What does DMR stand for?
DMR stands for "Digital Mobile Radio" and is a transmission type from the commercial radio sector according to the ETSI standard. Standardization on the air interface enables a wide variety of manufacturers to communicate on one and the same infrastructure or with each other. In analog radio operation, of course, the knowledge of the correct frequencies and, if necessary, a suitable sub-tone (CTCSS) play(ed) a decisive role in order to directly conduct an analog QSO on the local frequencies. This is also possible without any problems as before. In the VFO mode - if available in the unit - frequencies and other parameters can be set as usual, and a call can be made immediately.
Apply for your DMR-ID online
As mentioned above, there are currently 2 major DMR networks, which enjoy worldwide popularity. Both systems coincide due to the technology at some places at others they are again fundamentally different. The DMRplus/IPSC2 network was developed by radio amateurs who were already active in the D-Star mode. Therefore the well-tried and known reflectors were taken over there and one of the two available time slots was assigned to you for it. Thus, time slot 1 is used for national and international operations, while time slot 2 is used for local and regional operations. The philosophy in the Brandmeister network is different. Here, from the beginning, the requirement was to make every TG available on every repeater in every time slot. Initially, reflectors were also used here, but these were switched off after a long announcement on 1.10.2020. Thus the BM network is now a pure talkgroup network.
Software and drivers
Who is already in possession of a DMR device, should install at the latest now the CPS (programming software) as well as the necessary USB drivers on the PC. The current download package usually contains the CPS, the current firmware for the device, the USB drivers as well as text documents describing the installation process and a listing of the firmware changes.
What is the difference between digital and analog radio?
If you have ever listened to digital radio "DMR", the first thing you will quickly be impressed by is the noise-free voice transmission and the information about the calling station shown on the display. In addition to the callsign and DMR-ID, information on the name of the QSO partner and QTH are also available. A prerequisite for participation besides an assigned DMR-ID is the availability of a DMR-capable repeater within range. If there is no repeater in your range, you have the possibility to get the relay "in your own four walls" with the help of a "hotspot". The connection to the Internet is then made via WLan. An Internet connection via the mobile network is also possible and very easy to implement. Basically, it should be noted that many terms originate from the field of professional radio, which may seem somewhat strange at the beginning. However, these terms are quickly "disenchanted" and result in a coherent overall picture. The programming software is also very reminiscent of the software used in professional radios. In the past, professional radios were often operated with a "code plug". This was usually a small memory chip in a housing that was plugged into the radio. The information on this code plug was used to determine which functions were accessible to the radio user, which channels and channel designations were displayed on the radio, which frequencies were assigned to the channels, and much more. Quite similarly it behaves also in the range of the DMR radio. Here, however, the code plug is no longer a physical module that has to be plugged into the device, but it is a file that is quickly and easily written directly to the device via programming software.
The difference to other known operating modes in amateur radio
"What distinguishes DMR from all known networking possibilities in amateur radio is that you work with a talkgroup based system. Furthermore, as in analog operation, simplex connections without repeaters are possible. (DMR-QSO from radio 1 to radio 2). Working via reflectors or rooms is only possible to a limited extent and not in all networks. The system does not provide for a direct connection between relays. Thus, even with handheld radios and low transmitting power, it is possible to make targeted worldwide QSO's, completely free of noise and without the need for antennas with large space requirements. Also to be mentioned at this point would be that one has 2 time slots available in the repeater mode, since here the TDMA procedure is used. Practically spoken, the 2 time slots are like 2 channels, or still more simply 2 relays on a frequency. Thus, it is possible to conduct 2 QSOs simultaneously, but independently of each other on one QRG. As in the other modes, there are several networks. The 2 best known are probably the "Brandmeister" and the IPSC2/DMRplus net. Unfortunately, due to the origin from the commercial radio world DMR cannot work with alphanumeric IDs, what our callsigns are now. Here, a pure numeric ID is needed. Currently (as of 05.2022), there are about 200.000 registered DMR-ID's, and the trend is still rising."
How does it work?
As mentioned above, it is a system with talkgroups. These can be static (always available) or dynamic (only subscribed temporarily). So, the common denominator for a QSO with several participants is usually the talkgroup. Radio amateurs who participate in a talkgroup via a network access point (relay/hotspot) can thus communicate. Furthermore, as in analog mode, simplex connections without repeaters are possible. (DMR QSO from radio 1 to radio 2) Also very interesting: Via a "private call" it is also possible to call a specific radio amateur, worldwide. All that is required is knowledge of the DMR-ID of the person to be called and access to a DMR repeater or HotSpot with Internet connection. Text messages can also be sent to individuals or to a talkgroup. Provided one has an up-to-date contact list in his code plug, the callsign, as well as the name and location of the QSO partner are shown in the display of the own radio.
