Digital Simplex in Washington


PNWDigital.Net is working toward adding DMR simplex to our community codeplug that will support the new WWARA sanctioned digital simplex frequencies and pairs.  As part of that project, we have roughed out 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. IACC is expected to adopt the WWARA plan so this would be the same across the state.

The table below contains the the recommended defaults for the 8 simplex frequencies and 4 duplex pairs.

Ch Label

Simplex Duplex +9 Notes
Sim V1 145.7900   Simplex Defaults are: TG ID #99, Timeslot 1 and Color Code 1, talk permit Always

If you create your own non-defaults, please add them to your zone so that the defaults are available

Original Simplex frequencies implemented in 2014 by worldwide consensus

Sim V2 145.5100  
Sim U1 441.0000  
Sim U2 446.5000  
Sim U3 446.0750  
Sim U4 433.4500  
Sim U5 WA 430.4125   WWARA recommended low power (non-protected)

 5 watts is the recommended maximum power

Sim U6 WA 439.4125  
Sim U7 WA 430.4250  
Sim U8 WA 439.4250  
Rpt U9R WA   430.4375 +9 Repeater 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 U10R WA   430.4500 +9
Rpt U11R WA   430.4625 +9
Rpt U12R WA   430.4750 +9

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.

Additional thoughts or concerns that may merit further discussion:

As you can see, there are 10 simplex freqs, 4 duplex pairs, 2 bands, 1 timeslot and 1 talkgroup. We suggest that we try to develop a plan that be acceptable for use in our region that expands from this basic list with the effort 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.

Just some 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)



 Revised: 10/23/2020 09:04


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