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The the amateur radio service, the majority of DMR repeaters are connected to others by way of some sort of centralized network controller. Many independent and experimental systems are connected to the Brandmeister network, while other repeaters may be linked through other regional and national networks like K4USD, Interstate, SCHEART, NCPRN, and TGIF.
DMRVA is Virginia's statewide DMR linked system. Through a partnership with HEARS, the combined DMRVA-HEARS network of over two dozen repeaters provide rapid, reliable communications across the state through the use of two linked C-Bridge controllers.
This page highlights some of the special features of DMR and their implementation on the DMRVA network, focusing primarily on the Richmond Metro repeater cluster.
DMR Terminology Refresher
DMR Terminology Refresher
Timeslot (TS)
A division of the 12.5 kHz DMR channel into two alternating “time slices.”
Allows two separate voice or data paths to share the same frequency at once (TDMA).
Radios and repeaters coordinate so that one call happens in Timeslot 1 while another happens in Timeslot 2, effectively doubling capacity.
Talkgroup (TG)
A virtual “channel” or addressing scheme that determines who hears a transmission.
Each transmission is tagged with a talkgroup ID, and only radios programmed to listen to that TG (on that timeslot/frequency) will unmute.
Lets many user groups share the same repeater or network without interfering with each other.
Talkgroup Matrix
A document published by many DMR network operators that lists the available talkgroups on each timeslot and any special system configuration parameters or usage guidelines.
Codeplug
A file that contains all of the contacts, channels, zones, radio settings, and other data necessary to make a DMR transceiver operational.
DMRVA+HEARS Combined System Map
DMRVA+HEARS Combined System Map
Orange = Richmond Metro cluster repeaters
Yellow = Richmond Metro portable repeaters - home locations
Blue = DMRVA and HEARS-VA networked repeaters
One benefit of DMR is the ability to have two simultaneous voice or data conversations through a repeater on a single 12.5 kHz channel.
Local and Metro Talkgroups
Local and Metro Talkgroups
On most DMR networks, the Local talkgroup (usually 9 or 27500) does not leave the local repeater.
Many of the DMRVA network repeaters are arranged into clusters that share a Local talkgroup. We call these arrangements Metros. For example, the Richmond Metro cluster consists of the Richmond, Beaverdam, Goochland, Middlesex, New Kent, Petersburg, Powhatan, and RVA portable repeaters. All of those are linked via the Local talkgroup. A few repeaters do have a traditional, freestanding Local talkgroup. This table shows the current Local/Metro arrangements as of July 2025.
RVA Metro
RVA Metro
The RVA Metro talkgroup can be a little confusing. Its talkgroup number varies depending on how and where you're accessing the network.
► When you are on a repeater in the RVA Metro repeater cluster* use talkgroup 27500.
► From the Spotsylvania repeater, from a Brandmeister repeater, or from a hotspot use talkgroup 31511.
Using the incorrect talkgroup number might seem to kinda-sorta work under the right circumstances, but for reliable communication be sure to set your radio to the talkgroup numbers shown here.
* The RVA Metro repeater cluster includes Beaverdam (BEA), Goochland (GCH), Lexington #1 (LX1), Middlesex (MDX), New Kent (NKC), Petersburg (PBG), Powhatan (POW), Richmond (RIC), and the Richmond portable repeaters (POR).
Programming Your Radio
Programming Your Radio
The DMRVA network is well supported by the RATS Codeplug Project, which furnishes high-quality codeplugs for dozens of popular DMR transceivers. You can use one of our files or build your own by following the DMRVA talkgroup matrix. A few things to note when setting up your radio for use on any DMRVA network repeater:
► Your radio must transmit a valid radio ID issued by RadioID.net.
► The only open-access talkgroups that are available are those listed on the official DMRVA talkgroup matrix.
🛑 The use of All Call is restricted on some repeaters including the RATS system. We recommend omitting this from your programming if possible.
