DMR stands for Digital Mobile Radio and is one of the digital modes available for ham radio. The other digital modes are D-Star, Fusion and P25. This website will concentrate on DMR and how it’s used with ham radio.
DMR radios generally talk to a repeater just like analog radios. They can also communicate in simplex mode when a repeater isn’t available and the receiving person is within range of the radio. DMR radios can also communicate without a repeater using local “hot spots.” Hot spots are like mini repeaters (i.e., low power) that are connected to the Internet to connect to users world wide. No matter how you connect to the DMR network, it still involves a DMR radio talking through a DMR repeater; talking to a hot spot; or talking directly to another DMR radio using simplex.
There are a number of radios available for DMR from Motorola, Hytera, TYT (Tytera), Connect Systems, and Tera. There are other DMR radios but I feel these are the popular ones at the time of this writing (February 2017). Currently the price of DMR radios range from $100 to $800 USD.
DMR radios are generally UHF (70cm) or VHF (2 meters). At this time there are no dual-band DMR radios because of the lack of commercial demand for dual-band (which may change if ham radio manufacturers get into the market). In our area (Northern California) there are more UHF DMR repeaters so you need to check which repeaters are popular in your area before deciding which type of radio to buy.
Advantages of DMR over Analog
The following are the advantages of DMR:
* Noise free communication. With DMR you are either in the repeater or your out which means crystal clear communications
* Talk to the world. Because DMR repeaters and hot spots are generally connected to the internet, communications across town; across the state; across the nation; and across the world is possible. Because of the nature of the digital communication, talking with someone around the world sounds like just talking to someone across town.
* It’s been stated that DMR is more efficient than analog which means you can communicate further with the same power as analog.
* DMR occupies a 12.5KHz bandwidth that can share two channels. This means that one repeater can carry two conversations using two time slots (TS1 and TS2).
Disadvantages of DMR
As will all good things, there are always some negative.
* DMR requires a DMR-capable radio
* It also requires a DMR repeater in your area. (You can purchase a Hot Spot if you don’t have a repeater nearby.)
* New terminology. Someone new to DMR must learn the lingo, which may be confusing at times.
* As of this writing there are no Ham-only DMR radios. Since all the current DMR radios are made to be use in commercial services (police, fire, etc.) they don’t support front-panel programming. This means you need Computer Programming Software (CPS) and a computer in order to program the radio or change any configurations or button assignments.
* Radios are programed using Code Plugs, which seem to confuse many users. To confuse matters more, Code Plugs require you to know about Zones, Color Codes and Talk Groups.
In upcoming articles we will address the terminology and code plugs and how DMR radios are programmed.