Trends in Digital VoiceParker Radio Association

August 16, 2016W0AKO

Acknowledgements

• WB5PJB Gary – the Elmer’s Elmer!• W9HPX Roland & the Charlotte Digital Radio Group for publishing so

much great information online and sharing with the world• W0RDR Randy – for introducing me to my first Digital Voice radio

several years ago• Digital Voice Experimenters Everywhere, sharing information openly

and freely

AgendaSetting the stage: Since its inception Digital Voice (DV) has come a long way in Amateur Radio, and continues to surge in popularity and usefulness. This presentation highlights some of the current trends and opportunities as it relates to DV.

• Why Digital Voice• How Digital Voice Works• Comparison of the three popular Digital Voice systems• Digital Voice Networks• State of the Art: Digital Voice Hotspots• Art of the Possible: BrandMeister• Summary

Why Digital Voice?• What would you say to nearly noise-free voice quality, clearer transmissions,

and no background interference?• How would you like to allow multiple groups to use one repeater on the same

frequency at the same time?• How would you like to reduce the transmission rate of your radio by one-half

or more, extending the battery life longer than ever before?• How would you like to have your own personal repeater (hotspot) that can

connect to any other repeater across the world?

How Digital Voice Works• A DV transmission is digital data

assembled into packets sent in a continuous stream modulating an RF carrier*

• Each Packet contains a header, sync bits and payload data

• Header provides identity, routing, type of payload, etc.

• The voice payload is data to represent the elements of voice such as frequency, attack, volume, etc.

• Sometimes other data is interleaved (such as text, pictures, or data files)

* Even though DV is a stream of data bits, the FCC regulates it based on its content (i.e. voice)

How Digital Voice Works• An objective of Digital Voice is to reduce signal

bandwidth• A vocoder compresses the digital audio to half

the incoming bit rate – 8 kHz to 4 kHz

• Most all DV systems use the proprietary AMBE family of vocoders made by Digital Voice Systems, Inc.

• AMBE compresses by coding voice characteristics and adds forward error correction for use over a lossy channel

Several competing digital communications systems for Amateur Radio• D-STAR

• DMR

• P-25

• C4FM (Yaesu System Fusion (YSF))

• NXDN

“They are 95% the same and 100% incompatible.” - John Hays K7VE

Three Big Players for Amateurs1. D-STAR (Japan ARL spec published 2001) – HT Entry $350

• Implemented by ICOM & Kenwood solutions (Kenwood announced D-Star HT in 2016), as well as homebrew

• Largest number of amateur users world wide of any DV mode

• Denver area has a linked network of repeaters

2. DMR (ETSI spec published in 2007 in 3 parts) – HT Entry $130• Implemented by Motorola & Hytera, available in several commercial brands, and some amateur brands

(functional interoperability differences between systems)

• Rapidly growing in many areas due to ease of use & low cost of entry

• Rocky Mountain area has robust linked network of repeaters

3. System Fusion (Yaesu spec published 2013) – HT Entry $320• Implemented by Yaesu, only available in Yaesu radios

• Yaesu has indicated their direction is to offer both FDMA and TDMA options

• Repeaters can provide both Fusion and Analog signals

Technical Spec Comparison

D-STAR DMR Fusion

Vocoder AMBE+ AMBE+2 AMBE+2

Forward Error Correction Voice Only Voice Only Voice Only

Modulation GMSK 4FSK C4FM

Multiplex Method FDMA TDMA FDMA

Transmission Rate 4.8 kbps 4.8 kbps x2 9.6 kbps

Bandwidth 6.25 kHz 12.5 kHz 12.5 kHz

Channels supported 1 voice + data 2 voice 1 voice

Standard developer JARL ETSI Yaesu

User Identification

D-STAR DMR Fusion

Registration Required Sometimes Always No

User Identity Call Sign Subscriber ID Call Sign

ID displayed on radio’s display

Call Sign Subscriber ID* Call Sign

Other text displayoptions

4 characters20 characters

No No

Adequate for FCC ID? Yes** No Yes**

* Call Sign displayed if the receiving station’s subscriber ID is programmed in the radio’s contact list; otherwise subscriber ID appears.

