DMR

Oklahoma DMR

This is the home for Digital Mobile Radio (DMR) information in Oklahoma. DMR radios use repeaters from Motorola Solutions branded MOTOTRBO (a.k.a. TRBO) DMR Radio. MOTOTRBO has some additional features added to a standard DMR radio including something called IP Site Connect. This is what’s used to network these repeaters in the USA, and all over the world. When one person transmits, multiple repeaters can be keyed up on the network (like a reflector) without the user having to fumble through finding node numbers or access codes. The Oklahoma repeaters switched from the DMR-MARC network to the Brandmeister network on November 16-18, 2016.

Each repeater is either a UHF, or VHF full duplex transmitter/receiver pair that connects to a duplexer, and then finally to an antenna in some vertically advantageous location. Here in Oklahoma, all of our repeaters are in the UHF band. Typically, these are on towers, mountain tops, or tall buildings. Here in Oklahoma, the mountaintop option doesn’t come into play much. Each repeater has a frequency pair by the Oklahoma Repeater Society, Inc. The repeater owner enters his or her callsign into the repeater so that it can provide the required CW identification. A color code identifies the repeater. The magic happens when a Master Server IP address is entered into the server, and the repeater connects via the Internet to a Master Server.

Each handheld or mobile radio needs to be programmed to get it to work. Just like any other recent ham radio you use a computer to set the controls. What is obvious is that you need to program the frequencies of each repeater. The next piece of information is a ‘color code’, which is a number from 0 to 15. Think of that as a CTCSS tone. The two final pieces are time slice and talk group. Each of these variables are described below. In the radio business, we call this collection of information, a ‘code plug’. In common words, this information would be called a configuration file. We’ve collected codeplugs, and the links to the software to download these configurations to your radio on our codeplugs page.

Oklahoma Repeater Summary

Currently, there are 24 DMR operating repeaters located in Oklahoma using the Brandmeister Network. The Granite repeater is using the DMR-MARC networking system.

							
DMR ID	City	       Frequency	Color	Offset	Trustee
314000	Calumet		444.3250	1	+5 MHz	AE5DN
314001	Hogshooter	442.1875	1	+5 MHz	W5RAB
314002	Tulsa South	442.1625	2	+5 MHz	WD5ETD
314003	NW OKC		442.6250	1	+5 MHz	AE5DN
314004	Fort Gibson	442.1250	1	+5 MHz	WA5VMS
314005	Tulsa Central	442.4750	2	+5 MHz	W5RAB
314006	Keetonville	442.3500	1	+5 MHz	W5RAB
314007	Stillwater	444.4750	1	+5 MHz	AE5DN
314008	Mannford	444.4500	1	+5 Mhz	W5RAB
314009	Granite		442.0750	1	+5 Mhz	K5XTL
314010	Mounds		444.8500	1	+5 MHz	W5RAB
314011	Ponca City	444.7500	1	+5 Mhz	K5BOX
314012	OKC Downtown	443.2250	1	+5 MHz	W5GDL
314013	Bartlesville	444.4750	2	+5 MHz	W5RAB
314014	Big Cabin	443.8250	1	+5 MHz	W5RAB
314015	Depew		444.3750	1	+5 MHz	W5RAB
314016	Norman		443.8250	1	+5 MHz	N5MS
314017	Lawton		443.6000	4	+5 MHz	N5PLV
314018	OKC East	443.1750	1	+5 MHz	KB5KWV
314019	SE Edmond	443.0500	1	+5 MHz	W5RLW
314020	Edmond		442.3250	1	+5 MHz	W5RLW
314021	Leonard		443.6500	1	+5 MHz	W5RAB
314024  North OKC       442.5000        1       +5 MHz  N5KNU
314026  Cleora          442.6250        1       +5 MHz  W5BIV

Timeslices

The DMR system splits the radio signal into two distinct channels, called timeslices. These are named Timeslice 1, and Timeslice 2. Effectively, this allows two different audio channels to be sent and received simultaneously, from the same repeater. To program the radio correctly, you need to know which talk group is on which timeslice for your desired repeater. In Oklahoma, we’ve agreed that Timeslice 1 should be for International, National, or Regional traffic. We use Timeslice 2 for Statewide and more local talk groups. Technically this is done by splitting the signal into 30 millisecond long pulses. Data compression allows the data to be sent quicker than 1/2 the ‘real time’ of the audio information.

