By Toshen, KEØFHS
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After weeks of intense learning and effort, I feel like I'm just beginning to get a handle on D-STAR, having put together a nicely working solution for my shack as well as for mobile. So why am I adventuring off in a new direction already?
If you read my D-STAR story, you know that I learned a lot from a group of hams in Colorado, the Parker Radio Association (PRA). One of the things I've been enjoying doing occasionally with D-STAR is joining their digital radio net on D-STAR reflector XRF223.
During one of their nets, some of them mentioned the new SharkRF openSPOT personal access point device that they recently received, and they were really enthusiastic about it. So I ordered one to try out for myself. It should arrive any time now.
Then, during another net, they announced they were going to put up a DMR repeater on the BrandMeister Network. At first I thought, well, that's interesting, but I'm going to stay focused on D-STAR for now. However, their enthusiasm is pretty infectious, so after the net was finished, I got thinking about it and realized that this was a golden opportunity to learn something new, and also would give me a great way to try out the openSPOT device.
So I decided to dive right back into another bowl of baffling info-soup and learn how to swim all over again. I ordered a DMR HT, and as soon as it and the openSPOT arrive, I'll share my new adventure here.
2) What is DMR?
Another digital voice system that amateur radio enthusiasts can play around with.
Among the other digital voice systems being developed are D-STAR, the original (Icom and Kenwoood), System Fusion (Yaesu), and an open system that's in development, a combination of FreeDV software and an open source speech codec/vocoder, Codec 2.
DMR is a digital radio standard originally designed for commercial use and developed by the European Telecommunications Standards Institute (ETSI) beginning in 2005, which hams now are adapting for amateur radio use.
If something about using DMR for Amateur Radio doesn’t make sense, remember that DMR was created for commercial use, and was never designed nor intended for Amateur Radio use.
– Mike's DMR Doctrine, by Mike, K0NGA, of Rocky Mountain Ham Radio
And it's true, initially I did find it quite challenging to get up and running with DMR. It's different enough that I couldn't apply a lot of what I had just learned getting going with D-STAR. I also had the additional challenge of needing to figure out how to get started via a hotspot, while most info available online is from the point of view of having access to a repeater.
Finally and thankfully, some Elmers with hotspot experience helped me put it all together and get on the air.
I also met Mike, K0NGA, in person at the recent 2017 Longmont Amateur Radio Club's LARCFest, and he graciously spent some time answering some questions I had and helping clarify a few things about DMR. He's a great guy. Thanks for your help, Mike!
There's humor in them thar signals!
Laurel & Hardy lookalikes, Shoreham Airshow, 2014
Photo by Philip Bird LRPS CPAGB, Shutterstock
I found it amusing that once I finally did get things working and then spent an evening listening to hams ragchewing on various talkgroups (I'll discuss those more later, but they're sort of like conference calls or chat rooms), a lot of the chatter was hams discussing questions about DMR like, "Why does it work that way?" and "How do I make it do this thing?" So I guess I'm not alone in going through learning challenges with DMR.
In order to use DMR radios, in addition to using frequencies, channels, and repeaters/reflectors like you do with D-STAR, you also need to understand a bunch more puzzle pieces, and fit them together properly, including:
And thar's a bit of frustration, too!
Whenever I found myself growling "Why isn't this working??? ! ! !," it was helpful to keep Mike's DMR Doctrine in mind and take a step back to think about DMR in a commercial setting, like a big hospital, corporate campus, or casino. In an organization like that where there are many different departments using the radios (security, housekeeping, maintenance, catering, etc.), there typically will be a centralized IT team doing all the programming of all the locked-down radios they assign to members of the various departments. DMR makes it relatively easy for the IT team to organize communications so that the members of each team can talk amongst themselves, as well as to control whether or not they have permission to talk with or monitor other teams, all within the closed ecosystem of their organization.
Of course, that's a very different scenario than a lone ham who wants to set up a radio for his or her own use in order to connect to open repeaters put up by amateur radio clubs that allow them to be used to connect to other hams or groups of hams locally, regionally, statewide, nationwide, or worldwide. Adapting a complex system designed for the needs of a big organization within a closed ecosystem so that it can be used by hams in a more open worldwide ecosystem is a bit like trying to fit a simple square peg into a more complex hole in the shape of a 10-pointed star polygon.
