Introduction

Terestrial Trunked Radio (TETRA)

Terrestrial Trunked Radio (TETRA) is a four slot TDMA radio technology that fits in a standard 25khz channel. It supports voice, text, and data from up to four talkers (called terminals) simultaneously. It even supports phone calls bridged to the public switched telephone network (think private autopatch). The audio codec is patented, but the code is open source... so experimentation is at least technically possible. Some of the designed applications are public service, emergency response, and railroads. It is very popular in Europe and South America.

Some of it's cooler features include a "gateway" mode, where if one radio can't reach the infrastructure (repeater), but it can communicate with a radio that can, the radio in the middle can act as a bridge. Similarly, the radios can act as virtual repeaters in the total lack of any infrastructure at all: you can talk simplex to any radio you can hear, and through it, any radio it can hear, etc. Imagine being at an event with no repeater coverage, but being able to have a self expanding network of radios on a simplex network.

Here I will explain using DMO mode only, as TMO very expensive.

How to

There are two options, if you are located in an area with repeater/node coverage you only need a TETRA radio. I there is no repeater/node in your area you can setup one an link it to the TETRA Mexico network.

To use an existing repeater you will need:

01 TETRA Radio 430-440 MHz.

Programming periferials (PC, cable, CPS, etc).

Programación del radio

To access the TETRA Mexico radio network you will need to program your radio as follows:

Subscriber Unit Parameters

Radio ISSI = 1234567 (Your ID from www.radioid.net)

DMO Parameters>DMO Group Call Timers

DMO Reservation Time, sec = 1

DMO Parameters>DMO Address Extension

MCC 901
MNC 16383

TalkGroups>DMO>DMO Folders List

DMO Folders List
Name	Status	Transmision Timeout Timer, sec	Transmision Timeout Warning Timer, sec	Number of Talkgroups in Range	Receive Only
DMO Ham	On	120	110	2

En la sección Talk Groups>DMO>DMO Talkgroup List necesitarás programar dos canales con la frecuencia del repetidor/nodo que utilizarás.

DMO Talkgroup List
Name	ID	Status	DMO Folder List	Communication type	Gateway Selection	Gateway Address	Frequency Channel	Receive Call to DMO Partnership Networks	Network MCC	Network MNC	TMO Mapping	Key Group	Incoming Call Minimum Security Class	Outing Call Security Class	Status/Alarm/Addressing	GPS LIP Addressing
Channel 1	1	Programmed	1:DMO Ham	Direct	None		433.650	User Defined	901	16383		NO_KG	Security Class 1	Security Class 1	None	None
Channel 2	1	Programmed	1:DMO Ham	Repeater	None		433.650	User Defined	901	16383		NO_KG	Security Class 1	Security Class 1	None	None

Data Services>Status ID List

Add the following messages to the table. These messages will allow you to connect and disconnect from different Reflectors or Nodes.

SvxLink Mexico Reflectors List

GPS>GPS Settings>GPS

If your radio have a GPS, you can program it. Remember to use LIP, as it it the supported protocol.

GPS>GPS Settings>GPS Location Protocol = LIP
GPS>LIP Configuration/Destination ISSI = 9999

Regresar a Radioafición en Español

Linking to a Reflector

To link a Repeater/Node to a reflector, on your radio press Menu then Messages then Send Status, select the Reflector/Node you want to connect and send a Group Message.

Here is a link to the nodes dashboard.

Dashboard Tetra

Programming a Repetidor/Node

If you want tomset up your own Repeater/Node, you will need the following stuff:

01 Motorola MTM800e or MTM5400 for 430-440 MHz (Gateway).

01 Raspberry Pi 2B or 3B with PSU, etc.

01 FTDI cable for 3.3 Volts RS232 to USB.

01 URIxB interfase or Signalink or R1 2020.

01 UHF antenna with cable, etc.

01 12 Volts PSU

01 Micro SD card with at least 8 Gb.

Internet.

Programming periferials (PC, cable, CPS, etc).

Request a Password for your Node

Entra al siguiente link y solicita una cuenta para solicitar una cuenta nueva para accesar al reflector.

https://forms.office.com/Pages/ResponsePage.aspx?id=WsUri6k2uUyVDFYiLbvQQMlKWpMbYRhDih7oaHFX6dJUMDZPUUJGRUdKRkRKNUI5QkFXRTFTT1hUQi4u

La respuesta te llegará en unas 24 horas.

Download SVXLink

For a Raspberry (Raspbian) version go to:

Download SVXLink for Raspberry Pi

Burn the image on the Micro SD card.

Update Svxlink to the latest version

Login to your Raspberry and run the following commands:

sudo systemctl stop svxlink
cd /home/pi/svxlink/src/build
sudo git pull
sudo make install
sudo systemctl start svxlink

Configure SVXLink

You will need to edit the svxlink.conf file as follows

nano /etc/svxlink/svxlink.conf

Global

If you are using a R1 2020 change te value to 2, if not, leave it as 1.