🛑 Turn off GPS (APRS) position beacons. These are not supported on the DMRVA network and they may cause unpredictable behavior for other users.
Richmond area hams! Beware of commercial radio dealers and other unscrupulous individuals offering expensive codeplug creation and radio programming services! RATS can help you get your DMR transceiver up and running on the DMRVA network, and it won't cost you a penny! RATS codeplugs are:
► Updated in sync with DMRVA expansions and talkgroup matrix changes. Nobody has fresher codeplugs for central Virginia!
► Built to a high standard with consistent zone and channel setups, and multi-point quality assurance checks.
► Community-reviewed for accuracy. User feedback is always welcome.
► 100% FREE. RATS will never charge you for troubleshooting and programming assistance, even if you're not a member.
And even if you don't own an officially "supported" radio, the RATS Codeplug Project and Elmer Team are available to answer your questions about DMR programming. We can help you remotely with troubleshooting your codeplug, download/USB driver issues, and other common problems. How can we help?
Static vs. Dynamic Talkgroups
Static vs. Dynamic Talkgroups
Some DMRVA talkgroups are configured as static or always-on talkgroups, and others are dynamic or PTT-controlled.
Static or Always-On Talkgroups
Static or Always-On Talkgroups
These talkgroups are always active on every DMRVA network repeater:
Local or Metro
VA Statewide
HEARS
Echo Test (Parrot)
When using these talkgroups:
► No special steps are required to make or receive a call.
► Do not kerchunk first. It is not necessary to activate these talkgroups.
► Do not use the Clear Timeslot function. It has no effect on these talkgroups.
Dynamic or PTT-Controlled Talkgroups
Dynamic or PTT-Controlled Talkgroups
These must be activated by a user and time out after several minutes of inactivity:
TAC A, B, and C
Regional talkgroups - Peninsula, Tidewater, Southwest, Shenandoah Valley
WV Statewide (select repeaters only)
When using these talkgroups:
► Kerchunk the talkgroup -- briefly press your PTT button, just long enough to get a talk permit tone/message. This will command the repeater to establish the link.
► Wait. Audio begins at the start of the next transmission. You won't hear any transmissions already in progress.
► Kerchunk the Clear Timeslot talkgroup to drop the connection.
The DMRVA talkgroup matrix lists static talkgroups as "On" and dynamic talkgroups as a number, either 5 or 15, which represents the idle timeout on that channel. Distant talkgroup activity is not enough to keep a dynamic talkgroup active. You will need to reactivate a talkgroup if there is no traffic from your end of the link before the timeout.
Special Features
Special Features
DMR offers many unique features like direct radio-to-radio calls, text messaging, and data connectivity. There is also a special talkgroup set aside for public service events on some DMRVA repeaters. Most of these features do not propagate across the network so they're only available between users of the same repeater, with limited exceptions.
Beaverdam (BEA) is the only non-Motorola repeater on the DMRVA network. Data features may behave unpredictably or may not function at all depending on the application and configuration.
Private (Direct or Radio-to-Radio Calls)
Private (Direct or Radio-to-Radio Calls)
Radio-to-radio calls are permitted on the DMRVA network. To establish a call, all you need is the other station's radio ID.
► "Private" calls are not actually private -- anyone with a radio set to promiscuous mode can receive your transmission.
► Except for calls between Richmond and Petersburg, private calls do not leave the repeater. You cannot make a private call to someone on another repeater or network.
► Private calls do not cross timeslots -- you cannot make a private call to someone on timeslot 1 from timeslot 2, or the other way around.
► Private calls and other radio-to-radio features such as radio checks may perform unpredictably if either station has more than one radio in operation under the same ID.
All radio-to-radio calls are to take place on timeslot 1. To achieve this, have your radio set to any timeslot 1 talkgroup when placing your private call.
