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Digital Amateur Radio

The following are the different digital modes being used the the Durham Region area. Some of the repeaters are in multi-mode, where different modes are available in addition to regular FM voice.

DMR – Digital Mobile Radio

DMR, or Digital Mobile Radio, is explained in more detail, via my scanner DMR page, but a more simplistic explanation follows:

Tier I

DMR Tier I products are for license-free use in the 446 MHz band in the European Union.

This part of the standard provides for consumer applications and low-power commercial applications, using a maximum of 0.5 watt RF power. With a limited number of channels and no use of repeaters, no use of telephone interconnects, fixed/integrated antennas, and a talk timer of 180 seconds, Tier I DMR devices are best suited for personal use, recreation, small retail and other settings that do not require wide area coverage or advanced features.

Tier II

DMR Tier II covers licensed conventional radio systems, mobiles and hand portables operating in PMR frequency bands from 66-960MHz. The ETSI DMR Tier II standard is targeted at those users who need spectral efficiency, advanced voice features and integrated IP data services in licensed bands for high-power communications. ETSI DMR Tier II specifies two slot TDMA in 12.5 kHz channels.

DMR Tier II is based on the following ETSI standards.

  • ETSI TS 102 361-1 Air interface
  • ETSI TS 102 361-2 Voice and generic services and facilities
  • ETSI TS 102 361-3 Data protocol

Tier III

DMR Tier III covers trunking operation in frequency bands 66-960MHz. The Tier III standard specifies two slot TDMA in 12.5kHz channels. Tier III supports voice and short messaging handling similar to MPT 1327 with built-in 128 character status messaging and short messaging with up to 288 bits of data in a variety of formats. It also supports packet data service in a variety of formats, including support for IPv4 and IPv6.

Talk Groups

Talk Groups (TG) are a way for groups of users to share a time slot, without distracting and disrupting other users of the time slot. It should be noted that only one Talk Group can be using a time slot at a time. If your radio is not programmed to listen to a Talk Group, you will not hear that Talk Group’s traffic.

The DMR-MARC Mototrbo™ network supports a number of Talk Groups on TS1 including World Wide (TG1, PTT), North America (TG3), and World Wide English (TG13). TS2 is for local, state, and regional Talk Groups. The DCI/TRBO network uses TG3163 for North America and TG3161 for World Wide, and TG3 for World Wide English on TS2.

The DMR standard also supports private calls (one-to-one), encryption, and data. Private calls are not allowed by most of the amateur networks and many consider private calls not amateur friendly; private calls tie up a large number of repeater time slots across the network. Encryption is not legal on amateur radio in the USA but is allowed in Canada! Data and text messaging is supported on some networks.

For simplex traffic, the accepted standard in the amateur community is to use TG99 on TS1 with CC1.

DMR Repeaters

The following DMR repeaters are available in the Durham Region area:

BrandMeister Network

VE3OBI – Courtice – 442.1375 – CC1
VE3SBX – Ajax – 442.3625 – CC3
VE3LBN – Oshawa – 443.9875 – CC3
VA3WIK – Toronto – 442.1875 – CC4
VE3NUS – Toronto – 444.2875 – CC1

TalkGroups
9 = Local/Region
91 = Worldwide
93 = North America
99 = Simplex
302 = Canada
310 = TAC-310
311 = TAC-311
3023 = Ontario

DMR-MARC Network

VA3XPR – Toronto – 442.3375 – CC1 (Disabled due to jamming)

The following are the different digital modes being used the the Durham Region area. Some of the repeaters are in multi-mode, where different modes are available in addition to regular FM voice.

DMR – Digital Mobile Radio

DMR, or Digital Mobile Radio, is explained in more detail, via my scanner DMR page, but a more simplistic explanation follows:

Tier I

DMR Tier I products are for license-free use in the 446 MHz band in the European Union.

This part of the standard provides for consumer applications and low-power commercial applications, using a maximum of 0.5 watt RF power. With a limited number of channels and no use of repeaters, no use of telephone interconnects, fixed/integrated antennas, and a talk timer of 180 seconds, Tier I DMR devices are best suited for personal use, recreation, small retail and other settings that do not require wide area coverage or advanced features.

Tier II

DMR Tier II covers licensed conventional radio systems, mobiles and hand portables operating in PMR frequency bands from 66-960MHz. The ETSI DMR Tier II standard is targeted at those users who need spectral efficiency, advanced voice features and integrated IP data services in licensed bands for high-power communications. ETSI DMR Tier II specifies two slot TDMA in 12.5 kHz channels.

DMR Tier II is based on the following ETSI standards.

