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Introduction to DMR


DMR, or Digital Mobile Radio, is an Open Standard digital voice and data mode defined by the European Telecommunications Standards Institute (ETSI), and is used in commercial and amateur products around the world.


Designed to operate within the existing 12.5 kHz channel spacing used in licensed land mobile frequency bands globally AND to meet future regulatory requirements for 6.25 kHz channel equivalence, DMR offers:
  • Affordable digital systems with low complexity.
  • Products that are available in all regions of the world.

The DMR protocol covers:
  • Unlicensed (Tier I)
  • Licensed Conventional (Tier II)
  • Licensed Trunked (Tier II)

DMR, similar to P25 Phase II, both use two-slot TDMA (Time Division Multiple Access) in a 12.5 kHz channel, while NXDN uses discreet 6.25 kHz channels using frequency division.

The primary goal of the DMR standard is to specify a digital system with low complexity, low cost, and interoperability across brands, so radio communications end users are not locked into a proprietary solution.

This being said, there are brands which have not adhered to this open standard and have introduced proprietary features that make their products incompatible with some networks.



Open Interfaces, Open Standards, and an Open Philosophy.

In 2005, a Memorandum of Understanding was formed with potential DMR suppliers to establish common standards and interoperability. Although the standard does not specify it, members agreed to use the half-rate DVSI Advanced Multi-Band Excitation (AMBE) vocoder to ensure interoperability.

In 2009, members established the DMR Association to further advance the standard and to maintain interoperability.

Formal testing has been taking place since 2010.



DMR and Ham Radio

  • All-digital network of over 400 repeaters in 37 countries.
  • More than 10,000 registered users
  • Repeaters are connected ALL the time.
  • Excellent voice quality and extended battery life.
  • Less than 1/3 the channel bandwidth of analog FM with twice as many voice channels!
  • Reliable and scalable choice in connectivity



Two-Slot TDMA

DMR Tier II / Tier II occupies a 12.5 kHz bandwidth with tow channels sharing using Time-Division Multiple Access (TDMA). This results in spectrum efficiency of 6.25 kHz per channel.

Bandwidth

Comparing spectrum efficiency of DMR to a wideband FM modulated signal, DMR only uses 25% of the bandwidth per talk channel. Each channel can carry either voice or data, depending on the system design. The two time slots are called Time Slot 1 (TS1) and Time Slot 2 (TS2).

TDMA

For the amateur, this means one repeater allows two separate channels at the same time. Currently, most amateur DMR repeater systems utilize both channels for voice and some limited text messaging. Typically one channel (time slot) is used for wide-area and the second is local and regional talk groups.

 

TDMA Structure



Scalable Connectivity - A Closer Look

Scalable

Scalable programming. Reliable communications.

With DMR, you could choose to operate locally, using simplex, or a repeater using the Local talk group, which is similar to the way we use analog repeaters. From there, however, DMR provides many more options as far as scalability. Choose a Regional talk group for access to repeaters across several states, a National talk group, to access repeaters across the country, or even Worldwide!




Regional Talk Groups

Regional Talk Groups



New England DMR Talk Groups (Available on most DMR-MARC repeaters in New England)

Talk Group Name

Local
Coos Net
Cape Net
Connecticut Statewide
 (SNE)
Maine Statewide
Massachusetts Statewide
New Hampshire Statewide
Rhode Island Statewide
Vermont Statewide

New England Wide
Region North
NETAC 2
Northeast
North America (NA)
World Wide English (WWE)
World Wide Calling (WW)
TAC 310
TAC 311
TAC 317
SKYWARN
NETAC 1
UA 113
UA 123
Parrot
DMR+ USA (Dongle Access)
DMR+ UK
(Dongle Access)
DMR+ Pacific (Dongle Access)
ID

9
8803
8804
3109
3123
3125
3133
3144
3150
3181
8
8802
3172
3
13
1
310
311
317
759
8801
113
123
9998
133
143
153
Description

Local - Single Site Only
Coos County, NH
Cape Cod, MA

Connecticut, Eastern LI, NY QSOs
Maine QSOs
Massachusetts QSOs
New Hampshire QSOs
Rhode Island QSOs
Vermont QSOs
New England Wide + NB
Northern New England
New England TAC 2
New England + NY, NJ & PA
North America (U.S. & Canada)
World Wide English
World Wide (All Languages)
TAC 310
TAC 311
TAC 317
SKYWARN Activations and Nets
New England TAC 1
User Activated English 1
User Activated English 2
Listen to your own audio
DMR+ USA
DMR + UK
DMR + Pacific
Time Slot

TS2
TS2
TS2
TS2

TS2
TS2
TS2
TS2
TS2
TS2

TS2
TS2
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1


Click here for a list of NEDECN Talk Groups



Brandmeister Talk Groups
(Available via Hotspots and some repeaters)