Talk Groups

Talk groups (TG) are used to separate repeater traffic by the ‘size’ of the area you will use. The Oklahoma repeater administrators have set up all of our repeaters up in a similar way for the static talkgroups. One of the good points of the Brandmeister system is that the user can select what talk groups they want to hear. As such, the static groups are just the ones transmit all day. You can use any other talkgroup as long as you kerchunk that talkgroup once every 15 minutes. This static short list of Oklahoma repeaters are as follows:

Time Slot #1 - Group Call 31095 = US Call Sign Region 5
Time Slot #1 - Group Call 31400 = Oklahoma TAC (for ARES type events)

Time Slot #2 - Group Call 3140 = OK Statewide
Time Slot #2 - Group Call 31401 = OK Central (For Depew and West)
Time Slot #2 - Group Call 31402 = OK East (For Depew and East)
Time Slot #2 - Group Call 3140xx = Local repeater group

More Brandmeister talkgroups are listed on the Brandmeister wiki.

A selected few Brandmeister talkgroups are detailed as follows:

  • Local TG 2 – Stays on the same repeater, and isn’t routed to any other repeater. This talkgroup stays local to each repeater, so it is not available to hear on the Brandmeister Hose.
  • Norman OK TG 314016 – This talkgroup should be used by all that want to connect back to Norman area hams from remote locations. Think of this as a ‘SCARS/Norman Talkgroup’. The codeplugs supplied from this site will have this talkgroup in the receive list, so the locals can hear our people that are connecting from remote ‘dongle’ based systems, or are connecting from the rest of the globe, and want to talk back to us. This is set up as a static group on the Norman Repeater in Time Slice 2. Click here to listen to this talkgroup online, on the Brandmeister Hose, in real time.
  • Parrot Private Call TG 9990 – This talkgroup will record what you transmit, and then play it back to you after you unkey your transmitter.

Receive Lists

Each channel is a receive list that defines which talkgroups, on the same time slice, you will listen will hear. If you are programming a channel for Central OK, you must add a receive list that has the Central OK talkgroup in it. You can add other talkgroups to this list, and if they are transmitting on this channel’s timeslice, you will be able to hear them, as well. Typically, it’s good practice to have a channel available that has a receive list for only the channel you’re talking on, so you hear the other party, and another that has a receive list with all of the talkgroups available, so you can listen to what is on the other talkgroups.

Weekly Oklahoma ARES Monday Night Net

Every Monday night there’s an ARES net on the statewide DMR (3140) talk group at 8:15 pm Central Time. The purpose of this net is to communicate statewide ARES information and to test the use of the statewide talk group for emergency purposes. Typically you’ll hear check-ins from across the state, and now with Brandmeister, across the globe, on this net. Take a listen, and check in to join the fun.

More DMR Nets

We’ve collected a bunch more DMR nets, and have listed them on the W5NOR meetings page.

Brandmeister User Guide

Here’s a great User Guide for the systems connected to the Brandmeister DMR networking system.

Online Repeater Map

Brandmeister maintains an online repeater map, here, to help you locate repeaters inside, and outside of Oklahoma.

Brandmeister

The Brandmeister Network website is the best source of DMR information. The Brandmeister Wiki website is a great place to start looking for Brandmeister DMR information.