Text Messaging
Text Messaging
DMR allows the exchange of short text messages between any two or more radios with unique radio IDs. Text messages can be directed to an individual radio or to an entire talkgroup, provided the sending and receiving radios are all speaking a commonly understood language. There are at least three common text messaging protocols:
DMR Standard SMS - Defined in the ETSI DMR standard. Supported by newer Motorola and many non-Motorola transceivers. No delivery acknowledgment or retry.
Motorola Text Message Service - Motorola proprietary format. Supported by all Motorola and many non-Motorola radios. Shorter message length, with acknowledgement.
Hytera Messaging - Hytera proprietary format. Supported by Hytera and a small number of non-Motorola radios.
Usually, the SMS mode setting in the radio determines the protocol used for new outbound messages, and the radio will often receive any other supported protocols, replying with whichever protocol was received. That is, the radio may be set to send Motorola messages, but it may still receive DMR SMS and reply to inbound SMS as SMS.
Things to know about text messaging:
► Text messages are not private. Anyone with a radio in promiscuous mode may receive your group and radio-to-radio messages.
► Radios in promiscuous mode may display garbage or behave erratically when receiving messages with an unsupported protocol.
► Except for messaging between Richmond and Petersburg, text messages do not leave the repeater. You cannot message someone on another repeater or network.
► Text messages do not cross timeslots -- you cannot message someone on timeslot 1 from timeslot 2, or vice-versa.
► For Motorola TMS and Hytera messaging, both the sender and recipient must have unique radio IDs. Messaging may perform unpredictably if more than one radio is using the same ID.
We recommend the use of timeslot 1 for all messaging. To do this, have your radio set to any timeslot 1 talkgroup when sending your message.
Unlike mobile phone text messaging, DMR messaging is not a store-and-forward system. It involves direct radio-to-radio communication (or radio-to-repeater-to-radio) with no intermediary messaging server. If the recipient's radio is not on and tuned to the same repeater and timeslot, they will not receive your message.
🛑 Text messages are not permitted to any talkgroup that appears on the DMRVA talkgroup matrix. If you need a messaging talkgroup assigned for a special application, please contact techcomm@rats.net and we'll get you in touch with the right people.
DMR IP Data
DMR IP Data
DMR provides for the transmission of very small amounts of data between stations. It is best suited for UDP-based applications where reliable transmission is not essential. The IP data interface can also be used to send and receive text messages. DMR IP data services require a Motorola or Hytera branded transceiver, USB cable, radio drivers or compatible network stack, and a unique ID for each radio.
► IP addresses are calculated from radio IDs. Each data radio on the same repeater must have a unique ID.
► Except for between Richmond and Petersburg, DMR IP data connections do not leave the repeater or timeslot.
► Data applications should be on timeslot 1, except timeslot 2 may be used during special events with prior authorization.
► You are required to use a software or hardware firewall to prevent unwanted (non-DMR) packets from going out over the DMR network interface.
► Repeater trustee authorization is required prior to using data applications on the DMRVA network. Data applications may not be welcome on all repeaters.
We have two pages of DMR IP Data related information. See our IP Data & Messaging page, and our information on Data Station Identification.
Special Event TAC C
Special Event TAC C
There are two public TAC channels on the DMRVA network -- TAC A and TAC B. Anyone can use these two channels.
In 2024, a third TAC channel was established on select repeaters, utilizing timeslot 2.
► TAC C is available on the Richmond (RIC), Petersburg (PBG), and Portable repeaters (POR) only.
► This is a closed-access talkgroup intended for emergency overflow use at public service events.
All use of TAC C requires prior authorization.
Where to Get Help
Where to Get Help
For additional information, check out our DMR FAQ.
► To find a codeplug for your radio, for CPS download links, and other programming related resources, visit the RATS Codeplug Project.
► For codeplug programming assistance, contact the RATS Codeplug Project via email.
► For general DMR operating procedures, technical questions, equipment problems, or other assistance, the RATS Elmer Team is available.
► To report a problem with the RATS repeater system, contact our Technical Committee.
► You can also ask your question in the #digital-voice channel of the RVAHams Slack service.
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