And yet hams are figuring out how to make it work!
2a) Time slots
When there are so many puzzle pieces that need to be put together to set up a DMR radio successfully, it's challenging to figure out where to begin. It's a bit of a "Which comes first, the chicken or the egg?" problem, but I think a good place to start is with time slots, since they're fundamental.
If you read my Alphabetsoupese – example 2 note in the D-STAR article, you might recall that one way DMR differs from D-STAR is that it uses Time Division Multiple Access (TDMA) to generate its signal instead of the Frequency Division Multiple Access (FDMA) that D-STAR uses. Specifically, DMR uses 2-slot TDMA (the slots are numbered 1 or TS1 and 2 or TS2).
If, like me, you're more fluent in English than Alphabetsoupese, what this means is that calls on two different channels can share the same frequency simultaneoulsy. Each call is sliced up into chunks of a few milliseconds, and the slices from the two calls are interleaved on the signal. This happens so fast that we hear what we perceive of as a continuous transmission even though it's coming in chunks, looking like this:
This also means that when you program a DMR channel, you must specify both the frequency and the time slot, so that your radio and the repeater can encode and decode which chunks on the signal belong to the channel you're using.
The convention is that TS2 is used for local talkgroups and TS1 is used for non-local or wide-area talkgroups (for example, statewide, regions, nationwide, and worldwide). I know, I know, here I am talking about talkgroups again before I've explained what they are, but I had to start somewhere!
For more details about time slots, see Amateur Radio Guide to DMR (PDF), 2015, by John Burningham, W2XAB.
2b) Color codes
Another fundamental piece of the puzzle is color codes (CC). I'm not sure why they're called color codes, but they're like the Continuous Tone-Coded Squelch System (CTCSS) tones used for analog radio. When you want to use a DMR repeater, you need to program in the appropriate color code to open it up. There are 16 color codes, 0 - 15. (Strange, right? ! The color codes don't even have color names!)
Just as with analog radio CTCSS tones, you need to get the appropriate color codes from the organization operating the repeater in order to be able to use the repeater. When you program a DMR channel, in addition to the frequency and the time slot, you must specify the color code; otherwise, you won't be able to access the repeater. So the magic formula to get onto a DMR repeater successfully = frequency + color code + time slot.
Color code: 7
Time slot: 1
will get you onto the wide-area time slot of the Lee Hill repeater located in Boulder, Colorado that is linked into the RMHAM (Rocky Mountain Ham) network.
Color code: 1
Time slot: 2
will get you into onto the local time slot of the Pinery repeater located in Parker, Colorado that is linked into to BrandMeister network.
Finally … let's talk about talkgroups!
Of course, the whole point of getting onto a DMR repeater is to talk to other hams, and you do that by visiting a talkgroup, which enables one-to-many communication, sort of like a conference call or a chat room. The effect of using a talkgroup is similar to linking to a D-STAR reflector; anything transmitted to a talkgroup is transmitted to everyone listening to that talkgroup.
There are worldwide, nationwide, regional, statewide, area, and local talkgroups, as well as language-based talkgroups. For example, on the BrandMeister network, talkgroup 91 is Worldwide, 93 is North America, 3100 is Nationwide, 3108 is Colorado, 31090 is the Midwest Region (the same as callsign assignment region 0), 3171 is the Northern Colorado area, and 2 or 9 is the Local talkgroup.
In addition, there are three TAC channels, 310, 311, 312, that hams can move to for their longer chats in order not to tie up the channels that are more widely shared. For example, some hams may begin a chat on 3100, and then move to 310 to continue it.
Some talkgroups are linked across networks, for example, 3100 also is Nationwide on the DMR-MARC and DMRPlus networks, and TAC channels 310, 311, and 312 are linked across BrandMeister and DMR-MARC.
