Friday, October 2, 2015

Listening to Digital Voice communications

I recently have had several inquiries from folks interested in listening to digital voice modes. So this week I came across this interesting article that does a pretty good job of answering some of those questions. The article explains the equipment required to continue listening to many digital Amateur and public service radio transmissions. It covers most of the digital voice modes and the basic functionality of each mode. Though written from the perspective of a Canadian Ham/SWL, it is very applicable to what is happening around the world.

from Scanner Digest #72 (Summer 2015)
CANADA Report - John Leonardelli - VE3IPS

Buzz Buzz Bzzzzrrrp - The Short Guide to Digital Radio

The world of scanning is changing as we move from an
analog world to a digital one. Each digital mode has
different characteristics in how the analog voice is
converted to and decoded from digital. Linking methods
vary across each mode and inter-operability is lacking
between them. Many local amateur radio club nets that
offered interesting listening are now moving to the digital
modes. However, many ARES/RACES groups continue to
offer analog and digital mode nets to test out the
communication readiness.

Every scanner hobbyist needs
to be prepared to listen in on all modes.
Many of these modes require appropriate radios to
monitor them with some SDR methods as well. Please
note that appropriate radio licenses are required to
transmit legally on amateur radio, business and public
band frequencies. In many cases, users will disable
transmit allowing the commercial radio to be used
primarily as a receiver. Many scanner listeners are also
ham radio operators so experimenting in a new digital
mode can be an interesting experience. I am not going to
go into any technical details as those can be easily
gathered on a web search. Let’s explore how a savvy
radio listener can hear these new digital modes and better
understand them.

JARL developed the protocol back in 2004 and has a well established
global amateur radio repeater network already
in place.
D-Star allows 2 linking methods. The Call Sign routing
allows you to communicate with another ham user where
you connect to the local repeater and through an internet
gateway connect with a defined ham user by their call
The other method is via linking into “reflectors” where
users can meet and communicate among each other.
Examples of popular reflectors are the REF001C Mega
repeater, REF005A for the United Kingdom and Listen to
HamNation on Wednesdays nights on REF014C.
Icom is the only manufacture of this equipment. They offer
5 handhelds and mobiles to choose from. The ICR-2500
Scanning receiver does offer an optional Digital Voice
card for reception of this mode. The other method is to
purchase an Icom radio with D-Star for reception. There
are also many boards like the DVDongle that can receive
signals on your computer. You do need to be licensed
amateur radio operator in order to transmit.

Project 25 has been THE North American standard for
LMR Public safety agencies for years. It is part of a
trunked radio system and has two modes of operation.
Phase 1 uses a FDMA standard and the newer Phase 2
offers a 2 slot TDMA standard. This is where a lot of
change has occurred as the older systems have migrated
to Phase 2. Because of this standard change, older
scanners are not equipped to receive the new system due
to the modulation method. The newer scanners such as
the, Uniden BCD436HP, BCD536HP, HomePatrol2, BCD325
P2, BCD996P2 and Whistler WS1080, WS1095 and
PSR-800 (GRE Brand) have the codecs that decode the
proper signals. Along with the migration to Phase 2 many public service
agencies have moved to encryption making reception
impossible. There is some amateur radio activity so check the ARRL
Repeater on-line app for what’s available in your
community. The Toronto GTA has access to a couple of
Ham Radio VHF and UHF P25 repeaters.
The Toronto Public Safety service and York Region has
moved to the new Phased 2 system with encryption.

Digital Mobile Radio is the fastest growing segment of the
digital mode hobby. It is based on Motorola MOTOTRBO
technology. It also offers the largest selection of radios to
choose from. Linking is done via talk groups and they are
managed at the local repeater level. The protocol allows 2
time slots to be available in a single channel. The talk
group concept is an interesting one as you program your
local DMR repeater as a Zone then add your 16 talk
groups. A popular talk group is called North America (Talk
Group 3). There are also various technical nets where a
lot of information is shared and can make for some
interesting listening.
Popular radios are the Motorola 6550 and 7550, Yaesu
Vertex EVX-539, Hytera PD-782 and various new Chinese
entrants. The most popular is the SC700/750 from
Connect Systems.
Toronto has the VA3XPR repeater that is also linked to
the VE3OBI, VE3XPR, and the VE3UHM repeater
provided extended geographical coverage for the golden
horseshoe in the local talk group. This mode has become
the fastest growing digital segment in LMR and Ham
Check listing for LMR service providers using this mode
for their regional networking services.

This is a popular digital mobile radio technology in Europe
with many dPMR446 users on the license free radio band.
This is very popular in the UK. Several Chinese
manufacturers and Motorola make radios. Analogue
PMR446 covers band 446.0–446.1 MHz and digital
dPMR/DMR cover 446.1–446.2 MHz which is in the North
American ham band plan. These radios are illegal for
North American use. However, do not be surprised to find
activity here as many may have purchased these radios
overseas on cruise ships.

