W4RAT DMRVA C-Bridge Repeater

RATS operates a Digital Mobile Radio (DMR/MotoTRBO™) repeater as part of the DMRVA system which covers most of Virginia.  This repeater went into service on May 30, 2014 with the generous assistance of Jay Lovelady KD4BPZ and Dave Meier N4MW.  This Motorola XPR8300 was originally placed in service on a backup UHF antenna at around 465 feet.  It spent 2020-2022 at 680 feet.  It's currently using an antenna at 580 feet.  And it'll move again, back to 465 feet, if/when we reinstall a backup VHF antenna at that 580 foot position.  Transmitter power was given a boost from 20 to 25 watts (full power) in July 2023 when this repeater was reinstalled following a nearly one-year hiatus.

Like the rest of the W4RAT repeater systems, the DMR repeater and its network connectivity are serviced by emergency battery and diesel generator power.

Before going on the air, repeater users should be familiar with the particulars of DMR operation, as well the RATS Repeater Rules & Policies, basic repeater etiquette, and some general talkgroup etiquette from our friends at DMRVA.  You must also transmit a valid DMR radio ID.  If you need help becoming familiar with DMR or have questions about operating procedures, please contact the RATS Elmers.  We will be happy to help in any way we can.  If you make regular use of the system, please consider club membership or a donation to show your support.

Planning to use a DMR hotspot?  Read this first.

Questions about the DMRVA network, including requests relating to nets or special events on a DMRVA member repeater, should be directed to DMRVA.  Questions about the RATS DMR repeater specifically may be directed to our Technical Committee.

Here's an estimated coverage map generated with Radio Mobile Online by Rouger Coudé VE2DBE.

Basic Configuration

Frequency:  443.5875 MHz, +5 MHz offset
Call Sign:  W4RAT
Mode:  DMR Tier II, fully digital (two time slots)
Parameters:  Color Code 1
Repeater:  Motorola XPR8300
Antenna:  unknown UHF antenna @ 580 ft
TX Power:  25 watts

Network Status and Traffic, Audio Streams

You can listen to select talk groups online.

See current system activity with Call Watch.

Network status for the DMRVA portion of the network can be viewed on Peer Watch.  This page explains how to read Peer Watch.

"Private" Calls

Please use time slot 1.

While use of the public talkgroups is encouraged, direct one-to-one voice calls between radio IDs are permitted on the W4RAT repeater.  Note that contrary to their name, private calls can still be easily heard by others -- there is no actual privacy.  These calls do not propagate out to other repeaters, except the Petersburg machine.

Similarly, Call Alert and Radio Check only function within the RATS and Petersburg repeaters.

DMRVA & HEARS Repeaters - Talkgroup List

As of August 27, 2024.  Click here for coverage estimations.

Talkgroup matrix notes:

CC = color code. Either 1 or 9 is used on repeater sites.

UHF repeaters frequency offset is + 5Mhz.  Listed frequency is repeater transmit.  Enter this frequency as your mobile/portable receive frequency.

Frequency offset is -600 kHz for Fredericksburg VHF.  Listed frequency is repeater transmit.  Enter this frequency as your mobile/portable receive frequency.

Frequency offset is +600 kHz for Salem (Fort Lewis) VHF.  Listed frequency is repeater transmit.  Enter this frequency as your mobile/portable receive frequency.

"On" means the talkgroup is always connected.  There is no need to "kerchunk" to activate this talkgroup.  Where a number is shown -- either 5 or 15 -- this is the inactivity timeout for on-demand talkgroups.  Try to remember to use the Clear Timeslot function when you are done using any of these channels.

Colors for 27500 indicate local TG's that are connected together.  Gray is local only. 27500 may have name variations (i.e. Richmond Metro, Rapp Regional, etc).

Richmond Metro is also available through the Brandmeister network on 31511 and PTT on Spotsylvania repeaters TS1 TG 31511.

Roanoke Local is also linked to Brandmeister Long Ridge site (BM TG 315136).

Echotest is available on TG 9998 and 9999 (group call). Both enabled to make transition from N4HRS to DMRVA easy for users.

Codeplugs

High quality, pre-built DMRVA codeplugs are available for a wide variety of radios through the RATS Codeplug Project.

DMRVA Repeater List and Site/Zone IDs

For additional information see the RATS Codeplug Project.

DMRVA+HEARS Combined System Map

Orange = Richmond Metro cluster repeaters
Yellow = Richmond Metro portable repeaters - home locations
Blue = DMRVA and HEARS-VA networked repeaters

Static Talk Groups

Our two static talk groups are Richmond Metro and Virginia Statewide.  These two talk groups are always active.

Dynamic Talk Groups

All other talk groups are dynamic, or "PTT-controlled."  They're only active when needed.  Most of the time you will not hear any traffic on these talk groups.  While the repeater will allow more than one simultaneous dynamic talk group to be active, this will produce unpredictable and usually undesirable behavior.  Here are some best practices for using dynamic talk groups:

Best practice:  Have a channel configured in your radio to perform a "monitor all" or "scan" function on all talk groups to ensure nobody else is currently using a dynamic talk group.  You'll need to set this up in advance using your radio's CPS.  Listen for a reasonable amount of time (10-15 seconds).

Select the desired talk group, briefly press the PTT key.  (Here's the official word from DMRVA on kerchunk-control.)  This kerchunk will activate the talk group.  Because talk groups are shared with other repeaters on the network, you will again need to wait several moments to begin hearing any distant traffic that may already be taking place on that talk group.

Hearing no traffic on that talk group, make your call.  It's a good idea to say which talk group you're calling on because the receiving station may have their radio in a scan mode.  "AB1CDE, this is K4ABC on Virginia Southwest"

When you are finished with your QSO, transmit your call sign to the "Clear Time slot" talk group.  This will deactivate the dynamic talk group and free the repeater for another user.

Dynamic talk groups are on a timeout and will deactivate if there is no local traffic (that is, no transmissions coming in to our repeater) for 15 minutes (5 minutes on TAC A and TAC B).  You will need to transmit to the talk group to reactivate it after timeout.  If you have a special need for extended access to a dynamic talk group, consider the use of a DMR hotspot device instead of the repeater.

Receiving a Call on a Dynamic Talk Group

If you are expecting a call from someone on a different repeater (including another DMRVA repeater) using a dynamic talk group, you will need to already have the talk group active in order to hear their incoming call.  Follow the procedure described previously for activating a dynamic talk group.  Of course, if you're the one initiating the call, the distant party will need to have done the same, otherwise the talk group will not be active on their end.

Locals and Metros

The Local talk group (27500) works a little different depending on which DMRVA or HEARS repeater you are using.

In many instances, the Local talk group is shared across multiple repeaters.  When more than one repeater share a Local talk group, we call this a Metro talk group.  When you transmit into Metro, you are coming out of multiple repeaters in your area.  The talkgroup number is unchanged across all repeaters - 27500. 

The table to the right shows the arrangement of DMRVA Local and Metro talkgroups as of August 2024.