Static and dynamic talkgroups
Talkgroups are either static (always on) or dynamic (user-activated). When you activate a dynamic talkgroup on a repeater's time slot by keying up, it typically remains activated while there are transmissions on it, then drops from the repeater after some period of inactivity, for example, after 10 or 15 minutes. You don't need to manually unlink from a talkgroup. Again, the convention is to use time slot 1 to key up dynamic wide-area talkgroups, while local talkgroups typically are static on time slot 2.
Similar to how it works when you link a D-STAR repeater to another D-STAR repeater or to a D-STAR reflector, when you activate a dynamic talkgroup on a repeater's time slot, that's the only talkgroup that can be used on that time slot as long as it's active.
On some repeaters, like those on the DMR-MARC network, the talkgroups you can use on a time slot are specified by the repeater administrator, including any dynamic talkgroups, if they are even allowed. On other repeaters, like those on the BrandMeister network, users can specify any dynamic talkgroup they want to use; however, once again the convention is to key up dynamic talkgroups only on time slot 1.
Here's a section from PAPA System's BrandMeister Getting Started Guide (PDF) explaining dynamic talkgroups on the BrandMeister network:
When a user keys up on a dynamic talkgroup, the BrandMeister system creates a subscription for that talkgroup on that repeater. Then, for 15 minutes, the system will send audio for that talkgroup to the repeater. 15 minutes after the last transmission on a given repeater, that talkgroup will be dropped from the repeater.
Users have the ability to key up on any talkgroup and use it. For us here in California, a user could key up on a Florida state talkgroup and it would work fine. 15 minutes later the connection would drop. Interestingly, the timeslot is not important. The network will route the audio to the repeater and transmit on the same timeslot. It is recommended that timeslot 1 be used for wide area conversations leaving timeslot 2 available to local communications.
Unlike other linking systems there is no need to drop a connection or restore a link.
Dynamic talkgroups are time slot agnostic. This means I can key up on talkgroup 123 on timeslot 1 and could be talking with someone on talkgroup 123 on timeslot 2 [ed. note: in this example, for the person on time slot 2, talkgroup 123 likely would be a local talkgroup]. Inside the network there is no time slot, this is only considered when the talkgroup is delivered to a repeater, and it is delivered on the timeslot of the most recent transmission.
By the way: "Talkgroups" is one of those terms that doesn't seem to have a standard form of usage. I've seen TalkGroups, Talk Groups, Talk groups, Talkgroups, and talkgroups used, sometimes interchangeably in the same article. For consistency, I'm sticking with talkgroups (capitalized only at the beginning of a sentence), but am respecting how other authors use it when I reference their articles and presentations. Similarly, while most people use "time slots," some use "timeslots," again at times interchangeably in the same article. I'm sticking with time slots.
There are many sources where you can find lists of talkgroups, including:
- U.S. BrandMeister Server User Guide (PDF)
- BrandMeister talkgroups list
- DMR-MARC talkgroups
- Rocky Mountain Ham (RMHAM) Radio Network
You also can find a few lists of various talkgroups I've been exploring at the end of this article in the 7) A few notes section.
Zones are an organizational tool, like file folders, for your channels; in other words, a zone is a group of channels.
The channel selector on many DMR radios let's you choose from 16 channels. In order to get past that limitation, you can use zones. For example, I have a DMR radio that can handle 64 zones. If I fill all of them with 16 channels each, that gives me a total capacity of 1,024 channels.
You can organize your zones however you want, for example, you might want one or more "Home" zones for channels that correspond to your favorite talkgroups that you can reach via the repeaters that are within range of your home. You might want a "Commute" zone that corresponds to the talkgroups you most often use via the repeaters that are in range as you drive to and from work. If you use a hotspot, you might want some "Hotspot" zones for the talkgroups you key up via your hotspot. You might want some other zones that correspond to the groups of talkgroups your club uses, or to nets you frequently participate in. Some people set up zones based on repeater locations.
It's pretty easy to use zones: you create a zone, name it, and then add channels to it (up to 16 for a radio that supports 16 channels per zone). Optionally, you can change the order of the channels within the zone.
2e) RX group lists
When you program your channels, you optionally can choose to monitor more than just the talkgroup associated with that current channel.