** IDing by voice is still a good idea for the benefit of everyone listening.

Repeater Connectivity

D-STAR DMR Fusion

Talk Repeater & Simplex Yes Yes Yes

Link to another repeater User driven Admin driven No

Multi-RepeaterConnection

Reflectors(user driven)

Talk Groups(admin driven)

WIRES-X Rooms(user driven)

Selection method UR entry Channel dial Room name

Route to another ham Yes No No

Echo test Yes Yes No

Request link status Yes No No

Radio Operation

D-STAR DMR Fusion

Memory Selection Dial or GPS Search Key Press Dial

Repeater Connection Selection

Dial Dial Key Press

Mode Selection Method Key Press Fixed in Memory Key Press*

Radio Programming Complexity

Difficult to Easy** Difficult Easy

Newbie Learning Curve Steep Fairly Easy Fairly Easy

* Fusion radios have AMS (automatic mode select)

** Older D-STAR radios are more difficult to program, newer ones are pre-programmed and easy to update

Signal Readability

FM Analog D-STAR DMR Fusion*

Voice Naturalness Good Good Good+ Narrow – Good+Wide – Very Good+

Signal Noise Varies None None None

Sync Robustness N/A Fair Good Good

Sync Recoverability N/A Poor Best Best

* Fusion has two bandwidth voice modes, wide sounds better than narrow.

Sync Robustness is staying in sync vs. the tendency to fall out of sync

Sync Recoverability is the ability to recover sync quickly

The opinions here are highly subjective – yours may differ

Networking Characteristics

D-STAR DMR Fusion

Control Structure User control capability –substantial

Admin controlled –inflexible

Yaesu controlled servers –inflexible

Networking Options Several options (including open source projects) –G2, D-Plus, ircDDB, MMDVM

C-Bridge, Hytera, BrandMeister

WIRES-X

Innovation Ability Many efforts and exciting accomplishments

Limited, but not impossible – growing each year

Limited, but hams are still just getting started

The Digital Voice Network

• Most powerful component of DV is the network• Each mode has its own network(s) and although implemented

differently, each network seeks to achieve the same thing: connect hams together in a seamless virtual experience

• The networks, although separate, have the same key ingredients• D-Star has reflectors• DMR has talkgroups• YSF has rooms

• In all cases, the Internet and IP connected systems form the foundation of the network

• Yes, microwave and other RF links can be used to connect repeaters, but the network is deeper than simply connected repeaters

Understanding Reflectors, TalkGroups, Rooms• D-Star Reflectors

• In simple terms, reflectors allow repeaters & hotspots to link over the Internet• Zero-to-many repeaters can connect to a reflector, and reflectors can interconnect, all

dynamically based on user command (the user controls the network)• Multiple flavors of reflectors, nearly all repeaters can link to any reflector, mostly open system

• DMR Talkgroups• In simple terms, talkgroups are systems of channels shared by one or more repeaters• Activated by users, pre-configured by repeater administrators (admins control the network)• Two main networks, mostly non-interoperable, and many smaller closed networks

• YSF Rooms• In simple terms, rooms are like virtual reflectors/talkgroups accessible via the wires-x network• User created, available to any user on the YSF Wires-X network

State of the Art: DV Hotspots

• Hotspots provide a direct connection to the DV network either onyour computer or via RF on your radio

• Hotspots use the Internet to connect you to the Reflector, Talkgroup, or Room of your choice

• Most hotspots are simplex, and can simulate the repeater experience – it's like having your own personal repeater!

