Notes from Monday Night FreeDMR Net 27th March 2023

Facilitated by the Brisbane Amateur Radio Club A successful net was help Monday 20th March 2023 0900 UTC. Once again Les, VK4LEZ did a great job as net Controller. The topic of antennas was discussed.

Click on [FreeDMR] for the FreeDMR Pages.


  1. VK4LEZ Les
  2. VK4PK Glenn
  3. Vk4MPS Karl
  4. VK4DMB Doug
  5. VK4DU Glenn
  6. VK4JP Lindsay
  7. VK4VVK Lin
  8. VK4ANB Norm
  9. VK4NSP Shaun
  10. VK4GCR Ralf
  11. VK4CEG Graham
  12. VK4EHT Bruce
  13. VK4FDPM Damian
  14. VK4BUL Bill

A New Facebook Page: 505-FreeDMR

We have a New Facebook page 505 FreeDMR thanks to Glenn VK4DU. Sign in now at and Glenn will welcome you aboard. This page is dedicated to FreeDMR in Australia and great place to exchange information as wel as your thoughts and ideas.

This group is designed to bring together all Australian radio amateurs who are interested in the FreeDMR network. Why 505? 505 is the DMR country code for Australia and also is the number of the main Australian FreeDMR talk group.

Much more content is in the way.

The Motorola Repeaters

Further fine tuning adjustments are being made to the interface to Motorola repeaters on the FreeDMR network. Motorola repeaters expect the server to implement most of their functionallity (everything goes to the server for processing), so the server needs a “container” that includes a replication of a MMDVM command line.

Observations on Talk Group Behaviour

Bruce's code plug for 5050 has it on TS1. Graham VK4CEG was on TS 2 so Bruce could not hear him on VK4RBA. but could see the dashboard & change to TS2 to communicate. If Lin VK4VVK (on TS1) did not hear Graham (& vice versa), that would be why.

We are trying to understand how FreeDMR handles TG's. FreeDMR has no fixed Talk Group matrix like some other networks. FreeDMR allows you to freely select any TG. For example I transmit on TG5050-1 on repeater A and repeater B has TG5050-2 then it will receive me on TS 2. I have read that the TS property is only known between the radio and the repeater. The network and the server to server (reflector) traffic has no knowledge of the TS property.

Now if we consider a single repeater there is no consideration of network traffic. All communication is done on the one repeater. Thia has been tested between statuions that have been blocked on the VK-DMR Network and prohibited from reflector traffic. Two blocked stations can communicate freely as long as they are on the same repeater. Single repeaters do not "need" the network to communicate.

Question 1: In this single repeater scenario if I transmit on TG5050-1 and another station has activated 5050-2 will that station receive me?
Question 2. If I transmit on TG5050-1 and TG5050 is set static on TS 2 on this repeater will a station on TG5050-2 receive me?

The answer to both questions appears to be No.

Bruce VK4ETH, has undertaken some experiments:

Experiment 1:

  1. I Transmitted on 5050 to my hotspot (ie net work to RBA) and RBA sends it out on TS2
    (I undersatnd that is TG5050 is static on TS2)
  2. I Transmitted on RBA on TS2 and it is output by my hotspot (as expected)
  3. I Transmitted on RBA on TS1 (activating TG5050 on TS1) and it is output by my hotspot (as expected).
  4. It outputs from RBA on TS1 but not on RBA TS2 eg there appears to be no connection internally
    or via the network between TS1 and TS2.
  5. I then transmitted to my hotspot on TG5050 (net to RBA) and RBA outpus on both TS1 and TS2.
Experiment 2:

