copyright 2015 cencal dmr digital mobile radio a.k.a. (mototrbo) a registered trademark of motorola...

Copyright 2015 CenCal DMR

http://www.cencaldmr.com

Digital Mobile Radio A.K.A. (Mototrbo) a registered trademark of Motorola Corporation

What is DMR


•Commonly known as Digital Mobile Radio•A standard for digital voice communications•Published by ETSI in 2005•Goal is: low cost, low complexity; and interoperability between manufacturers


The DMR Standard• Two-Slot TDMA

DMR Tier II/Tier III occupies a 12.5 kHz bandwidth with two channels sharing using Time-Division Multiple Access (TDMA)

• Digital Modulation 4FSK

• Vocoder agreed upon is AMBE +2 amongst vendors


The Benefits of DMR• Allows 2 simultaneous voice conversations using a single repeater like having 2

repeaters in 1 box• Improved audio performance over analog• More efficient use of radio spectrum vs. analog• +12 DMR radio manufactures = lower radio prices• Capable to being linked to over 800 other DMR repeaters worldwide


Range Improvement of DMR vs Analogue


How this all works getting stated

• Radio• Subscriber ID that uniquely identifies you as

being allowed on the greater DMR network• A understanding of the repeaters, their

talkgroup lineup the talk group ID and timeslots each talk group occupies as well as the repeaters color code. (a color code is to DMR what CTCSS PL is to analog)


What is a Talk Group

• It is a chat room within the repeater system that allows users connected with the same talk group to communicate.

• Can be networked• Can be non networked.• Typically we see repeaters hosting a total of 16

talk groups• They can be either active always or PTT


PTT vs. Active Always

• PTT – for example if you want to engage the feed for a particular talk group you simply key the repeater wait a second, then the repeater lis linked to the said talk group for a specified period in time then goes back to default.

• Active Always – The repeater has that particular talk group on all the time on a particular time slot. No user intervention required.


Why do we use PTT• We only have two time slots. If every talk group was active on and

you were communicating with someone on TS 1 and another TS 1 talk group keyed up you QSO would be ended for you.

• To not tie up the resources of the entire networked repeater system. Moving from a wide area talk group to a PTT is suggested for QSO lasting longer then 5 min.

• You start out on California when you key up you key up all 56 repeaters within the state. You are in LA talking to a station in Visalia the reasonable choice would be to move to a PTT talk group for example Cal 1. What happens is on each of the respective repeaters only that time slot and talk group is utilized so efficiency is greatly improved and it opens up the Timeslot on the remaining 54 repeaters to do what they want.


CenCal DMR Repeaters

Fresno (Bear Mountain) 442.2875 + 5.0Mhz Color Code 3

Visalia VHF (Park Ridge) 144.95 + 2.5Mhz Color Code 2

Visalia UHF (Park Ridge) 442.325 + 5.0Mhz Color Code 2

Clovis (Meadow Lakes) 440.0500 + 5.0Mhz Color Code 1

Visalia Low Level (KVIS) 442.3125 + 5.0Mhz Color Code 1


Talk Groups


Talk Group Talk Group # Time Slot #

Local 2 1

CenCal 1 - PTT 221 1

CenCal 2 - PTT 222 1

CenCal 236225 1

NorCal 5150 - PTT 5150 1

SoCal - PTT 76225 1

CAL 1 - PTT 2251 2

CAL 2 - PTT 2252 2

California 3107 2North America -

PTT 3 2

World Wide - PTT 1 2

TAC 310 - PTT 310 2

Southwest 3176 2

Audio Test - PTT 9999 2

Parrot - PTT 9998 2

Comm 1 3777215 2

CenCal DMR Talkgroup lineup


Programming

• How do you get 16 talk groups into one single channel?


Programming

• You Don’t!!!!!


Programming

• We program a bit differently then Ham’s are used to thinking.

• We make use of Zones (this can be the name of the repeater) the zone is a bank of channels

• We make use of Channels (these are included in the zone list.

• Each talk group is a individual Channel inside the zone with its own set of variables. On the same repeater what remains the same are: Tx Frequency, RX Frequency and Color Code


Programming

• What changes is:• The contact name, and the time slot the

contact name is.• What is the contact name?• It is your talk group assigned to that channel


Where do I go to get code-plug Primers to get me going

• http://www.caldmr.org• Under programming• Select sample code plugs• They have several available from: Motorola,

Hytera, and Connect Systems.• Make sure to put your subscriber ID in its

called Radio ID in most of the programs.

http://www.caldmr.org/


Where is DMR Today?

Chart courtesy of VA3XPR

• Coverage

• Less Resistance to Digital

• c-Bridge

• Fastest growing digital mode in North America

• CSI Radios


Where is DMR in California today?

56networked repeaters

190% growth rate year over year!

15% of U.S. DMR repeaters are here

in


California DMR Statistics!

672 unique IDs issued to California DMR users as of 1-13-15

10% of all global DMR users are right here!

Why are our numbers so high?


It’s the Coverage!


What’s in store?

Will continue to support and build out network.

Will place greater emphasis on interconnections and standardization

• Aligning Talk Groups– Time Slots, Always on, PTT

• Ensure Roaming is supported– Starts with talk groups, enabled, settings

• Continue to be a repository for information– Web, RF Coverage Maps, Yahoo! Group, Flickr

• Drive standards on radio and repeater programming– Sharing of info, Codeplugs

Continue to make it an easy mode for people to join and enjoy!


The END

• To download this presentation please got to:• Http://www.cencaldmr.com

copyright 2015 cencal dmr digital mobile radio a.k.a. (mototrbo) a registered trademark of motorola...

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