Yaesu Fusion
This is also known as C4FM and is another relatively new
digital mode from a Japanese manufacturer. It’s gaining a
lot of popularity as repeater clubs migrate their older
equipment to the newest for a promotional cost of $500.
You do need to be a licensed ham radio operator as your
call sign needs to be entered into the radio. It also
supports the ability to send data and Yaesu has added
microphones with a built in camera allowing photographs
to be sent across the network. What’s interesting about
this mode is that it also supports analog FM transmissions
and like DStar supports GPS functionality. Yaesu now
offers 2 handhelds and 2 mobiles to choose from. Yaesu
using their WIRES modems to allow connectivity between
repeaters. It has not had a lot of success in North America
but that may soon change. Currently, the Fusion mode is
for local communications. It is understood that Yaesu is
looking to increase the level of connected repeaters in the
coming years.
Toronto currently has two repeaters using Fusion and its
VE3TWR and VE3SKY. There should be 8 more club
repeaters coming on-line this summer. Watch activity
increase thereafter.

Kenwood NXDN
This is another variation of a commercial digital mode
called NEXEDGE. The activity is sparse as there are few
amateur radio repeaters but it is growing in the larger
cities. The equipment is purchased through a local
Kenwood LMR dealer. Icom also supports this standard
with their iDAS brand. There are two repeaters in Canada
VE7NYE and VE3SKV. Check Radio Reference for NXDN
networks with LMR users on it.

Terrestrial Trunked Radio is a European trunked radio
standard that has been the backbone of European Public
Safety. It uses a 4 slot TDMA method as its protocol. It is
starting to make headway into North America. The
Toronto Transit Commission has chosen TETRA
technology for its analog system replacement that will be
implemented over the next few years and it’s the system
that will be used by the Toronto PanGames 2015.
It offers a great talk around method, better spectrum
management and improved operations with a direct mode
operation (DMO). DMO allows communications without
repeaters and you can also use a Trunked Mode
Operation (TMO) for use of TETRA repeaters to
communicate. This is done seamlessly.
There is discussion among amateur radio users about
using TETRA for another digital mode to use as
equipment becomes more available.This mode was very
popular in use for the Toronto Panam 2015 Games.

Alinco Digital
Not to be left out, Alinco does offer a digital board for
selected transceivers but its review has not been
favourable and its use has not been widespread. If anyone
has any experience please email e and I can include
some information in the next column.
It does have its own proprietary standards and info is hard
to come by.

How to Receive these Digital Modes?
There are several ways to receive these modes:
1) Amateur radio transceivers. The Icom D-Star,
DMR, and Yaesu Fusion are the easiest methods
2) Commercial radio transceivers. Motorola, Tait,
Sepura, Kenwood, Vertex and Hytera come
quickly to mind as these are typically purchased
from ham friendly land mobile radio dealers. You
do need to buy programming software and for
Motorola it can be $300 for a 3 year term.
3) European FRS radios for dPMR
4) Icom 2500 D-Star and P25 capable receiver
5) Uniden/Bearcat and Whistler/GRE new P25
Phase II scanners
6) AOR Scanners with the add-on ARD300 $900
7) AOR Stand-alone DV1 scanning receiver $1500
8) DSD+ Decoding software running on a PC
connected to a discriminator tap on a scanner or
SDR Dongle
9) Web based receivers that are streaming local
digital audio
The reviews for the new AOR boxes are showing some
great promise to make listening to digital communications
with a simple to use stand-alone receiver as we get
through the initial adoption process and it will get better
and at a lower cost if the SDR receiver manufactures build
their version of a stand-alone receiver.
The challenge that I have with DSD+ is its lack of
portability as many have installed the software on a
netbook and use an older scanner that had the
discriminator tap mod completed. It does not fit easily on
your belt or as an easy mobile in your car but it is doable.

The other challenge with DSD+ is that it can decode all
DMR communications on a repeater across its 2 time slots
but cannot differentiate among different talk groups. This
can make a jumble of conversations confusing when both
time slots on the repeater happen. A scanner listener only
could have a DMR radio programmed with transmit
disabled for the ham radio portion so they can scan and
listen to specific talk groups just like a regular SmartNet
talk group would work.

There is a lot of activity going on right now with digital
modes and the best way to enjoy it is to jump in and start
using the new technologies available to us.

Thanks to John;VE3IPS, for giving us permission to share his article.

...and be sure to check out Scanner Digest at:


  1. Great blog and thanks for posting my article. Back in the 70s my first real hamfest was the Rochester one out in the field. I used to work into Rochester on the 2m sideband net every tuesday night. Great memories

    1. John,
      Thank you for the kind comments. Yes, on the great memeories and thanks for the nice DV article.
      Merry Christmas!
      73- Tony