Columbus Ga DMR Information Page

Updated: 2/11/18

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(Listen Live to Columbus DMR)

DMR RADIOS TO AVOID!

 


 

First – Go ahead and get your DMR ID. It takes 2 minutes to apply and you will have your ID in  no more than a day! Click HERE to get yours.

DMR is not terribly different from what you are used to now on your current analog systems. You just have to learn a few new terms and a little bit different way to look at things.

First off. When you program, your radio, you need to put in the frequency for the repeater you are using, just like you do now. The frequency for the Columbus, Ga Repeater is 444.6125.
Your radio needs to TX on 449.6125 and Rcv on 444.6125.

On a normal machine, you would usually have a PL tone or CTCSS.
On a DMR machine, this is called a color code. The color code for the Columbus machine is color code 1.

Now we get into the differences.

Time Slots:
A DMR repeater has “Time Slots”

 

 

 

On the left is a typical analog signal. One transmission takes up the whole space.
With DMR your radio and the repeater slices the stream up in 30ms segments. One subscriber can be talking on TS 1 (The red segment) and one subscriber can be talking on TS 2 (The blue segment)

Your radio will be turning on and off every 30ms for 30 ms. This is so fast, you don’t miss the gaps. You and another person are sharing the stream in opposite slots. This also makes your battery last a LOT longer.

This is where assigning Time Slots comes in. The gentleman’s agreement is, always leave TS 2 open for local only traffic and TS1 is for all of the out of area stuff.

So when we program our radio, we will create our plug to use TS 2 for our local TG  and all of the channels we create for wide area stuff will use TS 1. I will show you all of this in detail later.

So we have the frequency, the color code and the time slot scheme. Once you learn the basics of programming your radio, these are all of the things you will need to program a plug for any radio on any repeater.

Talk Groups:

Talk Groups are nothing but fancy PL Tones. You and I must have the same “tone” programmed in to hear each other. Talk Groups are a way to control how many repeaters you key up when you talk. If you are on our local TG 311342, you will only key up our repeater. If you connect to any other TG, you will key up every repeater connected to that TG when you key up. The TG’s are organized by region or topic.

United States TG’s all start with 31.
The USA National group is TG # 3100
Georgia is TG # 3113
Region 4 is TG# 31094 etc…..
You can see a list of all TG’s here.

Just because you key up the Georgia TG, doesn’t mean you will key up EVERY DMR repeater in Ga. You will key up every repeater that is connected to the Georgia TG at that time. There are a lot of repeaters in Georgia that ARE connected all of the time, but our machine is not one of them. We only connect when we want to.

That being said, The name of the TG will indicate how many repeaters you will likely key up at one time. For instance, keying up National is going to reach a LOT of repeaters. Keying up Atlanta is going to… You guessed it, key up the Atlanta repeaters. I think you can see the logic here.

One more point on TG’s. When you connect a TG and you key up all of those repeaters, You will only be heard by people tuned to that TG as well. Now most people scan their repeaters, but you get the drift. You may key up 15 repeaters and never hear a soul, because they may be all close together and everyone is at work. ATL Metro would be one example.

You can see part of the list of TG’s in this radio program below. You can see how each group has an ID.

When you are ready to talk to an outside TG you:
1 – Scan the repeater to make sure no one else is using another group. Put radio in scan for a moment.
2 – Turn your radio to the channel you have saved with that TG info in it and give it a quick bump with the PTT button. (This connects the repeater to the TG) Ex. Turn to US National Group.
3 – Listen for a bit after key up to make sure no one is talking. (When you connect to a group and someone is talking, you may not start to hear audio until the next person talks)
4 – have your QSO.
5 – When done, Turn your radio to the “Clear Talk Group” Channel and bump the PTT. (This disconnects the TG from the repeater. Otherwise, it will stay connected for 15 mins until Time Out)

Each TG in your code plug is assigned to a memory channel with the TG ID number in it and the repeater info to access the TG. The repeater info will be exactly the same for every TG in your code plug the only thing that will change is the Name of the Group and what Group ID you are connecting to.
The only other difference will be the LOCAL talk groups will always use TS2 and any outside group will be assigned to TS1.
This is easy to do in your programming. You set up one local group and one outside group and then just copy and paste. Then you just change the name of the memory channel and pick which TG ID it is going to connect to.

You can see all of the info associated with a channel below.
Frequency,  bandwidth, time slot, scan list and what TG it ties back to called “Contact Name”

It all boils down to: You are steering the repeater with your radio. When you key up on a TG from your radio, it hits the repeater and says, “Hey, connect here” The repeater connects to that group and you are able to talk to anyone else in the world that is connected to that Group. That can be other repeaters or users on personal Hot Spots.

Again, groups are usually broken down by regions and some topics all around the world. You will have access to any groups you choose to use anywhere in the world just by simply keying up your radio.

Local Talk  Groups:

Local TG’s are just that. Local traffic only. I will have a link to the. 

When you are talking on the local groups, you will not be going out over any wide area connections. If you are talking to a wide area group, you will be heard by everyone on the National Group as well as anyone locally that decides to listen or participate in the wide area group. If it comes down to 2 local people talking on the wide area group rag chewing, please move to a local group to not tie up large networks.

ZONES:

In your radio programming you have “Zones”

Zones are like scanner memory banks. I typically make zones for each repeater I use.
Ex:
I create a Zone called SNDY  (Sandy Springs Repeater)
In that zone I place my memory channels.
I may have:
SNDY NA
SNDY WW
SNDY Tac 310

Alright, notice that each channel has SNDY in front of it.
You want to make a Channel for each TG for each repeater zone.
What that does is creates a channel for each TG with THAT repeater’s specific info in it. You have access to all of the same TG’s on every DMR repeater (Brandmeister registered ones) you may come across. The problem is, if you only program in one channel for each TG, when you were on another DMR repeater and tried to access that TG, you would have the Frequency info for the wrong repeater. That is why you make your TG channels for Each repeater.

Clear Time SLot or TG:

When you are done on a TG and want to turn it off you will have a channel programmed to TG 4000. When you turn your radio to this memory channel and bump the PTT, you will disconnect the repeater from the TG.

You will see in the above example that I have a channel called SHK Clear. That channel is in my Shark RF Open Spot zone or “SHK” zone. All my channels in this zone start with SHK. I have the SHK clear channel linked to the Group Clear contact. I can have many channels in many zones linked back to that one digital contact. Every repeater that I want to make a group clear channel on, I will link back to that group clear contact.

So in your radio, you will see a channel for Group Clear. This is the one you turn to to clear the group when done.

That is the basic for operation. Once you get your code plug installed you will:

1 -move to the Zone that has your repeater in it
2 – turn to the channel you want to talk on
3 – bump the ptt to connect to the TG
4 – Wait to see if it’s clear
5 – have QSO
6 – Change channel to “Clear TG”
7 – Bump PTT to clear

You can download sample code plugs HERE for our repeater. I will be glad to answer any questions you may have on modifying them or creating your own. 

Here are 2 graphics showing the basic network:

Local repeater view:

 

 

 

 

Wider view:

 

 

 

 

 

 

TG’s of Interest:

3199 Hurricane Net

Chris
WB4ULK

This is where I share my stuff for friends and family.