One mode, but 2 networks
As mentioned above, there are currently 2 major DMR networks, which enjoy worldwide popularity. In some places, the two systems are the same. In others, they are fundamentally different. The DMRplus/IPSC2 network was developed by radio amateurs who were already active in the D-Star mode. Therefore the well-tried and known reflectors were taken over there and one of the two available time slots was assigned to you for it. Thus, time slot 1 is used for national and international operations, while time slot 2 is used for local and regional operations. The philosophy in the Brandmeister network is different. Here, from the beginning, the requirement was to make every TG available on every repeater in every time slot. Initially, reflectors were also used here, but these were switched off after a long announcement on 1.10.2020. Thus the BM network is now a pure talkgroup network.
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There are many codeplugs available for free download on the Internet. However, we strongly advise every beginner not to use these "ready-made codeplugs"! There are also different, also freely available software products and internet sites, which should facilitate the creation of a code plug. However, the handling of these services has to be learned first, which again costs time, makes the start even more difficult and can (and probably will) cause unnecessary frustration. The same applies to the use of exchanged codeplugs, e.g. from the radio club colleague. This actually well-intentioned sharing leads very often to despair, because the operation of the device does not correspond to the actual ideas, a much too large flood of information appears in the display, thousands of repeaters can be called worldwide and the channel names sound "cryptic". It can quickly happen that the desired repeater is not even found in the device. In addition, the device shows unexpected behavior, beeps constantly or simply powers off. Thus, the actual strengths of digital radio, clarity and ease of use, seem to be lost.
When creating the code plug, you will inevitably come into contact with some "technical terms" from the world of digital radio. However, for the time being, we are interested in the following to get you started:
|Time Slot, TS, Slot||Timeslot||TS 1 oder 2|
|Talkgoup, Grp, Group||Speaking group||Virtual condenser room|
|ColorCode, CC||Color code||Value from 1 to 10|
|Receive Group Call List, RX Group List, RX List||Receiving group list||Defines which talk group(s) should be "put through" to the device for reception.|
|Group Call||Group call||Target: Multiple receivers|
|Private Call||Single call||Target: One receiver|
|Zone||Zone||Comparable to a "memory bank|
|Digi Moni||Digital monitor||Allows the "digital squelch" to be turned off and makes all radio operation audible on a repeater|
Connections to the other network
As already mentioned, there are currently 2 large DMR networks, which experience worldwide popularity. And so very quickly the desire was expressed to connect them as well. Unfortunately, these networks are quite different in terms of their logic and philosophy, which in turn, however, gave the development of digital radio in amateur radio a great leap forward. The other side of the coin was an initial arms race and network bashing. But this is now a thing of the past. At the request of many users, it was agreed to partially link the networks. At Hamradio, the OpenBridge protocol was agreed upon, with which some TGs of the various networks are now interconnected. In DL, for example, these are the TGs of the states 2620-2629 as well as TG263. Similar constructs exist in OE and in other countries.
Connections to other modes
Since amateur radio is an experimental radio service, there is of course the possibility to connect to other digital modes. To go into detail here would go beyond the scope. In short, it means that reflectors/rooms of other digital voice modes can be connected with single TGs of the DMR world. As a small tip it should be mentioned that one should not mix the terms of the networks and technologies. So DMR, C4FM, D-Star, NXDN and APCO25 are operating modes. YSF, WiresX, IMRS, XLX,XRF, DExtra, REF, YCS,ircddb, IPSC2/DMRplus and Brandmeister on the other hand are networks and protocols.
How to start?
Basic requirement: First, you need a DMR-capable radio and should be located near a network access point. Since the configuration of a DMR radio can be very complex, you need a software called CPS (Codeplug Programming Software) by most manufacturers. The settings of the radio are then stored in the configuration file (codeplug). Here, in addition to the ID of the radio operator, parameters such as the frequency, the system code, the talkgroups (TGs) and other various settings must be made. A talkgroup can either be accessed directly or a reflector can be connected via control commands, if these are still available in the network.
AT-D878UV2B2 / 3
Full-featured DMR/analogue handheld VHF/UHF transceiver with GPS, Bluetooth, color display and high capacity battery and Bluetooth. With real VFO-mode. The handheld radio is available in 2 variants: with 2100mAh LiIon battery (.B2) or 3100mAh LiIon battery (.B3)
AT-D578-PLUS / PRO
Compact VHF/UHF DMR/analogue mobile transceiver with 2 independant receivers, Bluetooth, GPS, color-display and repeater function. The current version (PLUS) differs only minimally from its predecessor (PRO), so the AT-D578-PRO is also an interesting mobile device for entry-level DMR.