  • ETSI TS 102 361-1 Air interface
  • ETSI TS 102 361-2 Voice and generic services and facilities
  • ETSI TS 102 361-3 Data protocol

Tier III

DMR Tier III covers trunking operation in frequency bands 66-960MHz. The Tier III standard specifies two slot TDMA in 12.5kHz channels. Tier III supports voice and short messaging handling similar to MPT 1327 with built-in 128 character status messaging and short messaging with up to 288 bits of data in a variety of formats. It also supports packet data service in a variety of formats, including support for IPv4 and IPv6.

Talk Groups

Talk Groups (TG) are a way for groups of users to share a time slot, without distracting and disrupting other users of the time slot. It should be noted that only one Talk Group can be using a time slot at a time. If your radio is not programmed to listen to a Talk Group, you will not hear that Talk Group’s traffic.

The DMR-MARC Mototrbo™ network supports a number of Talk Groups on TS1 including World Wide (TG1, PTT), North America (TG3), and World Wide English (TG13). TS2 is for local, state, and regional Talk Groups. The DCI/TRBO network uses TG3163 for North America and TG3161 for World Wide, and TG3 for World Wide English on TS2.

The DMR standard also supports private calls (one-to-one), encryption, and data. Private calls are not allowed by most of the amateur networks and many consider private calls not amateur friendly; private calls tie up a large number of repeater time slots across the network. Encryption is not legal on amateur radio in the USA but is allowed in Canada! Data and text messaging is supported on some networks.

For simplex traffic, the accepted standard in the amateur community is to use TG99 on TS1 with CC1.

DMR Repeaters

The following DMR repeaters are available in the Durham Region area:

BrandMeister Network

VE3OBI – Courtice – 442.1375 – CC1
VE3SBX – Ajax – 442.3625 – CC3
VE3LBN – Oshawa – 443.9875 – CC3
VA3WIK – Toronto – 442.1875 – CC4
VE3NUS – Toronto – 444.2875 – CC1

TalkGroups
9 = Local/Region
91 = Worldwide
93 = North America
99 = Simplex
302 = Canada
310 = TAC-310
311 = TAC-311
3023 = Ontario

DMR-MARC Network

VA3XPR – Toronto – 442.3375 – CC1 (Disabled due to jamming)

TalkGroups
1 = World Wide
2 = Local 1
3 = North America
8 = Golden Horseshoe Area
9 = Local 2
13 = WW English
113 = UAE 1
123 = UAE 2
302 = Canada
310 = TAC310
3023 = Ontario
3022 = Quebec
3024 = Manitoba
3026 = Alberta
3029 = New Brunswick
3027 = British Columbia
9998 = Parrot
9999 = Audio Test

Presently, all Toronto area DMR-MARC repeaters have been disabled due to jamming/interference.

NXDN – Next Generation Digital Narrowband

The NXDN (Next Generation Digital Narrowband) common air interface protocol, which was developed jointly by ICOM and Kenwood, uses Frequency Division Multiple Access (FDMA), employing a 4-level FSK modulation scheme. These companies and others together form the NXDN Forum.

Kenwood’s brand for NXDN equipment is “NEXEDGE”, while Icom’s brand for NXDN equipment is “IDAS”, or Icom Digital Advanced System. For a more detailed information via my scanner NXDN page.

NXDN Repeaters

The following NXDN repeaters are available in the Durham Region area:

TalkGroups
1 = World Wide
2 = Local 1
3 = North America
8 = Golden Horseshoe Area
9 = Local 2
13 = WW English
113 = UAE 1
123 = UAE 2
302 = Canada
310 = TAC310
3023 = Ontario
3022 = Quebec
3024 = Manitoba
3026 = Alberta
3029 = New Brunswick
3027 = British Columbia
9998 = Parrot
9999 = Audio Test

Presently, all Toronto area DMR-MARC repeaters have been disabled due to jamming/interference.

NXDN – Next Generation Digital Narrowband

The NXDN (Next Generation Digital Narrowband) common air interface protocol, which was developed jointly by ICOM and Kenwood, uses Frequency Division Multiple Access (FDMA), employing a 4-level FSK modulation scheme. These companies and others together form the NXDN Forum.

Kenwood’s brand for NXDN equipment is “NEXEDGE”, while Icom’s brand for NXDN equipment is “IDAS”, or Icom Digital Advanced System. For a more detailed information via my scanner NXDN page.

NXDN Repeaters

The following NXDN repeaters are available in the Durham Region area:

Work in progress..

Written by
VA3DBJ

Canadian amateur radio operator since 2007. Operating on the VHF/UHF bands and local repeaters in the Durham Region area. Husband and the father of four.

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Home Digital Amateur Radio

Digital Amateur Radio

The following are the different digital modes being used the the Durham Region area. Some of the repeaters are in multi-mode, where different modes are available in addition to regular FM voice.

