TYT MD-390 DMR Issues

[mfn002]

I recently acquired a brand new TYT MD-390 to monitor local TRBO channels (both my 436 and 536HP are tied up monitoring trunked systems and buying another x36HP is out of the question). However, I quickly encountered issues with receiving the channels. Despite having the correct slot and color code, the radio won't decode the signal. It'll show that it is receiving, with the RSSI at max and the green RX light illuminated, but there is no audio. I also tried an MD-380 but had the same result. I do have the DMR upgrade installed on both the 436 and 536, and they received the channels fine.

 

[Forts]

Conventional DMR? Perhaps RAS is in use...Scanners will ignore that but the radio won't. You would likely need to use DSD+ to confirm.

 

[mfn002]

What's RAS?

 

[Forts]

It's a Motorola repeater security feature... Restricted Access to System. Basically it's a key that is entered into the repeater and radios. If the key doesn't match, or isn't there, the radio can't transmit or unmute to any audio.

The actual voice packets aren't altered in any way, just the headers that identify them... which scanners ignore, so they still work on RAS systems (at least Uniden ones do, I'm not sure about Whistler).

 

[mfn002]

It's a Motorola repeater security feature... Restricted Access to System. Basically it's a key that is entered into the repeater and radios. If the key doesn't match, or isn't there, the radio can't transmit or unmute to any audio.

The actual voice packets aren't altered in any way, just the headers that identify them... which scanners ignore, so they still work on RAS systems (at least Uniden ones do, I'm not sure about Whistler).

Ah, okay. I guess I'll have to settle with getting another 536, then.

 

[Forts]

If that's indeed what it is.... As I mentioned you'd need to check with DSD+.

 

[Forts]

Just curious... you do have the proper group code assigned to the channels in the 380/390, correct?

 

[ScanWI]

RAS only restricts Motorola Radios with newer firmware from receiving the channels. I have a MD-380, CS700, and others that decode RAS just fine.

I would make sure you have the proper group codes assigned to the channel.

 

[mfn002]

What group code? I didn't see an option for one on the MD380 software. I'm also pretty new to the whole DMR thing.

 

[Forts]

Really.... RAS should block any 'commercial' DMR radio, not just newer Motorolas. Hytera etc will not pass audio with RAS. I've also heard from multiple people that the MD-380 will NOT work with RAS. Unfortunately (?) I don't have any RAS enabled systems in my area to test my collection against.

 

[Forts]

What group code? I'm pretty new to DMR.

That would likely be your problem them

For receiving DMR in a 'real' radio you need 4 components:

- frequency
- color code
- time slot
- group code (talkgroup essentially)

The group code has to be assigned to the channel you are trying to program otherwise it won't decode a thing. Scanners will work on the wildcard principal where they will decode all traffic on the channel.

If you are using the 380/390 for RX purposes only then you need to put the group code into an RX Group List and assign it to the channel. Feel free to PM me if you need a little more guidance.

 

[mfn002]

Thanks. How would I go about determining what this group code is?

 

[Forts]

Your scanner should show you during a transmission.

 

[mfn002]

When my scanner keys up, the only thing besides the color code that shows is "S2". In case I haven't mentioned it, these are conventional channels and NOT trunked.

In case anyone's wondering, here is one of the channels I'm trying to pick up:
http://www.radioreference.com/apps/db/?fccCallsign=KNHA717

 

[Forts]

Can't help you with that part, I'm only familiar with Whistler DMR scanners. Is the talkgroup listed in the database?

 

[mfn002]

No. It's listed in the database as being analog. The channel just went active again, and it doesn't show a TG. Just the slot and color code.


Sent from my iPhone using Tapatalk

 

[ScanWI]

If the Channel is listed as analog then you will need to listen to it in analog mode, if the channel is a DMR channel you will need three things to listen to the traffic, Time Slot, Color Code, and Group. The group can be found with DSD or with a DMR capable scanner.

 

[mfn002]

If the Channel is listed as analog then you will need to listen to it in analog mode, if the channel is a DMR channel you will need three things to listen to the traffic, Time Slot, Color Code, and Group. The group can be found with DSD or with a DMR capable scanner.

What I'm saying is that the DB lists the frequency as an analog channel (and thus no group) but what I found when listening to it is that it is actually digital. I have been listening to it with both my 436 and 536, which both have the DMR upgrade installed. For some reason, both of them don't show a group number, just color code and slot.

I would use DSD, but Norton won't let me install it. It simply treats it as being "unsafe" and deletes it.

 

[IAmSixNine]

Put your scanner in search mode then hold on the frequency.
From there any time its active it should show you the necessary information.

 

[mfn002]

Did that. On at least three different DMR channels, all I've gotten are the slot number and color code. No TG. Oddly, I've noticed that the slot number seems to change from one transmission to the next. For example, during one transmission it'll show "S1", but on the next "S2", or sometimes it'll stay on one or the other.