Talk Group Name

Local
Local
Region
World Wide
Europe
North America
Romania
Connecticut Statewide

Maine Statewide
Massachusetts Statewide
New Hampshire Statewide
Rhode Island Statewide
Vermont Statewide

Northeast
TAC 310
TAC 311

WW TAC 1
WW TAC 2
WW TAC 3

English
SOTA
POTA
America Link
Berkshires
ID

1
9
8
91
92
93
226
3109
3123
3125
3133
3144
3150
3172
310
311
901
902
903
913
973
3181
31656
31252
Description

Local - Single Site Only
Local - Single Site Only
Regional
World Wide

Europe
North America
Romania
Connecticut QSOs
Maine QSOs
Massachusetts QSOs
New Hampshire QSOs
Rhode Island QSOs
Vermont QSOs
Northeast QSOs
TAC 310 (Not a Call Channel)
TAC 311
Worldwide TAC 1
Worldwide TAC 2
Worldwide TAC 3
English
Summits on the Air
Parks on the Air
America Link
Berkshires
Time Slot

TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1
TS1

TS1


Click here for a list of Brandmeister Talk Groups
Time slots may vary depending on local repeater preferences



Digital Voice - The Basics

Almost all of us use DV mode virtually every day of our lives. In fact, to many, it is their life! Mobile phones use advanced digital voice modes and the older 2G networks use a version of TDMA very similar to our own. All digital voice standards use encode/decode software called "codecs," which can be proprietary, as in the case of D-STAR, or open source, as in the case of DMR. DMR uses a form of FSK or "frequency shift keying" known as C4FM four level FSK constant envelope modulation. The voice is encoded/modulated, transmitted as a stream of data, then decoded by the receiver. The advantages of DV include easy IP distribution, excellent bandwidth efficiency and high quality audio. DMR applies a channel access protocol known as "Time Division Multiple Access" to allow two timeslots or voice channels within a single 12.5 kHz frequency allocation. Conveniently, the timing alogorithm for this is controlled by the repeater but the latest Motorola radios such as the 4000 series can also provide the facility - Timeslots and Talkgropus - Issue 2 February 2014 - Newsletter of DMR-UK & Yorkshire DMR Group.



First Steps – Registration

Go to the DMR-MARC website and follow the on-screen instructions.

Although it says “User” registration, it is possible to have more than one ID, (but this is not recommended).

A mobile and a base station, for example, could have the same ID as long as they are not transmitting on the same Time Slot and Talk Group at the same time. This is also where you would register a repeater on the DMR network.

Next: Get a Radio!

Manufacturers include: Hytera, Motorola, Kenwood, Vertex Standard, Icom, Connect Systems, Tytera, and more!

CS580   Motorola   CS750

Click here to download a code plug for the Connect Systems CS801 (WS1EC channels)

Click here to download the programming chart for the Connect Systems CS801 (WS1EC channels)

Click here to download a code plug for the Connect Systems CS800D (dual band mobile)

Click here to download the WSSM Intro to DMR presentation



For More Information:


DMR MARC
DMR MARC Worldwide Network
NEDECN
New England Digital Emergency Communications Network




DMR Repeaters (Maine, New Hampshire, and Vermont) 

Call Sign

KQ1L
K1XI
K1YFY
W1LH
K1XI
KB1UAS
N1UGR
W1BHR
N1ME
KC1FRJ
KC1FRJ
W1FCA
W1EMA
KC1FRJ
N1ITR
W1BHR
W1IMD
KC1FRJ
K1DQ
KQ1L
KC1FRJ
N1IPA
KQ1L
K1QVC
K1OX
K1OX
K1LTM
K1LTM
KC1KAM
KB1CFL
W1COS
K1LTM
K1JC
W1IMD
W1WNS
W1MWV
KM3T
W1RCF
K1MOT
K1MOT
NE1B
K1RE
K1RE
WA1ZYX
NN1PA
W1UWS
W1IMD
W1IMD
W1IMD
KI1P
KI1P
KI1P
KI1P
KI1P
KI1P
K1VIT
KA1UAG
KB1VP
WR1VT
Location

Augusta
Boothbay
Buckfield
Calais
Camden
Dexter
Dresden
Farmington
Holden
Ft. Kent
Gouldsboro (Bar Harbor)
Kibby Mt.
Knox
Lincoln
Litchfield
New Sharon
Portland
Presque Isle
Shapleigh
Sidney
Smyrna
Topsham
Waterville
Derry
Chester
Bow
Rochester
Wakefield
Campton
Concord
Clarksville
West Ossipee
Sanbornton
Mt. Washington
Somersworth
Mt. Cranmore (N.  Conway)
Mt. Uncacoonuc
Mt. Uncanoonuc
Hudson
Hudson
Hudson
Gunstock Mt. (Gilford)
Gunstock Mt. (Gilford)
Keene
Goffstown
Mt. Ascutney
Williamstown
Pico Peak
Monkton
Northfield
Burlington
Burke Mtn
Ricker Mt. (Bolton)
Jay Peak
Mt. Snow
Mt. Lincoln (Warren)
Corinth
Mt. Equinox
Brattleboro
State

ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
ME
NH
NH
NH
NH
NH
NH
NH
NH
NH
NH
NH
NH
NH
NH
NH
NH
NH
NH
NH
NH
NH
NH
VT
VT
VT
VT
VT
VT
VT
VT
VT
VT
VT
VT
VT
VT
Frequency

145.170 -
145.200 -
145.320 -
147.045 +
145.370 -
145.220 -
145.430 -
442.400 +
145.310 -
145.200 -
145.210 -
145.120 -
145.420 -
145.350 -
146.700 -
145.140 -
145.340 -
145.180-
145.110 -
145.240 -
147.090 +
145.190 -
146.925 -
145.310 -
145.190 -
145.170 -
145.240 -
145.280 -
145.180 -
145.420 -
145.250 -
147.075 +
145.180 -
448.975 -
145.180 -
448.775 -
444.300 +
145.220 -
145.260 -
447.725 -
147.105 +
145.360 -
447.875 -
444.650 +
145.200 -
448.475 -
448.875 -
444.500 +
443.750 +
TBD
446.475 -
448.575 -
445.075 -
446.375 -
446.275 -
449.475 -
443.900 +
441.350 +
444.400 +
Color Code

12
12
12
1
12
12
12
11
10
12
12
11
12
12
12
11
12
12
4
12
12
13
12
1
9
8
3
7
6
7
0
6
6
2
5
2
10
11
5
1
0
3
9
1
2
5
7
1
7
TBD
1
5
7
7
6
5
8
7
1
Network

NE-TRBO Augusta
NE-TRBO Augusta
NE-TRBO Augusta
NE-TRBO Augusta
NE-TRBO Augusta
NE-TRBO Augusta
NE-TRBO Augusta
NE-TRBO Augusta
NE-TRBO Augusta
NE-TRBO Augusta
NE-TRBO Augusta

NE-TRBO Augusta
NE-TRBO Augusta
NE-TRBO Augusta
NE-TRBO Augusta
NE-TRBO Augusta
NE-TRBO
NE-TRBO Augusta
NE-TRBO
NE-TRBO Augusta
NE-TRBO Augusta
NE-TRBO Augusta
NE-TRBO Augusta
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO/EWARN
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO

NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO
NE-TRBO

Click here for the most current repeater listing, and to find out more about new repeater sites.



NEDECN DMR Nets


Here's a list of some of the nets that take place on various Talk Groups around New England:
  • Sundays at 10 AM is the Maine Dirigo Net on ME Statewide TG (3123)
  • Sundays at 8 – 9 PM is the Providence Radio Association (PRA) Net on NETAC1 TG (8801)
  • Mondays at 7:30 8:00 PM is the New England Digital Swap Net on New England Wide TG (3181).
  • Mondays at 8 – 9 PM is the New England DMR Net on New England Wide TG (3181).  
  • Tuesdays at 8 – 9 PM is the Vermont State DMR Net on VT Statewide TG (3150)
  • Wednesdays at 8 – 9 PM is the YCCC Contesting and DX Net on NETAC1 TG (8801)
  • Thursdays at 8 – 9 PM is the New Hampshire State DMR Net on NH Statewide TG (3133)
  • Thursdays at 7:30 8 PM is the New England SKYWARN DMR Net on the SKYWARN TG (759)
SKYWARN Activations– The National Weather Service in Gray, ME will make call-ups for weather reports on the SKYWARN TG (759).  Please call in with your observations during significant weather events.  In the event of weather activations by multiple weather offices (Gray, Norton, Burlington or Albany) , communications will shift to Statewide Talk Groups as appropriate (ME, NH, MA, RI, VT, etc.).



DMR Simplex Sunday


On Sunday, June 17, 2018, WSSM members set out on a coordinated mountain topping expedition in order to learn more about the range limits of DMR simplex. The longest distance contact achieved was between Mt. Equinox, VT and Saint-Jean-Sur-Richelieu, QC - a distance of: 151.13 mi / 243.22 km (UHF), and the second longest was between Mt. Greylock, MA and Mt. Washington, NH - a distance of: 145.56 mi / 234.25 km (both VHF and UHF).

Click here to read the whole story.




Maine Net Watch (Live Network Activity)



To view other NEDECN Net Watches, click on the links below:

NH/MA/RI Netwatch
VT Netwatch
CT Netwatch
ME Netwatch
NY/NJ Netwatch
CANADA Netwatch

To view the Brandmeister Net Watch, click here





  

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Wireless Society of Southern Maine, P.O. Box 6833, Scarborough, ME 04074