NOVA SCOTIA DEPARTMENT OF TRANSPORTATION VHF NETWORK
A component of the NSIMRS
Last updated October 2, 2021

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HISTORICAL PAGE

This page describes or depicts a system that no longer exists,
except that the repeaters at Hunters Mtn, Salem, Creignish, Savannah and Barr Settlement do remain and have been re-tasked for other uses. 

This system was a component of the NS Integrated Mobile Radio System in the 1980’s and 1990’s.  It was replaced in approximately 2000 when DOT migrated to the first trunked mobile radio system (TMR).  

23 of the 24 main sites had a DOT repeater, with the exception being Springfield, as indicated in the chart below.  All of those repeaters were removed soon after the migration to TMR.   Unlike other government services the DOT also had repeaters at several added NSIMRS sites which are listed in the chart as “Extra Site”.    These extra sites were added to accommodate the heavy winter communications needs in certain areas where there was more than one shed (local operation).    The sites and repeaters at French Lake (Savannah), Creignish, Hunters Mountain, Barr Settlement and Salem do remain and are now part of the VFD fire grid. 

DOT users would normally be tuned into the local repeater, and there was only one DOT repeater and channel for their use in that area (except in the cases where two or more repeaters were permanently linked, as described below).   Users would in most locations also be able to reach one or more other sites in the surrounding areas.  Users were provided with a guide and map to show which channel should be selected in any given area. 

Most DOT vehicles had radios with only a very few channels, good for their local repeater and perhaps one or two nearby other repeaters, plus the simplex channel.  Supervisory personnel would have the upgraded radio with a dial pad.   This would allow dialing-up more distant repeaters.   For example with this type of radio, a DOT user near Bridgewater would tune into the local Sherwood repeater and if he or she wanted to talk to Sydney, could dial the Rear Boisdale  DOT repeater, and talk through it.  The indicated dial-up code was used by a unit in one area in order to connect with a distant repeater.   The user brought up the local repeater and dialled the distant one by inputting the dial-up code.  The code was 500 plus the site number of the site desired.  In the example, the user in Bridgewater would dial 521 to activate the Rear Boisdale repeater.   To shut down this link, the code ** would be entered.

DOT users could also be connected to other department networks by dialing Shubie Radio (code 0), where an operator would set up a patch to the desired other network.

The unusual feature of the DOT system was that in most cases repeaters were arranged into pairs and possibly trios, hard-linked together.  For example, as seen on the chart below, the Middle Ohio and East Kemptville repeaters were linked so that one input of 149.20 would bring up both repeaters.   When one came up, the other would as well, whether the mobile transmitter could hit one or both sites.   The extra sites were later additions to the system, and it is not so well known in most cases how they fit into the simulcasting arrangement.   For example, the Savannah site is in the general vicinity of the two sites just mentioned and it is likely that it also was hard-linked with them so that in this case there would be a trio of repeaters coming up simultaneously.   That would also imply that the 150.53 Savannah repeater would also use the 149.20 input of the other two sites, rather than the 149.59 as used for the 150.53 repeater at Shubie.   This detail is however lost with time.

Note that repeaters on 150.605, 150.485 and 150.905 were all stand-alone, i.e. not simulcast with any other repeater.   150.905 was a late addition to the system, introduced in the Halifax region due to the heavy use of the already existing 150.605 repeater.  The shed serving the western part of HRM .. Halifax western suburbs and beyond to the county line continued on 150.605, whereas the Bedford/Sackville shed which served the eastern suburban area moved to the new 150.905 repeater.

The pairing or tripling of repeaters also meant that for dial-up purposes in linking the linked repeaters would have the same code.  For example Middle Ohio and E. Kemptville both used 501, with the 502 code not being used at all.  Savannah, if also linked, would also use the 501 code.

Tones are not confirmed, except that those in the area of Central Nova Scotia are all thought to have been 82.5. and in the Annapolis Valley and South Shore on 71.9.

DOT Simplex 149.89