Digital Mobile Radio The very basics
Digital Mobile Radio The very basics John ‘Miklor’ K3NXU 2018 .
The DMR Difference History Audio Quality Spectrum Efficiency The Local and Worldwide Network Repeater vs. Hotspot Code Plugs DMR today in our area
Brief History DMR developed in Europe by ETSI European Telecomm Standards Inst Adopted as Commercial Standard 20 years ago Commercial Business Equipment Proprietary Equipment and Software High Cost Not ham radio friendly Ham Radio Equipment (2 years ago) Field Programmable Ham Friendly
Ham Friendly TYT MD-380 Motorola xpr7550 Single Band Single Band < $100 vs $500-$700 Anytone D868 Ailunce HD1 TID TD-9800 Dual Band Dual Band Single Band Features & Audio
Audio Quality Digital vs Analog TDMA
Spectrum Efficiency Analog FM = 25 kHz DMR (TDMA) = 12.5 kHz Tier I European License Free Band (not ham) Tier II TDMA Commercial & Ham Standard
Spectrum Efficiency – 30ms Time Slots
Time Slots Much like a Duplex House Two totally separate families in one structure. Time Slot 1 Time Slot 2 Each house has its own set of rooms (Talk Groups) Talk Groups
Talk Groups TG Time Slot Local 2 Local Cluster of Repeaters 2 Local 9 Main Repeater Only 9 TAC 310, 311 Secondary Chat Groups 310, 311 Nationwide National Calling Channel 3100 PA TAC Local Cluster of Repeaters 31421 PA State PA Statewide 3142 MD State MD Statewide 3124 NE Reg’l Northeast Regional 3172 Mid Atlantic Mid Atlantic Region 3173 Over 1100 Talk Group Possibilities ^
Talk Groups TG Time Slot Local 2 Local Cluster of Repeaters 2 2 Local 9 Main Repeater Only 9 2 TAC 310, 311 Secondary Chat Groups 310, 311 2 Nationwide National Calling Channel 3100 1 PA TAC Local Cluster of Repeaters 31421 1 PA State PA Statewide 3142 1 MD State MD Statewide 3124 1 NE Reg’l Northeast Regional 3172 1 Mid Atlantic Mid Atlantic Region 3173 1 FT / PTT
Talk Groups TG Time Slot Local 2 Local Cluster of Repeaters 2 2 FT Local 9 Main Repeater Only 9 2 FT TAC 310, 311 Secondary Chat Groups 310, 311 2 PTT Nationwide National Calling Channel 3100 1 PTT PA TAC Local Cluster of Repeaters 31421 1 PTT PA State PA Statewide 3142 1 FT MD State MD Statewide 3124 1 FT NE Reg’l Northeast Regional 3172 1 FT Mid Atlantic Mid Atlantic Region 3173 1 FT
Sample Repeater Configuration
Local 2
Local 2
Local / Worldwide Network 449.725 MHz (Shrewsbury) 447.275 MHz (Keystone) DMR Repeater Stand Alone System Can be IP Networked with c-Bridge
Local Network
National / World Wide Networks DMR Marc/Brandmeister
Networks Repeaters Direct Connect TG Compatibility
Networks Local 2 (Rpt) Local 9 (Rpt) PA TAC < > PA TAC 310, 311, 312 < > 310, 311, 312 313 > 319 x 313 > 319 State Groups < > State Groups Regional Groups x n/a Nationwide 3100 < > Nationwide 3100 Repeat vs Hotspot
Repeater vs. Hotspot Repeater’s provide both Local and WW area coverage Hotspot Replaces a Repeater Very short range Brandmeister But Why ?
Why use a Hotspot ? No nearby repeaters Heavy traveling Long Conversations So, where’s the activity?
1500 Talk Groups – Your Choice
Activity Levels TG Activity Local 2 Local Cluster of Repeaters 2 Low FT Local 9 Main Repeater Only 9 Low FT SPA Local Keystone & Shrewsbury only 31425 Low FT PA TAC Local Cluster of Repeaters 31421 Low PTT PA State PA Statewide 3142 Med FT MD State MD Statewide 3124 Med FT NE Reg’l Northeast Regional 3172 Med FT TAC 311,312 Chat Groups 311, 312 Med PTT TAC 310 Main Secondary Chat Group 310 High PTT Nationwide National Calling Channel 3100 High PTT Op Notes
Operating Notes 3 second pause before PTT Network Latency Courtesy Pause 1 second pause after PTT Channel Busy Radio needs to sync to DMR signal Time Slot in use Green Light Time Slot busy tone Someone on same TS but different TG Talk Group in use You may not immediately hear an active Talk Group
Operating Notes Dash Boards Avoid Calling CQ This is not HF. There is no DX, WAS, etc. Announce your talk group Scanning or radio without a display Avoid long QSOs on wide area talk groups Please move to a TAC channel Time Slots Each Time Slot will only support one QSO at a time. regardless of the number of talk groups available. Dash Boards
Dashboards Netwatch Watch the DMR Network activity Real Time Hoseline Listen to Brandmeister Talk Groups Real Time
Netwatch
Hoseline
Dashboard Links Netwatch http://cbridge.wr3irs.com:2135/MinimalNetwatch Allows you to view DMR network activity Real Time Hoseline http://hose.brandmeister.network/group/91/ Listen to Brandmeister network talk groups Real Time Miklor.com K3NXU.com (DMR Section) www.miklor.com/DMR/ www.K3NXU.com
Reference http://www.Miklor.com/DMR/
Code Plug FM Frequency / CTCSS DMR Frequency / Color Code Three Main Divisions (1) Contact List (Talk Groups) (2) Create the Channel Information (3) Group the Channels into Zones
Code Plug Step 1 - The Contact List aka Talk Groups This is where the Talk Groups are stored. - Talk Group Name - Talk Group Number - Group or Private (Select Group)
Code Plug Step 1 - The Contact List aka Talk Groups
Code Plug Step 2 - The Channel Information Mode Digital Frequency Rx and Tx Color Code 1 Channel Spacing 12.5 kHz Time Slot Whatever was specified for the repeater Tx Contact Talk Group from Contact List Rx Contact “None” will default to the Tx Contact Power High or Low Tx Criteria “Always”, Color Code, Channel Free Scan List Optional
Code Plug Step 2 - The Channel Information
Code Plug Step 3 - The Zone This is where you assign your favorite channels to a cluster or channel bank. They can be grouped by: Repeater Location Activity Analog Repeaters Simplex etc. You can mix and match. The choice is yours.
Code Plug Step 3 - The Zone
Code Plug Step 4 - Scan Groups This is where you create a group of receive channels that you would like to Scan. Assign the Scan Group to a specific channel.
Code Plug Step 4 - Scan Groups MD / PA
Code Plug Step 4 – Scan Groups
MD, PA Cluster May 2016 44000 Registered DMR IDs 333 in PA May 2018 96000 Registered DMR IDs 1400 in PA 600 in MD 100 in DE Oct 2018 112,000 Registered DMR IDs
DMR in the USA
DMR in the Mid-Atlantic
V = VHF U = UHF * = Limited Coverage ** = Coming Soon MD, PA Clusters (Local 2) V = VHF U = UHF * = Limited Coverage ** = Coming Soon
MD, PA Clusters