies
on existing sites, that were added to serve only the Dept of Transportation, due
mostly to radio traffic congestion in the winter months, with the need to establish separate
radio channels.

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 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.

Connection between networks (patching) was possible through Shubie Radio, the central control centre for the system, operated at that time by the Department of Natural Resources.  Any unit with tone signal equipment could dial 0 to contact the Shubie 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, and patches to the landline telephone system.

The lodger RCMP network could also be linked to components of NSIMRS by way of a link that would be established between Shubie Radio and RCMP Telecoms.

The IMRS began to be phased out in 2000 with the advent of the Nova Scotia Trunked Mobile Radio System.  For several years many of the repeaters stayed in place, as of course it took time and money to remove the equipment.  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, which is now referred to as the EMO network remains available for volunteer use and as an emergency backup to the trunk system.