For example, if you're on a repeater that has multiple talkgroups that share a time slot and your channel is for one of those talkgroups, you might want to monitor all of the talkgroups that share that time slot to hear whether there is ongoing activity on any of the other talkgoups. This can be very helpful to ensure that you don't disrupt a call that is ongoing on a talkgroup that is on the same time slot as the one programmed into your current channel.
Another example is that you might want to create an Rx group list for a group of your favorite talkgroups, so you can monitor whatever activity is going on in them. However, it might be better to use the scan feature for this instead.
Even if you have set up an RX group list with multiple contacts, when you transmit, it goes only to the TX contact set up for the channel you're on. If you hear someone on a talkgroup that is different from the one you have programmed for the channel you're currently tuned to, you can quickly tune to the channel programmed for that other talkgroup in order to join that conversation/
However, in many cases, you might want to monitor only the channel you're on, in order to avoid any confusion.
Note: Some radios have an optional feature that, when enabled, will switch to the channel of the last talkgroup that was received as long as you PTT shortly after that last received transmission ended. This feature is both good and bad. On the good side, it enables you to reply to a received transmission without having to manually change channels. On the bad side, you might find that you've accidentally been transmitting to a talkgroup other than the one you intended to.
2f) Scan groups
You can monitor multiple channels by creating scan groups. For example, you might want to monitor all the channels in a region, all the analog channels in a frequency range, or a group of your friends.
A scan group can combine digital and analog channels, and can include channels from multiple zones, time slots, and color codes. If your radio has limits on the number of channels per zone, that limitation doesn't apply to the number of channels you can have in a scan group.
One thing to keep in mind is that scanning takes a lot of power, so will drain your battery faster than regular use; although in general, DMR radios are more power efficient than other Digital Voice radios because of the way the bandwidth usage is optimized with two simultaneous channels.
2g) DMR networks
This is one area where DMR seems to be quite different from D-STAR. Just as in the D-STAR playground, some DMR repeaters are standalone and used for local communication only. DMR and D-STAR diverge in how they handle it when repeaters are interconnected.
In D-STAR, repeaters can be linked to reflectors, for example, there are a bunch of D-STAR repeaters here in Colorado that are permanently linked to a single statewide reflector, and then whatever is transmitted on one of those linked repeaters is reflected to all the other linked repeaters. It's also possible for a ham to temporarily link an individual repeater to another repeater or reflector for a call.
In DMR, repeaters using static talkgroups are linked together in network configurations that are decided by the system administrations, which can't be changed by individual hams. Some repeaters also allow hams to temporarily subscribe to specified dynamic talkgroups.
Initially, there were two main worldwide umbrella networks for amateur radio, DMR-MARC (the largest), built on MotoTRBO products, and DMRPlus, built on Hytera products. It's my understanding that the two networks didn't interconnect initially, but more recently, the two teams have been collaborating on building interconnectivity.
More recently, a new worldwide network has launched, BrandMeister. In a little over a year (as on Jan 2016), it apparently has grown to be the largest amateur radio DMR network in the world. As per the section I previously quoted from the PAPA System's BrandMeister Getting Started Guide (PDF) BrandMeister users can key up to (a.k.a., temporarily subscribe to) and use any talkgroup.
There also are other, typically regional, networks, for example, Rocky Mountain Ham Radio operates its own RMHAM network that covers Colorado and parts of New Mexico and Wyoming. RMHAM repeaters up and down a large swath of the Rocky Mountain region are linked together making it possible for a large community of hams to communicate on the supported talkgroups.
The BrandMeister network
On the BrandMeister wiki, they say:
If you are an amateur radio operator working in digital voice modes like D-Star, DMR, C4FM, APCO25 or others (not all are supported yet!), you do not need to know much about BrandMeister, and it's very easy to operate on its infrastructure.
However, I'm the kind of person who doesn't like black boxes, so I wanted to learn a little bit more about BrandMeister as part of getting up and running on DMR. Here's what I've learned so far. First, "BrandMeister" is a play (in German) on the words "brand new master server."