CARD_CHANNELS=1

ReflectorLogic

HOST=dashboard.vktetra.com

Replace your YourCallSign with your callsign.

CALLSIGN="YourCallSign-L"

Add your ReflectorPasswordHere

AUTH_KEY="ReflectorPasswordHere"

TetraLogic

Replace your YourCallSign with your callsign.

CALLSIGN=YourCallsign

Replace your YourCallSign with your callsign.

APRSPATH=APRS,qAR,YourCallsign-10:

SdsOnUserActivity

Replace your YourCallSign with your callsign.

0=Hello from YourCallSign-L! Refer to vktetra.com for more info.

Tetra_Users

Replace your YourCallSign with your callsign.

0901163830YourRadioISSI=YourCallsign-1,YourName,/1,Tetra DMO Your Gateway Frequency vktetra.com

LocationInfo

Replace 33.12.12S with your Lat using degreens.minutes.seconds

LAT_POSITION=33.12.12S

Replace 151.12.45E with your Long using degrees.minutes.seconds

LON_POSITION=151.12.45E

Replace your YourCallSign with your callsign.

CALLSIGN=EL-YourCallSign

Replace Your Frequency with the one you will be using on your Gateway, i.e. 433.650

FREQUENCY=Your Frequency

Replace Your Suburb with your suburb’s name.

COMMENT=TETRA DMO - Your Suburb Your Gateway Frequency vktetra.com

To save changes press <CTRL> + <X> followed by <Y> and then <Enter>.

Restart to apply all changes.

sudo reboot

Linking you Raspberry to the radio

You will ned to use the rear accessory port.

For the MTM800 the RAP is a 20 pin header.

MTM800
PTT	Pin 3
Tx audio	Pin 5
Analog Ground	Pin 7
Rx audio	Pin 11

For the MTM5400 the RAP is a 26 pin header.

MTM5400
Digital Gnd	Pin 16
PTT	Pin 17
Tx Audio	Pin 11
Analog Ground	Pin 12
Rx Audio	Pin 14
RXD (serial)	Pin 20
TXD (serial)	Pin 25

Programming the Repeater/Node radio

Subscriber Unit Parameters

Radio ISSI = 9999

DMO Parameters>DMO Group Call Timers

DMO Reservation Time, sec = 1

DMO Parameters>DMO Address Extension

MCC 901
MNC 16383

TalkGroups>DMO>DMO Folders List

DMO Folders List
Name	Status	Transmision Timeout Timer, sec	Transmision Timeout Warning Timer, sec	Number of Talkgroups in Range	Receive Only
DMO Ham	On	120	110	1

Talk Groups>DMO>DMO Talkgroup List

Type the frequency you will be using.

DMO Talkgroup List
Name	ID	Status	DMO Folder List	Communication type	Gateway Selection	Gateway Address	Frequency Channel	Receive Call to DMO Partnership Networks	Network MCC	Network MNC	TMO Mapping	Key Group	Incoming Call Minimum Security Class	Outing Call Security Class	Status/Alarm/Addressing	GPS LIP Addressing
Repetidor	1	Programmed	1:DMO Ham	Repeater	None		433.650	User Defined	901	16383		NO_KG	Security Class 1	Security Class 1	None	None

DMO Repeater Mode

This is a work in progress...

If you are going to use your MTM5400 in DMO Repeater mode is used, you must use the wired PTT via raspberry Pi GPIO 16 and modify the Tx section accordingly, it is not possible to use the PEI interface to key the transmitter on when a broadcast from the network needs to be transmitted by the MTM5x00.

Wired PTT via GPIO16 and modify the Tx section accordingly.

TBD

Install Phyton Serial

sudo apt-get install python-serial

sudo nano /home/pi/serial_write-CR.py

#!/usr/bin/env python
import serial
ser = serial.Serial(port='/dev/ttyUSB0',
  baudrate=9600,
  parity=serial.PARITY_NONE,
  stopbits=serial.STOPBITS_ONE,
  bytesize=serial.EIGHTBITS,
  timeout=1
)

ser.write(13)
ser.close

sudo chmod +x /home/pi/serial_write-CR.py

Test with

./serial_write-CR.py

You will need to edit the rc.local file:

sudo nano /etc/rc.local

Add the following lines to the file:

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.
# Print the IP address
_IP=$(hostname -I) || true
if [ "$_IP" ]; then
printf "My IP address is %s\n" "$_IP"
fi

