Radio : PMR (Personal/Professional Mobile Radio)

Narrowband (typically 12.5 KHz of UHF) communication systems for voice and data.

Examples

  1. TP9500
    The TP9500 supports multiple modes. Analog Conventional, MPT Trunking, DMR Tier 2 Conventional, and DMR Tier 3 Trunking

    Available:
    VHF: 136-174MHz,
    UHF: 378-470MHz (H5), 450-520MHz (H7), 762-870MHz
Output:
    3W
Channels/Zones:
    1,500 channels / 26 zones and 16 channels

  2. DMR-6x2 | Kit @ RadioMadeEasy.com
    BTECH DMR-6X2 DMR & Analog Dual Band Two-Way Radio-7W VHF/UHF (136-174MHz & 400-480MHz), Encryption, GPS, Talker Alias, Voice Recording, with Large Accessory Kit

PMR446

Private Mobile Radio, 446MHz is a licence-exempt UHF-band service available for business and personal use in most countries throughout the EU. The European equivalent to US/Canada's FRS.

FRS (Family Radio Service)

A personal radio service in USA intended for families and individuals. FRS is the USA equivalent of EU's PMR446.

FRS radios use narrow-band FM.

22 Channels

12.5 kHz channel spacing (used in land mobile frequency bands globally)

0.5W per channel.

2.0W @ Channels 1-7, 15-22.

FRS/GMRS hybrids exist due to their overlapping frequency bands.

GMRS (General Mobile Radio Service)

A personal radio service intended for families and individuals. It's popular for short-range, personal, or recreational communication and does not require specialized knowledge or equipment. GMRS radios can be used without a business license, but they do require an FCC license in the U.S.

License required; 1 per family.

UHF frequencies in the 462-467 MHz range with analog FM modulation.

Land-mobile FM UHF radio service designed for short-range two-way voice communication

Trunked Radio Systems

Digital radio is required.

A trunked radio system is a packet-switching network, forming a two-way radio, that uses a control channel to automatically assign frequency channels to groups of user radios. In a traditional half-duplex land mobile radio system a group of users (talkgroup) with mobile and portable two-way radios communicate over a single shared radio channel, with one user at a time talking.

MPT-1327 | RadioReference.com

Legacy analog trunked radio communication networks standard create in 1988 by UK's Ministry of Posts and Telegraph (MPT).

Primarily used in the UK, Europe, SA, Australia, New Zealand and China. Many countries had their own version of number/user interface, including MPT1343 in the UK, Chekker (Regionet 43) in Germany, 3RP (CNET2424) in France, Multiax in Australia, and Gong An in China.

MPT systems are still being built in many areas of the world, due to their cost-effectiveness.

P25 AKA Project 25 AKA APCO-25

Developed by public safety professionals in North America. Fragmented/Bureucratic per metropolis. Now has broader application worldwide, though mostly USA. P25 is digital replacement for analog UHF (typically FM) radios, adding the ability to transfer data as well as voice for more natural implementations of encryption and text messaging. P25 radios are commonly implemented by dispatch organizations, such as police, fire, ambulance and ERS (Emergency Rescue Service), using vehicle-mounted radios combined with repeaters and handheld walkie-talkie use.

The two protocols are not compatible, but Phase 2 radios are backwards compatible with phase 1 modulation and analog FM modulation, per the standard. P25 Phase 2 infrastructure can provide a "dynamic transcoder" feature that translates between Phase 1 and Phase 2 as needed.

EU has created TETRA (Terrestrial Trunked Radio) and DMR (Digital Mobile Radio) protocol standards, which fill a similar role to P25.

P25 open interfaces

P25's Suite of Standards specify eight open interfaces between the various components of a land mobile radio system. These interfaces are:

Same/Similar systems :

DMR (Digital Mobile Radio)

Overview

A digital radio standard requiring an FCC license on specific frequencies. Designed for professional, commercial, and public safety applications. It’s used by organizations that need reliable, high-quality communications over a wider area and with advanced capabilities like dispatch, location tracking, and emergency calling. It's often integrated into professional networks or used by licensed amateur radio operators on amateur bands.

Conventional (Direct) and Trunked modes.

DMR is a digital replacement for analogue PMR (Private Mobile Radio).

An ETSI standard.

30 MHz - 1 GHz

12.5 kHz channel spacing (used in land mobile frequency bands globally)

Two voice channels through two-slot TDMA technology.

The PMR/DMR markets can be roughly divided into three broad categories:

Tiers

DMR interface

ETSI standards:

Channels / Licensing

DMR operates in shared VHF (136-174 MHz) and UHF (403-527 MHz) bands, but specific channel access is controlled through licensing. In most countries, government agencies (like the FCC in the U.S.) allocate portions of these bands for public safety, government, commercial, and private business use.