It's a decentralized, worldwide, community-driven network being developed by an international team: Artem, R3ABM, Moscow, Russia; Rudy, PD0ZRY, Ultrect, The Nederlands; Yentel, West-Flanders, Belgium; Jonathan, EA1HET, Spain, Wijnand, PD0MZ, The Nederlands; Denis, DL3OCK, Berlin, Germany; and Adam, SQ7LRX, Poland. They are joined by teams in countries worldwide that are bringing master servers online, as well as by other teams putting repeaters online. As of Nov 2016, there were more than 30 BrandMeister DMR Servers deployed, connecting hundreds of repeaters in more than 40 countries.
As of early 2017, BrandMeister is just a bit more than a year old: development work began in 2014, and the first master servers went online in November of 2015. It's spreading as fast as a wildfire, which I guess is appropriate since, in German, "Brandmeister" (little "m") means fire chief.
From their wiki:
BrandMeister is an operating software for master servers participating in a worldwide infrastructure network of amateur radio digital voice systems.… BrandMeister allows you to connect to MOTOROLA DMR-MARC and Hytera DMRplus networks, this means you can operate with other DMR amateur radio operators on both infrastructures the same time.
BrandMeister has a really nice, robust User Dashboard that includes activity meters, a real-time Last Heard page, and a fun feature called the Hose Line, which enables you to listen in on transmissions around the world, including drilling down to specific talkgroups.
The dashboard also earns my respect for its clean, modern, and fully responsive design, which scales nicely to any size device. It's nice to see an amateur radio-related website that looks like it was coded in this century.
3a) Choosing a radio
The operative word for me when choosing my first DMR radio was "inexpensive." Since I wasn't clear what I was getting into with DMR, and I already have a nice D-STAR radio for all-around, multi-mode use, I decided to just barely stick my toe in the DMR soup to begin with. So to get started and on the air with DMR, I chose the CS580, made by Fujian Beifeng Telecom Technology Co. (BFDX), and distributed in the U.S. by Connect Systems (CSI), a company that also designs its own radios for the commercial and amateur radio sectors.
The CS580 is a compact radio that feels solid and well made, and there is a decent, free Customer Programming Software (CPS) package available that enables programming the radio. The CPS is a bit clunky to use, but it works well enough to get the job done.
There's an interesting conundrum here. It would be great to get a TRBO radio to use on DMR, but they definitely are aimed at the commercial market. The radios themselves are pricey, but I'm sure they are top tier and worth the cost. The thing that makes them a really costly proposition for an individual ham to use is the CPS, which costs a couple hundred bucks on top of the radio itself, and that gets you only a subscription license good for just a few years of use.
3b) Choosing a hotspot
I already had decided to give the SharkRF openSPOT a try, and had ordered it before I made the decision to try DMR. I then realized that it will provide a good starting point for DMR: I can learn about both DMR and the openSPOT in one go.
SharkRF describes the openSPOT as "a standalone digital radio IP gateway / hotspot." My plan is to use the openSPOT as my DMR base station.
The openSPOT is easy to use, and the SharkRF team has created excellent documentation, so I won't be writing much about how to set it up, other than a few hints here and there.
By the way, like BrandMeister, the SharkRF team—Ákos, HG1MA, and Norbert, HA2NON—launched a clean, modern, and fully responsive website, which scales nicely to any size device. Bravo!
For my mobile DMR solution, I plan to use my BlueStack+DVMEGA combo running the BlueDV app on my Android phone, since that setup supports DMR as well as D-STAR. For more info about my mobile setup, see 5b) Just can't wait to get on the road again! in my D-STAR article.
My own choices aside, there are other personal access point devices that support DMR. See the Personal access point hardware section in my D-STAR article to read about other devices that are available.
4) Putting it all together
a) First things first: Register for CCS7 ID
b) Customer Programming Software (CPS)
c) Read radio to start a new codeplug
d) General settings
e) Create contacts
f) Create RX group lists
g) Create digital channels
h) Create scan lists
i) Create analog channels
j) Create zones
k) Save codeplug and write to radio
4a) First things first: Register for CCS7 ID
To operate on the DMR system, you need to register with an authentication and routing system called CCS7 (Callsign Communication System, 7-digit).