# GPIO 16 = PTT
echo "16" >/sys/class/gpio/export
sleep 2
echo out >/sys/class/gpio/gpio16/direction

# GPIO 19 = SQL
echo "19" >/sys/class/gpio/export
sleep 2
echo "in" >/sys/class/gpio/gpio19/direction

# GPIO 18 = Utility
echo "18" >/sys/class/gpio/export
sleep 2
echo out >/sys/class/gpio/gpio18/direction

# GPIO 23 = Stop button directly handling in python script.
# Clears the MTM buffer by sending a CR

/home/pi/serial_write-CR.py
(…)
exit 0

Press <CTRL> + <X> then <Y> and last <Enter>.

sudo nano /usr/share/svxlink/events.d/TetraLogic.tcl

# Executed each time the squelch is opened or closed #
proc squelch_open {rx_id is_open} {
Logic::squelch_open $rx_id $is_open;
puts "Le squelch change: $is_open";
  if {$is_open==0} { exec echo 0 >sudo /sys/class/gpio/gpio18/value; }
  if {$is_open==1} { exec echo 1 >sudo /sys/class/gpio/gpio18/value; }
}

Audio leveling

On the command line type:

sudo alsamixer

Choose your external sound card (the one you qre using to talk to the radio). Adjust the input and output levels. For that, you can use the Parrot Reflector 9990.

Finally, save your audio change with the following command:

sudo alsactl store 0

Connecting to Echolink (optional)

Run the following commands, watch the upper case and lowercase “L” on Echolink word.

sudo mv /usr/lib/arm-linux-gnueabihf/svxlink/ModuleEchoLink.so   /usr/lib/arm-linux-gnueabihf/svxlink/ModuleModuleEcholink.so 
sudo cp /etc/svxlink/svxlink.d/ModuleEchoLink.conf   /etc/svxlink/svxlink.d/ModuleEcholink.conf

Edit the following file with your Echolink information.

sudo nano /etc/svxlink/svxlink.d/ModuleEcholink.conf

Notice that the first line need to be modified as follows (watch the “l” on Echolink.

[ModuleEcholink]

Edit the following lines with your Echolink account information.

if 0 then Echolink transmits to the gateway otherwise no!

MUTE_LOGIC_LINKING=0

CALLSIGN=MYCALL
PASSWORD=Password
SYSOPNAME=Tu Nombre
LOCATION=[Svx] Frecuencia, Ciudad

DESCRIPTION="You have connected to a SvxLink node,\n"
            "a voice services system for Linux with EchoLink\n"
            "support.\n"
            "Check out http://svxlink.sf.net/ for more info\n"
            "\n"
            "QTH:     My_QTH\n"
            "QRG:     Simplex link on 433.650 MHz\n"
            "CTCSS:   901-16383\n"
            "Trx:     TETRA DMO\n"
            "Antenna: Comet/Omni/GP-3\n"

Press <CTRL> + <X> then <Y> and last <Enter>.

Restart to apply changes.

sudo reboot

SvxLink Beginners Guide

Contents

Introduction

How to

Programación del radio

Subscriber Unit Parameters

DMO Parameters>DMO Group Call Timers

DMO Parameters>DMO Address Extension

TalkGroups>DMO>DMO Folders List

Data Services>Status ID List

GPS>GPS Settings>GPS

Linking to a Reflector

Programming a Repetidor/Node

Request a Password for your Node

Download SVXLink

Update Svxlink to the latest version

Configure SVXLink

Global

ReflectorLogic

TetraLogic

SdsOnUserActivity

Tetra_Users

LocationInfo

Linking you Raspberry to the radio

Programming the Repeater/Node radio

Subscriber Unit Parameters

DMO Parameters>DMO Group Call Timers

DMO Parameters>DMO Address Extension

TalkGroups>DMO>DMO Folders List

Talk Groups>DMO>DMO Talkgroup List

DMO Repeater Mode

Audio leveling

Connecting to Echolink (optional)

Navigation menu

SvxLink Beginners Guide

Introduction

How to

Programación del radio

Subscriber Unit Parameters

DMO Parameters>DMO Group Call Timers

DMO Parameters>DMO Address Extension

TalkGroups>DMO>DMO Folders List

Data Services>Status ID List

GPS>GPS Settings>GPS

Linking to a Reflector

Programming a Repetidor/Node

Request a Password for your Node

Download SVXLink

Update Svxlink to the latest version

Configure SVXLink

Global

ReflectorLogic

TetraLogic

SdsOnUserActivity

Tetra_Users

LocationInfo

Linking you Raspberry to the radio

Programming the Repeater/Node radio

Subscriber Unit Parameters

DMO Parameters>DMO Group Call Timers

DMO Parameters>DMO Address Extension

TalkGroups>DMO>DMO Folders List

Talk Groups>DMO>DMO Talkgroup List

DMO Repeater Mode

Audio leveling

Connecting to Echolink (optional)

Navigation menu

Search