Special Event TAC C

There are two public TAC channels on the DMRVA network -- TAC A and TAC B. Anyone can use these two channels.

In 2024, a third TAC channel was established on select repeaters, utilizing timeslot 2.

► TAC C is available on the Richmond (RIC), Petersburg (PBG), and Portable repeaters (POR) only.

► This is a closed-access talkgroup intended for emergency overflow use at public service events.

All use of TAC C requires prior authorization. Authorization is usually granted to events, not individual radio IDs, so all participating stations may utilize that talkgroup for the duration of the activity. The RATS Technical Committee serves as a point of contact for TAC C access requests, or you may contact DMRVA directly.

To better support adoption of DMR for public service events in the metro Richmond area, TAC C is included in RATS codeplugs beginning with version DMRVA2.6.

Why is TAC C restricted?

The DMRVA talkgroup matrix places local and regional traffic on timeslot 1, including TAC A and B. Under most conditions, one timeslot and the standard DMRVA talkgroups are plenty adequate to handle radio traffic from the average public service event. Unexpected circumstances may cause congestion on timeslot 1. TAC C provides temporary relief with access to additional network capacity on timeslot 2 without occupying a statewide talkgroup.

Normally we want to keep timeslot 2 free for wide-area traffic on VA Statewide and HEARS Link. TAC C is not intended to handle routine radio chatter.

TAC A and B are publicly available on all DMRVA+HEARS network repeaters in Virginia as PTT-activated talkgroups.

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