The DMR system uses the CCS7 ID number instead of your callsign, though its authentication service maps your CCS7 ID number to your callsign.
You can register using the DMR User / Repeater Registration form. Choose the individual registration, which is also for private hotspots and repeaters, and then select the DMR radio option.
This is administered by volunteers, so be patient; it can take a day or a few days to receive your CCS7 ID.
Note: If you already have a CCS7 ID—for example, I got one to use with D-STAR on DCS reflectors—that also will work for the DMR system.
Note 2: Since DMR operates using the CCS7 ID, your callsign isn't transmitted to the radio the way it is with D-STAR, so you need to announce your callsign just like you do on analog.
4b) Customer Programming Software (CPS)
Many ham radios can be programmed from the keypad on the radio, but the process is cumbersome. In many cases, the manufacturer or a third party offer radio programming software to make it easier to program a radio, especially when you want to add a lot of memory channels.
DMR radios are different because typically they allow programming the radio only from an application called Customer Programming Software (CPS). In fact, because of this, commercial DMR radios often don't have keypads; although some DMR radios made for amateur radio now do allow some limited amount of programming to be done via a radio's keypad.
Using the CPS, you add your basic settings and defaults, like your CCS7 ID and, in some cases, how you want certain buttons to behave (for example, do one thing when you short press them and another when you long press them). You also add your contacts, RX group lists. zones, and scan lists, and then weave them all together as channels.
4c) "Read" your radio to start a new codeplug
I'm a fairly cautious person, so the way I started out was to open the CPS and "read" my new radio, save that as a codeplug backup file, and then make a copy of it to work in. That way I'll have the radio's original codeplug to go back to in case, for example, I mess things up badly enough that I want to start over, or if I want to reset the radio to give it to someone else.
Most DMR radios I've seen require a special cable that enables them to be connected to the PC's USB port. Once it's plugged in, open the CPS, turn on the radio, and then click the CPS Read button. It takes just a few moments to read the radio's data.
Similarly, whenever you want to update your codeplug, make a copy of it, and then make your changes to the copy. That way, you can always revert to the previous working codeplug, if you need to.
4d) General settings
There are a variety of general settings. The most important one is to enter your CCS7/DMR ID as the device or radio ID.
Other settings control things like how buttons behave, how menus are displayed, and whether and how one-touch calls are set up.
4e) Create contacts
There are a couple kinds of contacts: talkgroups and individuals. For each:
- Contact name/alias: A description of the talkgroup (for example, Colorado statewide) or individual (callsign and first name).
- Call type: Group call, Private call, or All call. Private calls are rare for ham radio; an example when it is used is a parrot call (echo test). An All call, which is more of a commercial feature used by a user in a supervisory capacity, is a call from an individual radio to all radios in the system.
- Call ID: A talkgroup ID number or an individual's CCS7 ID.
- There may be other options, for example, whether or not a receive tone sounds prior to unmuting the radio when a Group, Private, or All call is being received.
4f) Create RX group lists
I'm still learning about RX group lists, and there's conflicting information.
One thing I've heard is that you need an RX group list for every contact you're going to create a channel for, and the list must at least contain that same TX contact (and optionally, you can add more contacts to the RX group).
However, I've also read that, at least for the CS580 radio, you don't need to create an RX group list if all you need for the channel you're creating is to receive the TX contact. Another example: the Hytera AR865 supports only 32 RX group lists, so obviously that can't need an RX group list to match each TX contact. So this appears to vary from radio to radio.
The DMR Programming for Amateur Radio by Mike, K0NGA, Rocky Mountain Ham Radio, contains a good explanation of how the RMHAM network prefers hams using their network to set up their RX group lists.
For my own codeplug, I set up just a few RX group lists to use with channels that I set for local repeaters that have multiple talkgroups sharing a single time slot.
4g) Create digital channels
This is where it all comes together.
i) Primary channel settings
The following essential items that must be set up for each channel:
- Channel name
- Color code. Hotspots typically use color code 1.
