NOVA SCOTIA FIRE GRID
Last updated Oct 2, 2021

THIS IS A HISTORICAL PAGE.    THIS NETWORK STILL OPERATES WITH CHANGES.
THIS PAGE DESCRIBES IT AS IT WAS, INCLUDING FEATURES THAT NO LONGER EXIST.

Officially this was the Volunteer Fire Department network on NSIMRS, but it was more commony referred to as the “Fire Grid”.   The fire grid was a system of vhf repeaters in Nova Scotia that was intended to be a local and regional wide-area resource for volunteer fire departments.   Not only would it allow individual departments to have reliable coverage over their complete service area, it would also allow intercommunication with other departments in the region at a level higher than that allowed by the simplex 153.83 frequency.    In addition, the repeater could be used as a paging transmitter, and allow for multi-department page-outs.   Finally, because these sites were linked together, any user with a suitably equipped radio could dial-up a central dispatch site for patching to other services or to allow communications throughout the province.    This system was a component of the NS Integrated Mobile Radio System, which has largely been replaced by the 800 MHz NS Trunked Mobile Radio System.  This component has been left in place as it is used on a daily basis in parts of the province for volunteer fire department dispatch and operations.  Some sites are virtually unused today.  There never was a time when all departments used this network, but they certainly could have if they wished.  Many or most departments continued to use their VHF frequencies and towers for paging and communications. 

Each of the 24 main NSIMRS sites had a fire repeater installed.  Note that there were 11 different channels.    The output frequencies were in the 151 to 152 range and with inputs in the 154 range.  By all accounts it was very difficult to find a set of frequencies to use in this network due to the already-existing allocations to individual departments.    This led to the peculiar situation of having an output frequency being paired with different input frequencies, depending on the location in the province.   As well a search of fire department frequencies in those days would show that the frequencies used in the grid were also used individually by departments, albeit in different areas of the province.

The chart below shows for historical purposes the dial-up codes for each repeater.  These would be used by a user who wanted to contact a unit outside of the local repeater area.  This linking system is now discontinued, and all repeaters are now standalone.    There have been other features introduced since 2000 but as this is an historic article, these will not be covered here.

Please note that several repeaters remaining from the former Department of Transportation system are now considered to be parts of the fire grid, and as well several new repeaters have been added at other sites.  The repeater at Marinette was moved in or around 2017 to New Chester, a site that did not formerly exist.  

 A map of the grid appears here

PROVINCIAL SIMPLEX (MUTUAL AID) 153.83

Note that the channel numbers vary with the output and input frequencies, not with the CTCSS tone. 
In some cases the same output frequency is used in two different channels, but with a different input frequency.

FORMER DEPT OF TRANSPORTATION REPEATERS NOW CONSIDERED TO BE PART OF THE FIRE GRID REPEATER SYSTEM.   THESE MAY OR MAY NOT ACTUALLY BE IN USE.   The Barr Settlement frequency is integrated into the East Hants fire radio plan.   The Salem site seems to be in use by at least the Truemanville VFD.