Advice needed with listening to DMR

[rootbeerefloat]

Hello! I am fairly new to the world of radios. I have used an analog radio for a little while, and I feel comfortable with it. Recently, I decided to get into digital radio, so I purchased a Baofeng DM-5R. I have realized that listening to digital radio is much trickier than analog radio. I live in the Bentonville, Arkansas area, so any systems I reference can be found here. My understanding is that to setup a DMR to transmit and receive signals, you need a) the frequency, b) the repeater slot, and c) the talkgroup. I have a few questions surrounding these things, specifically the repeater slot, and the talkgroup, as well as some other general questions:

1) Do you need to know all three of these things just to listen (and not to transmit) to a DMR system? I’ve had people tell me that a talkgroup is only necessary to transmit. Is there a way to simultaneously listen to all talkgroups on a system?

2) Which repeater slot should I set for a system that does not use a repeater?

3) If I only know the frequency of a system, is there a way to find the other required pieces of information? For example, on the radio reference site linked above, the Centerton Police Department and its frequency are listed. It doesn’t say analog or digital, but I believe that it is digital. Is there a way to find the talkgroups used on this system?

4) Finally, I’ve read a bit about trunked radio systems. Is it possible to listen to a trunked system with this radio?

Any help on the subject would be greatly appreciated! Thanks!

 

[chief21]

1) Add Color Code to the list of necessary DMR settings. Some radios can operate in "Digital Monitor" or "Promiscuous" mode, which ignores certain of these settings (not all operate the same way). To my knowledge, the Baofeng does not offer this capability.
2) In DMR, most direct (non-repeater) transmissions do not use Time Slots.
3) According to the listing, Centerton Police are conventional UHF... not digital. Of course, this may have changed.
4) The Baofeng cannot follow trunked radio conversations.

Be aware that there are other digital modes besides DMR. In most areas, the most common digital mode for public safety systems is P25. If your primary interest is listening to public safety, your needs would probably be best met with a true multi-band scanner. Depending on the brand and model, this would allow you to track trunked systems and certain types of digital signals on multiple frequency bands.

 

[Ubbe]

DMR are always using time slots but in simplex without a repeater it only uses one slot but as a simplex slot are not numbered it doesn't matter which one you use but the radio has to be set to simplex mode, usually by setting the TX and RX frequency exactly the same.
It usually works fine to listen to trunked systems if you scan all its voice frequencies and slots. If you have two voice frequencies you have to program 4 channels with each frequencies slot as a seperate channel.

You have to know the color code and the talk group numbers to be able to listen.

If you cannot find any info about the system and you are certain that it is using DMR you need to use a radio that can decode the info for you or use a $10 SDR dongle and the DSD+ program on a computer.

/Ubbe