MULTIMODE DIGITAL VOICE COMMUNICATION
WITH DMR FOCUS
JANUARY 19, 2018
TOBIE BOUTOT
WHO AM I
• VE9XAB – Tobie Boutot
• Started as Power Electronic Engineer at UNB
• Designed and Built high power converter for renewable energy conversion
• Research Engineer – Dissociation of methane into its element using plasma
• High Power Microwave - plasma in chemical process
• Integration of an autopilot in fixed-wing drone
• Research Engineer at U de Moncton
WHY DIGITAL???????
• Bandwidth
• FCC is moving other services to narrow band
• DV modes use no more than 12.5 KHz, some 6.25
• Clear Quiet Audio
• Digital audio does not include hiss or noise, even as signals weaken.
• Digital just drops out entirely when signal too weak
• Digital Extras
• Radio can display Callsigns, Text Messages, more
POPULAR DIGITAL MODES IN AMATEUR RADIO
• D-Star – Digital Smart Technologies for Amateur Radio (FDMA)
• Wires-X/System Fusion - Wide-coverage Internet Repeater Enhancement System
(FDMA)
• NXDN (IDAS/NEXEDGE) – Icom/Kenwood Collaboration (FDMA)
• DMR – Digital Mobile Radio (TDMA 2-TS)
• P25 (Phase 1) – Project 25 or APCO P25 (Phase 1 FDMA, Phase 2 TDMA 2-TS)
• TETRA - Terrestrial Trunked Radio, formerly known as Trans-European Trunked Radio
(TDMA 4-TS) No known U.S./Canada amateur deployments
HOW POPULAR ARE THEY
• DMR- 1165 repeaters >10000 registered users
• D-Star- 1143 repeaters
• Wire-X/Fusion- 314 repeaters
• P25 248 repeaters
• NXDN- 93 repeaters
DIGITAL VS ANALOG
DMR AND DIGITAL VOICE (DV)
• FDMA (Frequency Division Multiple Access)
• D-Star
• P25 Phase 1
• NXDN
• TDMA (Time Division Multiple Access)
• DMR Tier 2
• P25 Phase 2
• DMR Tier 3 – Trunk system, 2-slot TDMA, multi-channels
DMR – DIGITAL MOBILE RADIO
DMR is divided into three “Tiers”
• Tier I (single channel)
• Tier II (2-slot TDMA– the standard for Amateur Radio)
• Tier III (trunking protocol)
DMR – HALF THE CHANNEL BANDWIDTH
Traditional Analog
25 kHz
Channel Bandwidth
1 Channel
1 Repeater
DMR
12.5 kHz
Channel Bandwidth
2 Channels
1 Repeater
fc fcfc + 12.5 fc - 12.5 fc – 6.25 fc + 6.25
2 CHANNELS – ONE FREQUENCY
Each TDMA Channel is 60ms long, containing 2 x 30ms time slots
DMR TERMINOLOGY
• Talk Groups - Think of a Talk Group as a repeater or as a group of repeaters that are activated when you
key them up.
• Channels - A Channel is a specific Talk Group on a specific repeater.
• Zones - A Zone is a grouping of individual channels
• Color Codes - DMR repeaters use Color Codes (CC) much like analog repeaters use CTCSS or DCS
• Code Plugs - A code plug is simply a radio’s configuration file
• TS – Time Slots – DMR has 2 time slot – 2 independent DV channel
• Roaming
• C-bridge - The C-Bridge in essence is part database manager, part master control hub; and part gateway. It
is responsible for the assignment of what talk groups are available to a particular network; as well as the
repeaters attached to that network. Think of it almost like a router for DMR talkgroups.
• Admit Criteria - The Admit Criteria determines when your radio is allowed to transmit
SOME DMR PORTABLE RADIOS
SOME DMR MOBILE RADIOS
I HAVE A DMR RADIO – WHAT’S NEXT
• You NEED to get an ID before you transmit
• https://www.radioid.net/#!
• Lots of info on:
• http://www.dmr-marc.net/
DMR-MARC REPEATER MAP - WORLDWIDE
DMR REPEATER - FREDERICTON
Callsign: VE9FTN
Frequency: 147.165
Offset: + 0.6 KHz
Color Code: 1
DMR REPEATER – SAINT-JOHN
Callsign: VE9SJN
Frequency: 145.490
Offset: - 0.6 KHz
Color Code: 1
DMR REPEATER – GRAND FALLS
Callsign: VE9ARZ
Frequency: 145.290
Offset: -0.6 KHz
Color Code: 12
DMR REPEATER – SPRINGHILL, NS
Callsign: VE1XPR
Frequency: 145.290
Offset: -0.6 KHz
Color Code: 1
DMR REPEATER – MONCTON
• Callsign: VE9DMR
• Frequency: 146.925
• Offset: +0.6 KHz
• Color Code: 1
TALK GROUPS ON OUR SYSTEM
SO… WHAT IS MULTIMODE DIGITAL VOICE?????
• Hardware & Software that support more than
• one DV mode
• So one repeater can support DMR QSOs,
• D-Star QSOs, Fusion QSOs, P25 etc.
• One mode at a time – other mode radios will
• not hear, but will see a busy repeater
• Or a Homebrew Hotspot can do the same
WHY MULTIMODE?
• With limited coordinations on VHF and even UHF, one repeater can support
several modes
• MultiMode Hotspots at home or travelling give us more flexibility, now and in
the future
• Two kinds of MultiMode users:
• Those preferring a single mode, using proven H/W & S/W, with flexibility to try a new
mode
• Those who like several modes, have several radios, and use all of them
• Some users even have several Hotspots, one for each mode
POPULAR MULTIMODE PRODUCT
• MMDVM – Jim KI6ZUM just gave you details. Open Source and Creative Commons.
Various board versions available; most popular are the ZUM board and ZUMspot.
Sold by Bruce Given VE2GZI: mmdvm.blogspot.com
• DVMEGA Dutch hotspot RF boards, works with G4KLX software, so similar
experience to MMDVM products
• BlueDV Software supports AMBE3000 devices like the Northwest Digital Radio’s
ThumbDV
• DV4mini German designers, created DSP modem DVRPTR. USB stick is low power
hotspot that supports multiple modes
• SharkRF openSPOT Stand-alone device, separate computer like Pi not needed. Local
transcoding DMR-Fusion.
QUESTIONS ?