Now I complicated things using Dail-a-TG. On RBA Dial-a-TG only works on TS2. If you try on TS1 you don't get the "Connnected to ...." message. With Dial a TG freshly set up to TG5050 (on Ts2). If you then transmit on TG9 you go out on the network as TG5050 and incomming signal on TG5050 are output on TG9 TS2 (as expected) (a bit shaky now) If you activate TG5050 on RBA TS1 (where it is not static) the unexpected happens. The previously set up Dial-a-TG on TS2 seems to deactivate. I was trying to recreate the situation that I remember seeing during a net where RBA either randomly or due to time out on either TG5050 or TG9. I was reporgramming my radio on the fly so I could have made errors. I'll set up a zone with just the channels I need to test further. It seems a repeater will repeat locally received TS & TG via RF ahead of any network/server traffic. A standard repeater does not repeat from one TS to the other. (even if you think it might happen via a server). I understand that a specially set up repeater (single frequency repeater) can be especially made to do this.

Expirment 3: A little more controlled this time. I used Droidstar to simulate someone somewhere else on the network:
  1. Transmitted on Droidstar TG5050 and the output from VK4RBA TS2 (proves TG5050 is static on TS2)
  2. I setup TG5050 active on VK4RBA TS1 & test both ways to Droidstar(Droidstar TG5050)
  3. I setup Dial-a-TG to 5050 on TS2
  4. Transmitted on VK4RBA TS1 TG5050 to Droidstar ok
  5. Transmitted on VK4RBA TS2 TG9 to Droidstar ok
  6. Transmitted on Droidstar TG5050. RBA passes TG5050 TS1 and TG9 TS2
  7. I repeated steps 3,4,5 same result
  8. Transmitted on rf to VK4RBA TG5050 TS2. Droidstar receives TG5050
    (this I thnk is where dial a TG has been overidden by reactivating TG5050 or resetting static TG5050)
  9. Transmitted on Droidstar TG5050. VK4RBA broadcasTS TG5050 on both TS1 and TS2
  10. Transmitted on VK4RBA TG9 TS2 . TG9 repeated locally only. Nothing on Droidstar. (Dial a TG seems to have been cancelled).
  11. At no time did any transmitted RF into VK4RBA cause it to transmit anything other than the same TG & TS.

Shaun VK4NSP Request

Shaun VK4NSP has requested you keep a log of issue on FreeDMR along with time of day and the access method eg hotspot or Repeater name. They can be posted on the 505-FreeDMR facebook Page.

Quick Links to Dashboards

There are many choices of Dashboards with FreeDMR. Each server has its own dashboards and then any MMDVM Repeater will have a PI-Star Dashboard. So there are basically two types of Dashboards, FreeDMR Servers type and the Pi-Star type. They are quite different in the way they present data. As to which is best is a matter of private opinion. I am currently using the FreeDMR-Australia Server so I have one sceen open on this and I am transmitting via the VK4RBA Repeater so I have it's Pi-Star Dashboard open on a For more details see: Dashboards Explained

FreeDMR has Many Servers

REMEMBER that FreeDMR has many servers to choose from (three in Australia) and each may be configured slightly differently. Each Repeater or Hotspot can connect to any of these servers world wide, can also be configured differently. Try to be aware of these differences. For example, FreeDMR allows you to configure Talk Groups as you see fit. (Where you have administration rights. For example, your hotspot.) There is no matrix to say what TG's are allowed or to specify a time slot.


In common usage kerchunk definition is, "with a sudden heavy blow or thump". (Wiktionary) For amateur's in general the term kerchunk means to key up the repeater to see if it is there. For amateur's in the digital world is means to open a User Activated repeater to gain service.

It just takes a few seconds on Push-to-Talk (PTT) button on the transceiver to user activate most repeaters, resulting in a kerchunk sound. Then the successive Push-to-Talk's will allow communication to occur until the timer expires which is configured on the repeater or the hotspot you are accessing. This is usually 10 to 15 minutes.

Frequently Asked Questions

If you have some unanswered questions you may find the answer here: Frequently Asked Questions
Do you have a question? Email any questions you my have to and we will see if we can answer them for you.

The FreeDMR Pages start here: [FreeDMR]

Glenn Lyons VK4PK