DMR to DMR w/ 2 Radios, Is this possible?

[harbinger910]

Hi, I have 2 DMR MD390 radios, but don't have a DMR repeater in my area. Can these radios talk to each other in DMR mode or do you need a repeater that supports DMR?

Tnx.

 

[tampabaynews]

Yes.

You'd program the radios with the same transmit and receive frequency (simplex).

 

[harbinger910]

Thank you! I thought so, but wasn't sure. I do have them programmed with same tx/rx simplex freq on the digital mode, but they are not communicating for some reason. I'll have to look further into it and see what's going on since it won't break squelch. Maybe I need to change something else in the programming besides just the frequencies for this work. I'm new to DMR =)

Tnx.

 

[alex5774]

Don't forget about the talkgroup, colour code, and timeslot. DMR Simplex Frequencies

 

[harbinger910]

Thanks Alex, that's probably the problem =)

 

[K5MPH]

We use DMR simplex all the time here in my area the MD-380/390 do very well on simplex try Talkgroup 99,Timeslot 1,color code 1 in both radios.......

 

[harbinger910]

Thanks guys. Where is the Talkgroup setting in the programming software?

 

[mikey60]

Create a group contact using talkgroup ID 99 and then assign that to the channel.

Note: From what I've found, the timeslot is not significant when using DMR simplex. I've tested with one radio programmed on slot 1, and another on slot 2 and they still talked to each other as long as the Frequency, Color Code, and Talkgroup ID were the same. For consistency I would suggest keeping the setting slot 1, but in the testing I did, it wasn't an issue if it wasn't the same as the other radio.

Mike

 

[jonwienke]

Thanks guys. Where is the Talkgroup setting in the programming software?

The first step is to create a Group Call Digital Contact with ID 99. Then select that Contact in the Contact name dropdown in the Channels Information dialog.

 

[jaspence]

DMR UHF simplex

The link shows the generally agreed on simplex frequencies. You should not just pick a frequency to use.
DMR Simplex Frequencies

 

[romanr]

Lastly, if you still have problems, make sure each radio has a different ID.

 

[Candy0420]

Obviously, you should connect your 2 DMR radios and create a talk group contact in your programming software. Then they can talk to each other in DMR mode.

 

[bradrnstyle]

Hi, I have 2 DMR MD390 radios, but don't have a DMR repeater in my area. Can these radios talk to each other in DMR mode or do you need a repeater that supports DMR?



Tnx.

They can. You don't need a repeater. Just make sure tx and rx frequencies are the same and talk groups are setup. Also repeater time slot does matter on simplex. They radio ignores this setting unless you're on a repeater.


Sent from my iPad using Tapatalk

 

[N4KVE]

Create a group contact using talkgroup ID 99 and then assign that to the channel.

Note: From what I've found, the timeslot is not significant when using DMR simplex. I've tested with one radio programmed on slot 1, and another on slot 2 and they still talked to each other

On the cheaper radios, this is true. But with Gen 2 Moto radios using current FW, It works properly. You can have 4 7550's, all on the same simplex freq. 2 set to TS1, & 2 set to TS2. 2 separate conversations at the same time on the same freq.

 

[mikey60]

On the cheaper radios, this is true. But with Gen 2 Moto radios using current FW, It works properly. You can have 4 7550's, all on the same simplex freq. 2 set to TS1, & 2 set to TS2. 2 separate conversations at the same time on the same freq.

Interesting. I wonder how they control TDMA Timeslot Sync without a repeater.

Mike

 

[KG4INW]

Motorola calls it Dual Capacity Direct Mode but only offers this explanation:

The Dual Capacity Direct Mode (DCDM) feature supports two simultaneous subscriber transmissions within a 12.5 kHz channel bandwidth for Direct Mode transmissions. The radios within the same group must use the same timeslot so that the group using timeslot 1 does not interfere with the group using timeslot 2. For proper operation, the radios need to identify and track the timeslot structure. A unique radio is elected as a channel timing leader. The other radios adjust their clocks to synchronize as possible with the channel timing leader.

 

[bradrnstyle]

Not to change the subject, but there is a new yahoo group dedicated to talking openly about the inter compatibility of DMR voice encryption with the TYT MD380 and the new Hytera MD782 (45/50 watt mobile rig). Could be interesting, here is the link:

http://www.groups.yahoo.com/MD782

 

[N4GIX]

Motorola calls it Dual Capacity Direct Mode but only offers this explanation:

In my understanding, the radio initiating the call takes up the task of being the channel timing leader.

 

[jonwienke]

I wonder if the "election" process is automated (whichever radio can "hear" the most other radios becomes "leader"), or if the "leader" radio must be specified manually somehow.

I see the question was answered while I was writing my post.