Getting Started – Codeplugs

The best way to get started on DMR is to use a configuration from a person who’s in your area. Don’t forget that you’ll need to add your callsign, and DMR number to the codeplug before you download it to your computer. Once you get it running, you should then look at that codeplug, and see how you need modify it for your use. We’ve collected codeplugs, and the links to the software to download these configurations to your radio on our codeplugs page.

Color Codes

Each repeater is assigned a “color code” that acts similar to a CTCSS tone in the analog world. A user must properly program their radio with the frequency of the repeater, the offset (typically similar to the analog equivalents), and the color code of that repeater. This color code allows two repeaters to share a frequency, at great distances, and not interfere with each other on “good propagation” days. There’s no significance to these codes. They need to match between the repeater and the client radio.

DMR ID Numbers

Each repeater and amateur radio operator needs to obtain a DMR ID number. Each operator only needs one number. Program this number into each radio. This number is a 32 bit number, in the form of a seven digit decimal number. The DMR Id ties your callsign to the radio transmissions so the real-time displays, both in the radios and on the web, will know who’s transmitting. The use of this number does not constitute an official legal ID.

DMR Real-time monitoring

One of the benefits of connecting all of these radios is that the administrators can create real-time displays. This real-time display will show every transmission, from every radio, from across the world. Take a look, and you’ll see who’s talking, and on what repeater. This helps to see if your signal is getting out or to see if your transmission is getting any packet loss between you and your nearest repeater.

APRS GPS information

A number of the ham DMR radios have an option to transmit their GPS locations via the Amateur Radio Packet System (APRS) network. Information from a properly set up radio will appear on the APRS.FI web system. The people that run the PAPA network have a great document titled Brandmeister Getting Started Guide, and on page 8 of that document, they have a great GPS setup guide. Currently, the Motorola radios have been demonstrated to make this work. The Hytera systems may have some troubles, and the TYT MD 390’s are still not making connections. Brandmeister has setup Talk Group 310999 as the site for you to point your GPS information toward…

DMR Etiquette

Operation on the DMR protocol is very similar to what you’ve become used to on a VHF/UHF FM repeater, with a few minor differences.

  • Use the repeater that gives you the best signal. Usually, that’s the one that’s closest to you, but you should experiment with those near you to make sure you sound good to others. Remember to use the Parrot channel on each repeater to see what your audio sounds like.
  • Check your audio level. Since the audio is digitized on your radio, and there’s no leveling happening in transit, it’s very important for you to send a proper audio level. Use the Parrot, or ask your friends to verify that your audio level is proper, and remember the mic to mouth distance for your radio.
  • Use the smallest area talk group to make the communication work. If you and the person you’re talking to are using the same repeater, be sure to use the Local talkgroup. If you’re both in the Central OK area, then use that talkgroup. Both in OK, use the Oklahoma Statewide channel. OK/TX area, use Regional, etc.
  • The USA talkgroup is ONLY to be used as a calling frequency. Make your call on this channel, and then arrange to change to a TAC talkgroup, like 310, 311, and 312. Make sure that these talkgroups are clear before you start having your conversation on one of the TAC’s. Asking “Is this talkgroup in use?” is a good way to start that message. If so, try the next TAC Channel.
  • When you wish to talk with anyone on a given talkgroup, it is common to give your callsign, your location, and the talkgroup. For example, “This is N5HZR, in Norman on Central Oklahoma”.
  • Remember that there are two different timeslots on each repeater (1 & 2). You may see your radio indicating a receive light, and hear nothing. This traffic may be the CWID, or on the other timeslot, or a talk group that you’re not listening to.
  • When you press the Push-To-Talk (PTT) button, wait to hear the confirmation tones before you start talking. When you push the button, your radio contacts the repeater and makes sure it’s not busy, and that you can hit the repeater. A long tone, or no tone when you hit the PTT means your transmission did not go through.
  • If you’re in a conversation with another person, and for some reason, you lose contact with them, it may be that either end has traffic that blocks your conversation. Watching your receive light will let you know if the blocking is happening at your end. Simply wait for a clear condition, and try again.
  • Each channel has a receive list, that lets you listen additional talkgroups, on the same timeslice, at the same time. So, if you’re listening to a Local talkgroup, you must add a receive list that will let you listen to Central OK, and Statewide at the same time. This may let you hear what’s happening on this timeslice. This may also confuse the heck out of you. To keep this straight, you can read the front of the radio to be sure you know what you’re listening to. If this causes you grief, remove the receive list from the offending channels. Typically, it’s good practice to have a channel available that has a receive list with only the channel you are listening to, so you only hear the other party, and a channel that a fully populated receive list available, so you can hear what’s on the other talkgroups.
  • To keep your radio organized, set up a number of zones. One way to set up a zone is to have a different zone for each repeater. That way you can cycle through all of the talkgroups on a given repeater by twisting the knob. Another zone setup can set up zones by talkgroup. That way you can cycle through repeaters as you drive through an area. For example, if your OK State zone is set up, you can start in Norman, then twist the knob to OKC Downtown as you go north on I-35, then rotate to Edmond, Stillwater, and Ponca City as you head north. Other methods are also possible.
  • Scanning is allowed among the channels on a given zone. Remember that you can have analog channels set up, and that would let you can between the UHF analog channels, and various DMR repeaters and time slices. The downside of this process is that it takes an additional battery to make this happen. You’ll definitely see the battery drain quicker.
  • Codeplugs are personal. Your very first codeplug has enough to get you going. You’ll find that you work differently from the next person, and start making changes that match your use of the radio. Make sure you keep a copy of your codeplug on your computer, so you can reload this into a new radio as one appears.