• Hotspots are a fast growing segment of Digital Voice ham radio

Typical Hotspot usage

InternetHotspot

Reflector

Repeater

Repeater

Popular RF based HotspotsUse your radio to talk• DVAP (D-Star): USB dongle with built in transceiver, use PC

or Raspberry Pi with special software ($270)• DV4Mini (D-Star/DMR/YSF/P25): USB dongle with built in

transceiver, use with PC or Raspberry Pi with special software ($130) – cheap but buggy yet very popular on DMR

• DV Mega (D-Star/DMR/YSF): Raspberry Pi hat, use special software (including Android app) very popular ($140 single band, $180 dual band)

• MMDVM (D-Star/DMR/YSF): Arduino DUE shield, interface with most transceivers ($40, $65 w/Arduino)

• SharkRF (D-Star/DMR/YSF): Standalone transceiver + computer ($189, requires Ethernet cable)

Multi-Mode Digital Voice Modem (MMDVM): Let's Eat Cake!

• MMDVMHost is the software engine for the Multi Mode Digital Voice Modem – and you can run it on a Raspberry Pi with DVMega and have a multi-mode hotspot!

• D-Star: full support for all features via ircDDBGateway

• DMR: full support on BrandMeister network (also DMR+ in the UK)• MMDVM automatically switches modes depending on the mode received

• Stays in that mode for 10 seconds (configurable) to allow you to respond in that mode

Art of the Possible: BrandMeister

• BrandMeister is a new DMR focused network that is growing like wildfire • July 1, 2016 - 9:00 AM Worldwide

• 468 Repeaters (506 on 7/28)• 418 Hotspots (456 on 7/28)• 38 Masters

• Although still closed source, it is more open than any other DMR network, allows users to be in control

• Supported by a rich Internet portal

• Starting to be used for interoperability between DV modes• Is accessible via hotspots & homebrew

Summary

• Digital voice is gaining momentum – FAST• DV Hotspots are the future of personal DV ham radio• Lots of options for all modes• Open, user controlled networks are king• Interoperability between modes is possible

• Hotspots are FUN!

Appendix

Hotspot Parts List (one Option)

Part Price

Raspberry Pi B+, 2B, or 3B $35.00

Case for Raspberry Pi $9.00

2m/70cm stubby duck antenna Retevis RT20 $12.00

DV Mega Radio Pi board $129.00

Wifi dongle for Raspberry Pi (if needed) $9.00

2.4A 5v USB Power Adapter $10.00

16GB MicroSD Card (class 10) $8.00

Total $212.00

• Several ways to create a hotspot

• Here is one possible parts list to build from scratch

• Several parts you might already have (SD card, power adapter, antenna)

• Gigaparts bundle $248

DMR Low Cost Entry: TYT MD-380

• Tytera MD-380 – $130 $106

• Includes HT with color screen• Two antennas• Desk charger• Belt clip• Programming cable• Programming software

Demonstration:D-Star / DMR Cross-Linked Reflector

• D-STAR:• Connect to XRF210 D• http://210.xreflector.org/index.ph

p

• Backup: XRF390A

• DMR:• Connect to BM TG31210• http://hose.brandmeister.network

/31210/

• Backup: TG 8500

Portable Digital Voice Repeater Project:N4NZA• Started with this question: What if I could create one repeater

that supports ALL modes: Analog, D-Star, DMR, and Fusion, and package it for field deployable use?

• Based on the Yaesu DR-1X repeater (belongs to the BnanzaRadio Club)

• Configuration 1: NWDigital UDRC (Universal Digital Radio Controller) daughterboard for Raspberry Pi

• Very stable, automatically switches between Analog, D-Star, and Fusion

• Includes full D-Star network support• Configuration 2: MMDVM ZUM daughterboard for Ardurino

with Raspberry Pi controller• Still in development, but working very well• Supports automatic switching between DMR, D-Star, and Fusion• Includes full D-Star network support, DMR BrandMeister network, and

YSFGateway for Fusion• Packaged for field deployment and available for ARESDEC use