PNWDigital.Net has added DMR simplex support to our community codeplug. It supports the new WWARA low power, “unprotected” digital, narrow-banded simplex frequencies and duplex (repeater) pairs.  IACC is expected to adopt the WWARA plan so this would be the same across the state of Washington.

This project now lists the DMR simplex plan which incorporates the long standing 6 national and international DMR simplex frequencies in 2 meters and 70 cm as well as the WWARA’s recent adoption of non-protected low power digital simplex frequencies and duplex pairs.

The table below contains the the suggested labels to use as well as the recommended defaults for the 8 simplex frequencies and 4 duplex pairs. This appears as a zone and channels in the PNWDigital Anytone Community Code Plugs also.

Channel LabelSimplexDuplex
+9 Mhz
Sim V1145.7900 Simplex Defaults are: TG ID #99, Timeslot 1, Color Code 1 and Talk Permit: Always
Simplex frequencies implemented in 2014 by worldwide consensus
Sim V2145.5100same as above
Sim U1441.0000 same as above
Sim U2446.5000same as above
Sim U3446.0750 same as above
Sim U4433.4500same as above
Sim U5430.4125 WWARA recommended low power (non-protected) 5 watts is the recommended maximum power
Sim U6439.4125same as above
Sim U7430.4250same as above
Sim U8439.4250same as above
Rpt U9R 430.4375Repeater default talkgroup: Local 1, TGID # 3181
Repeater input is 9 Mhz above the output.
Set talk permit to follow color code (MotoTRBO use: TXI)
5 watts is the recommended maximum power
Inputs and outputs may be reversed, suggest that for dedicated repeaters, that different color code be used to minimize interference generally as well as at events specifically.
Rpt U10R430.4500same as above
Rpt U11R430.4625same as above
Rpt U12R430.4750same as above

We suggest that if you make changes, that you add your changes to a simplex zone rather than modify these defaults.  This will ensure that everyone has a standardized set of simplex for traveling or when at events such as the Valley Camp, Mic and Key, etc.

NOTE: The following frequencies are now reserved by SCRRBA in Southern California, so these may be additionally considered for low power digital simplex: 431.1125 / 431.1250 / 431.1375 / 431.1500 / 431.1625 / 431.1750 / 431.1875

Additional thoughts or concerns that may merit further discussion (historical)

As you can see, there are 8 simplex freqs, 4 duplex pairs, 2 bands, 1 timeslot and 2 talkgroups.  We suggest that we try to further develop a plan that be acceptable for use in our region that can expand from this basic list to address efforts which allows simultaneous use of multiple frequencies and then break it down for use by single-slot, talkgroup ID’s.  We think that Color Code defaults should be #1, the standard.  This could be the beginning point of the discussion.

We should likely factor in for higher level portable operation, with or without Internet connectivity for use of cross-slot simplex, 1 and/or 2 slot hotspots as well as cross mode or band operation as one might find in a typical Go-Box for hilltops.

More for other baseline thoughts for this discussion:

  • UHF or VHF propagation considerations
  • Why use Color Code 1 and not use others
  • What TG’s would be best; Simplex 99, TAC’s, Statewides or new discrete simplex only
  • Timeslot considerations, simplex may be single slot or dual slot, many radios don’t support all the options
  • Frequencies; determining them; splinters, single or dual slot (6.25 or 12.5)

First Published: September 26, 2021 Last Updated: 2 years ago by Dave – W7NCX

Views: 433

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