Reflectors on DMR

The concept of reflectors was created specifically for use by DV4Mini hotspots since they didn’t have the ability to use proper talkgroups. D-STAR users are already accustomed to this idea and method of operation. Reflectors provide a dynamic way to attach to a specific talkgroup to the local talkgroup 9. The use of reflectors in DMR is not required. Every reflector connection can be made by simply selecting the proper talkgroup. On the DV4Mini hot spot, typically the radio is programmed to use the Talkgroup 4999, and then the user logs into the Brandmeister dashboard, clicks on their hotspot, and then they can change the talkgroup directly from that webpage.

A good example of this is that talkgroup 3100 is connected to reflector 4639. If you key up your radio on talkgroup 4639 and then move to another channel in your radio that is programmed to receive and transmit on talkgroup 9 you will be able to participate in conversations that are happening on talkgroup 3100.

If you transmit on talkgroup 4000, it will disconnect the current reflector from talkgroup 9. If you transmit on talkgroup 5000, it will read back the number of the reflector that is connected to talkgroup 9. In the example above you would hear four six three nine.

The repeater owner settings page, which each DV4mini operator would have access to, allows them to connect to a reflector without using the radio. There is also second setting, on the web page, which allows them to configure a default reflector to which your repeater return to after a given timeout period.

Repeater Coverage Maps

Maps of the coverage area for each repeater are available on the Brandmeister repeater pages. First, select your favorite repeater by searching for its callsign, or location. Then click on the name and you’ll get the repeater page for that machine. Scroll down to the map, and click on the little blue diamond in the top, right, corner of the map. A popup menu will appear as you get near. If you select the ‘Plot’ option, by clicking the checkbox, a coverage map for that repeater will appear on the screen.

Currently, Oklahoma repeaters have about 40 mile coverage circles, except for the North OKC repeater, and the service areas overlap significantly. There is pretty seamless coverage on the I-35 and I-44 corridors, with some missing coverage from Ardmore to Pauls Valley. The north OKC repeater is up at the 755′ level and provides about 100 mile coverage with a mobile radio.

More Information

More information may be available on the OK DMR Yahoo Group.

DMR, D-STAR, System Fusion Comparison

Powerpoint presentation display by Mark Kleine N5HZR to the SCARS meeting on April 9, 2016.