The Basics of DMR

What are Talk Groups & Reflectors?

HVDN Local Information

Here are some popular talk groups in the Hudson Valley that are part of the preferred DMR technology adopted by the HVDN.


To find out which repeater carries what talk group or where to find local non-repeater activity, please look at our HVDN repository here.


TG in Bold with a * are the official HVDN  talk groups for local and internet  use. 


TG 31360 = NY/NJ/PA Tri State

TG 31361 = Upstate NY

TG 31362 = NY Metro 

TG 31363 = Adirondacks Region

TG 31364 = Lower Hudson Valley

TG 31365 = K2MAK System

TG 31366 = NY Metro ARES

TG 31367 = Southern Tier NY State

*TG 31368 = Mid Hudson Valley*

TG 31369 = Rochester Area

TG 3100 = USA Nation Wide

TG 31091 = ME, VT, NH, MA, RI, CT

TG 31092 = NY & NJ

TG 3172 = North East US

TG 3181 = New England

TG 3109 =  Connecticut 

TG 3125 = Massachusetts

TG 3134 = New Jersey

TG 3136 = New York

TG 3142 = Pennsylvania

TG 3150 = Vermont

TG 4326 = Canada

TG 4593 = Ontario

TG 310  = TAC 310

TG 311 = TAC 311

*TG 312 = TAC 312*

TG 2 = Local repeater Only

TG 8 = Regional repeater

TG 9 = Local Repeater or Hot Spot

TG 99 = Simplex

TG 113 = User Activated 113

TG 123 = User Activated 123

TG 119 = User Activated 119

TG 129 = User Activated 129

TG 1 = World Wide

TG 3 = North America

TG 444 = Bronx Turbo Local

TG 7388 = LIMARC Local

*TG 1888 = Mid Hudson TAC*

TG 8801 = New England TAC 1

TG 8802 = New England TAC 2






What Is A Talk Group?

A talk group is an address that allows all stations to communicate together who are set up on the same talk group, much like how the US Postal Service uses ZIP codes and addresses to route mail.


There are different organizations that are trying to bring uniformity to talk groups so that if you are set up on talk group 3136 anywhere in the world, you will be connected to anyone else who expects 3136 to be the New York statewide talk group as an example. 


Some of the organizations tasked with this mission include Brandmeister, DMR-MARC and DMR+.  


HVDN is looking to help coordinate and add resiliency for just the Hudson Valley area repeaters.


An important thing to know about a talk group is that it is administered locally and there are certain ranges of talk groups that may have a different use from one area to the next, but the majority of them are the same all over the world now since DMR is the fastest growing and most used digital voice technology globally available to amateur radio operators. 


Here are some examples of talk groups:


3100 = United States Nationwide Calling 4400 = United Kingdom National Calling 4800 = Australia Nationwide Calling

4750 = Belgium National Calling 


9 =Local discussion on a repeater not routed over the internet.


A complete list of talk groups can be found in various locations and the goal of HVDN is not to provide this, but accuracy of local talk groups of interest in and around the Hudson Valley. 


We do however provide a file in our "Generic & Other Code Plugs" section of the HVDN repository










What Is A Reflector?

A reflector is different than a talk group in that its function is to allow different DMR networks to talk to each other with some level of uniformity.


Example based on talk group 3100 which traces its origin back to the early days of the DMR-MARC network is that there was no way for other non-Motorola based talk groups to communicate to other networks such as Brandmeister or DMR+. 4639 is a reflector that "bridges" together the Brandmeister and DMR-MARC networks.  


A reflector is always based on needing the internet to work. If the internet disappeared which is not likely, so may reflectors.


Here are some reflector examples:


USA Wide TG 3100 = REF 4639

North East US TG 3172 = REF 4642

North East US TG 31092 = REF 4642


Its not perfect, but between talk groups and reflectors there is much more capability compared to other digital voice options such as  Yaesu Fusion, and Icom D-Star.



DMR even allows two discussions to take place at the same time on the same frequency based on TDMA technology. No other existing amateur radio equipment has this capability when deployed correctly.


DMR also takes advantage of being an open standard which may excite computer enthusiasts familiar with open source software who may want to get involved with amateur radio and create something interesting. 


Reflectors should function to tie in smaller geographic areas into a larger one or perhaps focus on a broad topic like "embedded computing" or "software defined radio" or "camping & hiking"