Best Practices


To familiarize everyone with the power of DMR I want to point out a few limitations of the system.  The repeater is a 2 time slot TDMA meaning one frequency occupies a total of 12.5 KHz of bandwidth +6.25 and - 6.25 KHZ of frequency center.TS 1 occupies a total bandwidth of 6.25Khz in 20 ms bursts while TS 2 occupies a total bandwidth of 6.25 Khz in 20 ms bursts.  

This equates to we can have one conversation occurring on one time slot at the same time another is occurring on the opposing time slot at the same time without each party being aware of the others existence.  Translation one repeater in DMR works like 2 analog FM repeaters.   To that end it is important to note we only have 2 time slots and we are a wide are linked repeater system with many of our hill tops sharing common talk groups which allow for interconnectivity of the greater California DMR network.   

With that said we have active always or static talk groups and user activated or dynamic talk groups.    On each of our repeaters the Static talk group on Time Slot 2 is Mtn West and the Static Talk group on Time Slot 1. This talk group is distributed to Alameda, Meadow Lakes, Bear Mountain, Park Ridge Look Out, Blue Ridge, Down Town Fresno, Santa Rita Pk, Bakersfield, Victerville, Wrightwood; Santiago Pk, Johnstone Pk; and lastly Chuckwalla located near desert center near Blythe. The Time Slot 1 TG that is Static is California which has approximately 89 repeaters statewide tied together. It is important to note that all other talk groups are Dynamic or user activated.  How this works is if a dynamic talk group is keyed on either talk group all traffic on that Time slot is held off for 15 minutes of inactivity then the systems returns to its configuration.  

With that said many of you utilize the Mtn West Talk group for extended periods of time; many of you use the same repeater.  If you are on the same repeater, use Mtn West to establish comms if your QSO lasts for longer then 5 minuets as a courtesy to others that may want to use the time slot for other talk groups move to Local or the dynamic TAC version of Mtn West which is Mtn West 1.   If you are on two different systems please move your conversation to the dynamic Mtn West 1 it only ties up the repeater you are on and the repeater the other party is on making the system more flexible and usable to users that may want to check into a net that share the same time slot as you are on.  

I realize this is new technology to many and we don’t completely understand how to harness the full potential of the system but I wanted to point out a few nuances that may help everyone enjoy and have fun at the  same time.  


The reason why I mention this is on Thursday a member wanted to check into the NorCal net on Time Slot 2 at 8pm and couldn’t because California on TS 1 was gussied out as Well As Mtn West on Time Slot 2.  The end result was he couldn’t listen to the net or check in which led to his frustration.   I asked the question of the group about taking California to Dynamic and the ovrerwealming majority of you said no so to that end I am drafting this email not to admonish anyone but to enlighten each and everyone of you how the system can be leverage for its maximum efficiency and utilization.

Below is a list of the Dynamic Talk Groups and their Time Slot.

Mtn West 1 TG ID 31063 Time Slot 2 Mountain West (Central California and High Desert)
Nor Cal 1 TG ID 31069 Time Slot 2 Northern California
So Cal 1 TG ID 31067 Time Slot 2 Southern California

California 1 TG ID 31061 Time Slot 1 State of California
Tac 310 TG ID 310 Time Slot 1 Nation Wide


Thank You

Mountain West DMR