Monday, March 11, 2019

Ham Ninja’s DMR Tip 0, How to Get DMR Repeater Info

I'm starting a Digital Mobile Radio (DMR) tips series.  In the spirit of being digital, I thought I would start with post 0 (zero).  In this installment, I’ll cover one of the most important things you should know how to do, getting important details about about a repeater that you would like to use.  Obviously, you need to know how to connect to it like any other repeater, but you can get a lot of other great information that is very specific to DMR.  This includes things like what DMR talk groups the repeater is subscribed to all the time (static talk groups),  or how busy the repeater has been, or what timeslot you should use for groups that are configured on it.  All of this information is LIVE!
(NOTE:  If you don't know what DMR is, take a look at my post "DMR Defined")

[  The numbered lists below help give you a tour of the page by referring to numbered spots acting as landmarks on the example page in each section.  Also: Click on images for a larger version.  ]

Finding a repeater

The first thing you will want to do is search for a DMR repeater.  The first page, Figure 1 below, shows a list of repeaters from a query that I entered.  You can search using the call sign of the repeater, name, frequency, as well as other data.  In my example, I searched for the Qualcomm repeater by entering “qualcomm”.  
[The numbers on the related figures are meant to go with the numbered list in each section]

  1. After the page loads, click on “Repeaters” in the left column.

  2. Enter your query in the search text-box.

  3. Repeaters are listed with links to the repeater info page.

It may take a few seconds while the page loads all the data but once complete, the page will be filtered based on your query and very responsive to new queries.

Click on the entry “AI6DZ Qualcomm” to open the repeater info for this repeater.  Continue reading to learn more about what you will see here.

Figure 1 (click on image for larger)

[  Bonus Points: Search for all of the Papa System repeaters by entering “papa” into the query page.  ]

Using the repeater info page

After selecting the repeater you want to view, you should be looking at a repeater configuration page similar to Figure 2 below.  

  1. In the first section on the left column, you’ll see some basic information about the repeater ID, where it’s located, a link to the organization's website, operators or sysops, and type of hardware, power, and it’s current status and what Brandmeister master server it’s connected to.  Most of this info is a FYI.

  2. This next section down on the left is the Frequency section.  The frequencies are the frequencies that the repeater uses.  Be careful, they are labeled differently than  For example, because this repeater transmits (TX) on 449.4625, you should set your radio to receive on this frequency and set your radio to transmit on 444.4625.

  3. The “Slot details” section display what talk groups the repeater is currently subscribed to on each time slot.  The most important thing to pay attention to are what talkgroups are “static” on this repeater.  Static groups are setup by the repeater owner and are always repeating any traffic heard on that talk group on the indicated timeslot.  Static talkgroups have a small padlock icon on them.  If you can't see them, click on the image for a larger version.

    This section also shows “dynamic” talkgroups.  Instead of a lock, they are a different color and have what looks like a lightning bolt on them.  These are talkgroups that users have forced the repeater to subscribe to by transmitting to the talkgroup on the repeater.  The talkgroup is active on the repeater for 15 minutes after the operator transmits.  The expire time is reset each time an operator transmits on the talkgroup.  These talkgroups are temporary and will go away after 15 minutes if a ham operator doesn’t use it within 15 minutes.  So if you want to monitor a talkgroup that isn't static, you need to kerchunk the repeater on that talkgroup a minimum of every 15 minutes if there are no other users of that on that repeater.  (Kerchunking is OK on DMR)

    On our example below, this repeater’s Timeslot 1 has the San Diego (310670) talkgroup static, and the San Diego Hangout (310014) dynamic.  I caused the 310014 to be added to the repeater when I used it while writing this post.  Timeslot 2 has the CA (3106), Southwest (3176), SoCal (31066), and USA (31606).

    Notice how hovering the mouse cursor over a timeslot can display the name.  If the timeslot is dynamic, it also displays how much longer the talkgroup has before it expires unless it is used by someone]

    If you plan on using a particular talkgroup on a repeater, check to see if that talkgroup is static on that repeater.
      If so, make sure you use the same timeslot as shown on the configuration page.  For example, if you plan on using the CA talkgroup (3106) on this repeater, be sure to configure your radio to use Timeslot 2 when using this repeater.  
    You’ll notice that the PapaSystem repeaters all have the CA talkgroup on Timeslot 1.

  4. The final section on the left side of the page provides some antenna details about the station.

  5. Back at the top portion of the page,is the “Description” box.  This contains any additional information that the repeater operator thinks you should know.  In this case it describes who operates the repeater and that it’s available to all operators.
    1. The description section is where the operators normally instruct users on what timeslot to use when adding a dynamic talkgroup.  In this case, it’s timeslot 1. Timeslot 1 seems to be the defacto timeslot designated for “dynamic” talk groups.  In this case, I used timeslot 1 when talking to my friends on the Hangout (310014).  It stays there for 15 minutes unless I transmit again.

  6. The next section is the “Last heard” section on the repeater.  This section shows the last five sessions of traffic handled by the repeater.  This is a snapshot of the repeater’s use at a point in time.  It shows all traffic into the network where this repeater was the originator or “Source”  Let’s cover the individual columns:
    1. Time - How many minutes in the past was the entry made.  In the example, you can see that N1CLC (me) used it 11 seconds ago.

    2. Master - which Brandmeister master server handled the outbound traffic for routing into the rest of the worldwide network.

    3. My call - The callsign of the operator that transmitted into this repeater.

    4. Destination - The destination talkgroup.  You can see that I was using talkgroup 310014 and another operator was using it 52 minutes ago on for the California Talkgroup.

    5. Timeslot - What timeslot was used.  In this case you can see that I used slot 1 for 310014 which is the correct timeslot to use for dynamic groups.  Larry however should have been using TS2, because this repeater is has 3106 locked or static on TS2.

    6. RSSI - The receive signal.  I’m sitting in my home office with my HT set to 5 watts and the signal strength is pretty awesome. 

    7. Duration - This is the duration of the transmission.  The second line on this chart shows that during my first transmission, when I kerchunked the repeater, the duration is 0.  My next transmission, shown at the top, was for 3 seconds as I was announcing my test.  By looking at this column, you can tell if the repeater is really being used that much or if operators are just kerchunking the machine so that they can listen in on a talkgroup.  (It's normal to kerchunk the machine to have it subscribe to the talkgroup so that you can listen first before announcing yourself.)

    8. The button labeled “Last Heard [TG Filter] takes you to the last heard page but it is       filtered to show just the destination talkgroups that are configured on this repeater.  This auto filtering shows you if the repeater is very busy repeating traffic for the statically configured talkgroups on this repeater.  If it’s empty, the repeater may not be used all that often.

    9. The “Last Heard” button displays more rows for just this repeater, showing the last 30 transmissions made. 

  7. The last item on the page is a map showing the location of the repeater.  Look for the small green dot. 
Figure 2 (click on image for larger)

Fun Fact: The great thing about Brandmeister DMR is that the user/operator can use any talkgroup on a repeater.  Kerchunking is normal on DMR.  You’ll hear other operators kerchunk a talkgroup when they are trying to add that talkgroup to the repeater so that they can listen in and participate. 

In a future post, we’ll explore the “last heard” page to explore how it works and all of the cool things you can do to better understand what is going on and even debug your radio.

Help me improve these tip posts by leaving comments on how this format worked for you, and what you would recommend to improve these posts.



-- N1CLC, Chris Claborne
aka Christian Claborne

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