DMR is used on the amateur radio VHF and UHF bands. Coordinated DMR Identification Numbers are assigned and managed by RadioID Inc. Their coordinated database can be uploaded to DMR radios in order to display the name, call sign, and location of other operators.

Repeaters / Hotspots

Internet-linked systems such as DV Scotland Phoenix Network, BrandMeister network, TGIF, FreeDMR and several others allow users to communicate with other users around the world via connected repeaters, or (RPi) DMR "hotspots".

There are currently more than 5,500 repeaters and 16,000 "hotspots" linked to the BrandMeister system worldwide. The low-cost and increasing availability of internet-linked systems has led to a rise in DMR use on the amateur radio bands. Some Raspberry Pi-based DMR hotspots, often those running the Pi-Star software, allow users to connect to multiple internet-linked DMR networks at the same time. DMR hotspots are often based on the FOSS Multimode Digital Voice Modem (MMDVM), hardware with firmware.

TETRA (Terrestrial Trunked Radio formerly Trans-European Trunked Radio)

An ETSI standard deployed in sixty countries, and the preferred choice in Europe, China, and other countries.

TETRA uses a four-slot TDMA in a 25 kHz channel of a trunked radio system

TETRA terminals can act as mobile phones (cell phones), with a full-duplex direct connection to other TETRA Users or the PSTN.

NXDN (Next Generation Digital Narrowband)

Conventional and Trunked modes. Conventional is called Direct Mode Operation (DMO).

In DMO, TETRA radios operate more like traditional two-way radios in a peer-to-peer or simplex setup. It’s commonly used by first responders and organizations needing direct communication when infrastructure is unavailable.

Marine VHF Radio

Emergency radio for ships; a worldwide system of two way radio transceivers on ships and watercraft used for bidirectional voice communication from ship-to-ship, ship-to-shore (for example with harbormasters), and in certain circumstances ship-to-aircraft.

It uses FM channels in VHF band (156 and 174 MHz), designated by the ITU as the VHF maritime mobile band. In some countries additional channels are used, such as L and F channels for leisure and fishing vessels in the Nordic countries (at 155.5–155.825 MHz). Transmitter power is limited to 25 watts, giving them a range of about 100 kilometres (62 mi; 54 nmi).

Marine VHF radio equipment is installed on all large ships and most seagoing small craft. It is also used, with slightly different regulation, on rivers and lakes. It is used for a wide variety of purposes, including marine navigation and traffic control, summoning rescue services and communicating with harbours, locks, bridges and marinas.

 

Amateur (Ham) Radio AKA Amateur Radio Service

Q code

A collection of 3-letter codes developed as operating signals for Morse Code. Q code messages can stand for either a statement or a question. Example query/answer:

Q: 'QSL?'

Means "Do you confirm receipt of my transmission?"

A: 'QSL'

Means "I confirm receipt of your transmission."

First twelve Q-codes

Listed in the 1912 International Radiotelegraph Convention:

Code       Question                             Answer or notice

QRA        What ship or coast station is that?  This is ____.
QRB        What is your distance?               My distance is ____.
QRC        What is your true bearing?           My true bearing is ____ degrees.
QRD        Where are you bound for?             I am bound for ____.
QRF        Where are you bound from?            I am bound from ____.
QRG        What line do you belong to?          I belong to the ____ Line.
QRH        What is your wavelength in meters?   My wavelength is ____ meters.
QRJ        How many words have you to send?     I have ____ words to send.
QRK        How do you receive me?               I am receiving (1–5). (5) is perfect.
QRL        Are you busy?                        I am busy.
QRM        Are you being interfered with?       I am being interfered with.
QRN        Are the atmospherics strong?         Atmospherics (noise) are very strong.

Listing according to service

QAA to QNZ – Assigned by the International Civil Aviation Organization (ICAO).
QNA to QNZ – ARRL developed its own QN Signals for message handling. 
                (They overlap with other signals.)
QOA to QQZ – For the Maritime Mobile Service.
QRA to QUZ – Assigned by ITU Radiocommunication Sector (ITU-R).

All services (QRA–QUZ)

Code       Question                         Answer or notice
...
QRZ        Who is calling me?               You are being called by ____ (on ____ kHz (or MHz)). 
...
QSL        Can you acknowledge receipt?     I am acknowledging receipt. 
...

QSL Card

A written confirmation of either a two-way radiocommunication between two amateur radio or citizens band stations; a one-way reception of a signal from an AM radio, FM radio, television or shortwave broadcasting station; or the reception of a two-way radiocommunication by a third party listener. See Q-code list above for details of the QSL reference.

A typical QSL card is the same size and material as a typical postcard, and most are sent through the mail as such.

FCC Examinations for Radio License Levels