Government Radio Network (Australia)

The Government Radio Network (or GRN) is one single Australia-wide radio system. Some states in Australia run a GRN in that state (eg. SAGRN in South Australia, NSWGRN in NSW etc). It is a trunked radio network usually using Motorola SmartZone. In essence this is a system of interconnected (by microwave links) repeater sites, mobile (vehicle mounted), portable and static radio transceivers used within Australia for radio communications.

This system is used by almost all Australian emergency services (police, fire, ambulance) along with some private companies.

GRNs can be a mix of analog and digital. Eg. on the SAGRN, only Police (SAPOL) and Fisheries Dept use digital (and encrypted) radios while all other users use analog (unencrypted) radios.

Frequencies are allocated dynamically to each "talk group" (group of connected radios) as required and are only activated in areas ("cells") which contain radios belonging to that "talk group".

The frequencies used are licensed by the ACMA and are outside of the Citizen's band, and as such are relatively secure from casual interference, although of course they can be monitored by scanners.

The South Australian Country Fire Service, Metropolitan Fire Service, Ambulance Service, State Emergency Service, Department Of Fisheries, Volunteer Marine Rescue, Department Of Transport, St John Ambulance and several other government agencies use GRN radios.In addition, the NSW Rural Fire Service operates on the GRN in some areas.

the basis of the SAGRN is the sharing of frequencies, for example on a conventional scanner, you may hear a bus depot talking about a problem, next you may here a ambulance talking to a hospital. this is why to monitor the network, you will require a trunk or trunking scanner.

The network also has Multi-Agency talk groups which allow the different services to be able to talk to each other, at mass emergency's, major events, or whenever is needed. hence even those using digital and encryption can switch to a Multi Agency TG and the digital and encryption is disabled to allow them to talk to non digital users.

This is not Possible on other talk groups as each agency is supplied its on talk groups and channels.

The Current network equipment is supplied by Motorola, and consists of the following, Base Radios, Motorola mcs 2000 mk 2 and mk 3, Motorola xtl 2500, Motorola w7, Motorola w3 and Motorola rch3000portables, Motorola mts 2000 mk3, Motorola xts3000 mk3 Motorola ats2500 mk3.

The GRN also has a Telephone inter-connect feature, where phone calls can be made, all services except SAPOL, can only dial certain numbers pre-programmed into their radios.SAPOL, have unlimited dialing and can dial any number they wish, this how ever is a expensive feature, as a 5min call is charged by airtime and connection, and number of times the PTT(Push to Talk) button is pressed. a 6min call will cost around 55$

The GRN also has a remote kill feature, where if a radio is lost or stolen, a kill signal can be sent to the radio, which if it is on will instantly kill the radio, or if the radio is off, waits until it is turned on then sends the signal, this turns a radio into a expensive paper weight, and can only be fixed by Motorola, and then questions will be asked where you got the radio, and why do you have this radio.

the GRN also has a state-wide paging network, where messages can be sent and received almost simultaneousness, allowing a rapid response of crews. the pagers are supplied by Samsung and are model SFA-170. they are enabled so even if the pager is in silent, or vibrate, and regardless of what tone settings the user has set if a pager receives a message containing *urgmsg* or *cfsres* the pager will activate on the alert tone 7 the loudest high pitch tone on the pager.

at this point in time the contract is due to expire between Motorola and Telstra in this year 2008, it is anticipated the new networkwill be in place and updated by around 2010/2012.

it is also unclear at this point in time, if Motorola will continue to supply the equipment. If Motorola will be no longer be supplying equipment, a new vendor will have to be found through a tender, for supply, and maintenance of the new voice and data equipment.

the Police SAPOL, also usea data network SAGRN 19.2 kbit/s RDLAP DATA NETWORKthis is used by their in-vehicle MDT Mobile Data Terminal where can can run checks on people and cars, also have access to whereisit msps, and a whole range of other cool, and interesting features.

External links

* South Australian Government Radio Network [http://www.cto.sa.gov.au/operations/service-delivery/sa-government-radio-network/]
* list of SA-GRN Talk Groups* [http://users.sa.chariot.net.au/~mattb/scan/talkgroups.htm]
*link to more info on the SA-GRN* [http://users.sa.chariot.net.au/~mattb/scan/grn.htm]