A separate website to provide information on the GBSevenEU NXDN Project in Scotland has been created at: www.nxdnscotland.co.uk The GB7EU NXDN Repeater is now Live and operation with hopefully further NXDN Repeaters in Scotland to follow which will be linked in to NXDN Talkgroup TG23551
The aim of this website is to collate as much information as possible in one place regarding DMR to make it easier for DMR Operators or those interested in getting involved in DMR to find the information.
DMR is for licensed radio amateurs and you must hold a valid amateur radio licence before you apply for a DMR Radio ID number and most definitely before you attempt to press the PTT button. Saying that, there is absolutely no reason why you cannot listen in to DMR.
de Martin MM0DUN
DMR stands for Digital Mobile Radio and uses the Motorola TRBO protocol for communications. Like other digital modes such as D-Star, C4FM and APCO P25, the TRBO protocol converts your voice into a digital form and sends it out via RF (with other bits of information included) and allows you to communicate to other DMR radios and also DMR repeaters, which are networked together around the world via the internet.
What makes DMR stand out from some of the other digital modes is that it utilizes TDMA (Time-Division Multiple Access) to divide a single frequency into 2 distinct “channels” or time slots. By doing this, you can have two conversations going on at the SAME TIME, using one frequency.
Imagine using one frequency while radio A is talking to radio B on time slot 1, and radio C is talking to radio D on time slot 2 … SIMULTANEOUSLY. Pretty neat, huh?
To make matters a little more fun and complicated, each radio must have a unique Radio ID for digital identification between radios and you can also use Talkgroups to separate traffic and target specific groups of DMR users.
A Radio ID is a unique number assigned to you (and your callsign) by the RadioID.net Team. Like a telephone number or IP address, your Radio ID identifies you as a unique radio user on the various DMR networks and repeaters around the world.
With DMR you can:
- Keep in contact with your ham radio contacts using over 800 interconnected repeaters world wide;
- Enjoy static free communications using the latest in digital voice technology;
- Talk longer with extended battery life, allowing up to a 40% improvement in talk time as compared to FM;
- Choose from a wide variety of radio models from a growing list of manufacturers;
- Enjoy automatic roaming capability, allowing operators to keep in contact with one another hands free while on the move
- Easily set-up and link repeaters together using the Internet. No audio levels to tweak or repeaters controllers to manage.
DMR equipment is available from a variety of manufacturers that can easily be used for ham radio purposes. The most commonly used and readily available units are from Motorola and Hytera and there is now an ever increasing number of Chinese made radios which are available at very keen prices and offer dual-band (VHF & UHF) in the same radio.
Below is a video that demonstrates the usage of DMR during the DMR-MARC World Wide Net. Take a listen! (borrowed from the VA3XPR website at www.va3xpr.net)