DMR – Digital Mobile Radio

DMR, or Digital Mobile Radio, is explained in more detail, via the Amateur Radio DMR page.

NXDN – Next Generation Digital Narrowband

NXDN is an open standard Common Air Interface (CAI) technical protocol for mobile communications. It was developed jointly by Icom Incorporated and Kenwood Corporation.NXDN is implemented by Icom in their IDAS system and by Kenwood as NEXEDGE; both Kenwood and Icom now offer dual-standard equipment which supports the European dPMR standard.

Icom and Kenwood began their collaboration in 2003. The NXDN protocol was announced in 2005, and NXDN-compatible products first appeared in 2006.

The NXDN Common Air Interface (CAI) was accepted at the Study Group 5 (SG5) meeting of the International Telecommunication Union Radiocommunications Sector (ITU-R) held in November 2016 and in report M.2014-3 published in February 2017 as an international digital land mobile system.

Technical Information

NXDN uses Frequency-Division, Multiple-Access (FDMA) technology in which different communication streams are separated by frequency and run concurrently. Time-Division, Multiple-Access (TDMA) systems combine the communications streams into a single stream in which information from the different streams is transmitted in interleaved time allocations or “slots.” Code-Division, Multiple-Access (CDMA) systems allow many users to share a common spectrum allocation by using spread-spectrum techniques.

The basic NXDN channel is digital and can be either 12.5 kHz or 6.25 kHz wide. 6.25 kHz dual-channel systems can be configured to fit within a 12.5 kHz channel. This effectively doubles the spectrum efficiency compared to an analog FM system occupying a 12.5 kHz channel. The architecture of NXDN is such that two NXDN channels, within a 12.5 kHz channel for example, can be allocated as voice/voice, voice/data, or data/data. As of 2012, this capability cannot be implemented in commercially available hardware on simplex or “talkaround” frequencies, but only through repeaters.

Systems that use NXDN also support mixed analog FM and digital NXDN equipment, including direct radio-to-radio communications. This allows system owners to migrate to a narrowband, digital system without replacing the entire system at once. NXDN equipment is currently FCC type-accepted for use on VHF (137-174 MHz) and UHF (406-512 MHz) bands.

Data is transmitted using 4-level frequency-shift keying (FSK) modulation. NXDN uses the AMBE+2 vocoder (codec) for digital audio. This combination provides better weak-signal voice quality than for analog FM. For an equivalent transmitter power, NXDN is represented as having a wider range and slightly better multi-path characteristics than analog FM in typical RF environments, specifically at the 12 dB SINAD threshold. The transmission bit rate is 4,800 bit/s.

The following FCC emission designators apply to NXDN transmissions:

  • 8K30F1E 12.5 kHz single channel digital voice
  • 8K30F1D 12.5 kHz single channel digital data
  • 8K30F1W 12.5 kHz single channel digital voice and data
  • 4K00F1E 6.25 kHz single channel digital voice
  • 4K00F1D 6.25 kHz single channel digital data
  • 4K00F1W 6.25 kHz single channel digital voice and data
  • 4K00F2D 6.25 kHz single channel analog CW ID

Audio Quality

In all lossy compression schemes, trade-offs are made in voice reproduction quality in return for minimizing the raw bit rate of the transmission. This leads to artifacts and compromises of frequency response in reproduced speech. Encoders and other compression schemes that are highly optimized for speech are often unsuitable for non-speech audio, such as music or frequency-shift keyed data. Using an inappropriate encoder usually results in the creation of distortion and artifacts in the reproduced audio.

The audio reproduction quality of IDAS and NEXEDGE communications systems is dependent on the performance of the AMBE+2 voice codec used by NXDN. The AMBE family of vocoders has been subjected to comparative testing and found to be adequate for its intended uses, primarily mobile and aeronautical radio. The AMBE+2 vocoder has also been selected for use in the Motorola MOTOTRBO radio family as well as Hytera’s DMR systems, and the Project 25 (P25) mobile radio system. The following reports and papers are descriptions of laboratory-environment evaluations of AMBE+2 and other speech vocoders.

Compromises in audio quality are inherent in the use of any codebook-based speech coder, particularly when used in conditions of high background noise. Incremental improvements are being made in the algorithms, which may lead to differences in performance even while the basic method remains unchanged. In the US, the Department of Commerce Public Safety Communications Research laboratory regularly reports on progress in this field. While their work specifically pertains to Project 25 radios, it is directly applicable to any system using similar multi-band excitation coders.

NXDN Repeaters

The following NXDN repeaters are available in the Durham Region area:

Still under construction.

Written by
VA3DBJ

Canadian amateur radio operator since 2007. Operating on the VHF/UHF bands and local repeaters in the Durham Region area. Husband and the father of four.

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