This may be a bit hard to see, but the window shows VFO A in digital mode with a bandwidth of 12.5 kHz. With creating the contacts out of the way, we’ll set up the VFOs next. By limiting ourselves to simplex operations, we’ll only be creating two contacts as shown below. Most DMR repeaters have multiple talk-groups available and each of these would become a group call contact in a normal radio’s codeplug. Everyone tuned in to it can hear the traffic being passed. You can think of a group call as like an analog repeater. We only need to concern ourselves with group calls. We’re also not going to program any repeaters and Internet-connected talk-groups.Ĭontacts in DMR can be group calls, private calls, or all calls. This limits the amount of information stored in the radio to be exploited if the radio is compromised.
With a few exceptions, we’ll be staying away from memory channels. We’re going to concentrate on using the two VFOs available in the DM-1701, with VFO A in the digital mode, and VFO B in analog. You can change that on the fly by using the up or down arrows to select the band, and holding down the red back button until the mode changes. I have my radio set to start up with band A in VFO mode, and band B in Memory Recall. A or B must be set to Freq to access the VFOs. You’ll also need to pay attention to the Freq/Channel Mode.
You can see what that looks like on my radio at right. The ID is set in the General Setting window.
CHIRP DMR PROGRAMMING SOFTWARE
The default ID used by the Customer Programming Software (CPS) that comes with the radio is 1234, and that will work for our purposes. That’s NOT what we want for our team radios. For amateur use, this is an ID associated with your callsign. Normally, each DMR radio is given a unique Radio ID. Thankfully, most of that information isn’t needed for our purposes and we can simplify things considerably. Many, many videos are available on YouTube to guide you through the process of creating a codeplug. When you combine contacts, channels, and zones into a program for a specific radio, you have created what is known in DMRspeak as a codeplug. Broadly speaking you can think of contacts as who you want to talk to, channels as how you want to talk to them, and zones as where you want to talk to them. (As an aside, DMR signals have a very distinctive sound because of the time slots, unlike D-STAR and C4FM, which sound more like white noise.)ĭMR is designed around the concept of contacts, channels, and zones. Finally, because DMR divides each frequency into two time slots in a narrow bandwidth, it also uses your battery more efficiently. In addition, you can create and store messages to use a template, greatly simplifying creation of formatted reports. The DM-1701, according to the manual, lets us create messages of up to 144 characters total over a maximum of 50 lines. The next feature that is particularly useful for us is SMS messaging. In addition to better signal quality over most of its range, digital audio has the advantage that it’s not decodable by an analog only receiver, lending some obscurity to the message being transmitted. In practice this means that you will get better audio longer with DMR, but you’ll be able to understand the analog signal over a greater distance. Analog radio, on the other hand degrades steadily as the distance between stations increases. Like digital television, signal quality is excellent right up to the point where the radio can’t decode it anymore, where it fails quickly. This article is going to give you some ideas for setting them up for your own team.īefore we get into setting up the radio, let’s talk a little bit about Digital Mobile Radio (DMR) and what that standard brings to the table. If you’ve attended NC Scout’s RTO course recently, you know that he’s picked up several of these radios for student use. It includes some features that are not legal on the amateur bands such as two different modes of encryption, but overall, it is a nice radio that’s rugged enough for commercial use.
The DM-1701 is an inexpensive dual-band VHF-UHF DMR/Analog radio.
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