- Time slot. Hotspots typically use time slot 2.
- RX frequency. When setting up a hotspot, you choose a frequency to use with it, which should be one that is mostly unused in your area. Then you use that frequency for every channel that uses the hotspot.
- TX frequency. In some CPS applications, this can be auto-generated from the offset. Hotspots are simplex.
- TX contact
- RX group list
- Power level (default). On my radio, the choice is Low (1 watt) or High (4 watts). I chose Low for all the hotspot channels I set up.
- Admit criteria. This controls when your radio is allowed to transmit on a DMR repeater. The most common recommendation I heard was to use color code free, which means that you're allowed to transmit on the repeater when no one else is. That way, you avoid doubling. This is one advantage of the DMR standard: your radio is constantly receiving from the repeater in between your micro transmissions, so it knows the status of the repeater at all times.
ii) Other channel settings
In addition, there are a few other items that can be set up for each channel, including:
- Talkaround (on/off). This typically means using the RX frequency (a repeater's output channel) for direct simplex communication, radio to radio, rather than through the repeater. For example, talkaround can be useful if someone with a more powerful radio that can hit the repeater wants to talk to someone nearby with a less powerful radio that can't hit the repeater.
- TX Timeout Timer (TOT). A limit on how long you can transmit (in other words, the length of time that you can hold down PTT). This is done to protect the radio. A reasonable timeout is 120 - 180 seconds (in any case, it should be set to an amount of time less than the repeater's timeout). There's also a TOT pre-alert tone that you can set to warn you a few seconds before the timeout, so you can transmit "Pause," and then reset.
- Scan list. This is a "Which comes first, the chicken or the egg?" step. You have to create channels first in order to create scan lists (see the next step), but then after you create the scan lists, you have to come back and add them to the channels you want to have them available for.
4h) Create scan lists
This is another area where I'm still learning. So far, I've set up just a few scan lists, for example, one that includes US Wide and Tac 310/311/312, another that includes all the BrandMeister regional talkgroups, and a third that includes all the talkgroups on nearby DMR repeaters.
I created a channel in each of the associated zones that has an appropriate scan list selected for it, so I can dial in that channel and then begin scanning.
4i) Create analog channels
Setting up an analog channel for a DMR radio is similar to what you do for an analog radio. There is one difference in the CPS I use: I need to set the CTCSS tone for both the RX and TX frequencies, even when they are the same.
4j) Create zones
When I created my zones, I thought about the groups of channels I think I'll want to use in proximity.
Since most of my activity will be via the openSPOT, and since that hotspot has separate connectors for the BrandMeister and DMR-MARC networks¹, I set up my zones this way:
- The BrandMeister talkgroups I'll monitor most frequently via hotspot.
- The UHF analog frequencies I use.
- The DMR-MARC talkgroups I'll monitor most frequently via hotspot.
- Talkgroups on the nearby DMR repeaters I'll monitor when driving.
- All the BrandMeister regional talkgroups via hotspot.
- All the BrandMeister U.S. statewide talkgroups via hotspot (obviously, this requires multiple 16-channel zones).
Then I added the appropriate channels to each zone, and organized the channels in the order I figure I'll flip through them.
 As of firmware version srf-osp-1.1-0101.bin dated 2017-02-19, openSPOT appears to now use a single connector for both the BrandMeister and DMR-MARC networks.
4k) Save codeplug and write to radio
As you're working in the CPS, you should save regularly, and again when you're finished.
The final step is to connect your radio to your PC with the programming cable, turn on the radio, and then click the CPS Write button to transfer the codeplug to the radio. It takes just a few seconds. My radio restarts when the write is complete. At that point, all the new contacts, zones, channels, basic settings, etc. are in the radio and ready to use.
And it worked. I fired up my openSPOT, set the connector to Homebrew, turned on my radio, selected a channel with a BrandMeister talkgroup, announced myself (DMR ettiquette is to give your callsign and announce which talkgroup you're monitoring, for example, "KE0FHS monitoring 3108"). And then I had my first DMR chat. What a thrill !
⇄ Give me a holler!
ke0fhs at toshen.com