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BCD436HP: Simplex DMR

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KR3LC

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#1
I've searched the forum but have not found any conversation on this topic. I would like to monitor simplex DMR comms but the scanner does not seem to hear them. It's fine on conventional repeater and on trunked systems but seems to ignore simplex. Is this by design or have I missed something in setup? I have programmed in specific frequencies and relevant data plus I have direct entered but to no avail.

Thanks,
Rick


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#3
I could be wrong here, I'm an NXDN guy, not a DMR guy....

For the TDMA system to work, the radios have to be in sync to transmit in the right timeslot. This, as I recall, is handled by the repeater.
Originally the MotoTrbo radios wouldn't do DMR simplex, only analog simplex, since they didn't have the repeater there to sync the timeslots.
I ~think~ what may be happening with the simplex DMR is that the synchronization of timeslots is not something a consumer scanner can handle. Two DMR radios can handle it.
Might be a temporary short coming of the scanner firmware, or might be a bigger issue.

Again, I'm an NXDN guy, so my TDMA is a bit rusty. It's been a few years since I last played with any MotoTrbo gear, and when I did it was fresh to the market. I'm sure there are some Trbo-heads here that can correct my probable hacking of the truth.
 
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#4
Originally the MotoTrbo radios wouldn't do DMR simplex, only analog simplex, since they didn't have the repeater there to sync the timeslots.
No, because Motorola hadn't offered that feature yet. When support was added to the firmware, that feature became available.


I ~think~ what may be happening with the simplex DMR is that the synchronization of timeslots is not something a consumer scanner can handle. Two DMR radios can handle it.
Might be a temporary short coming of the scanner firmware, or might be a bigger issue.
Probably just a firmware shortcoming. With simplex (or inbound repeater traffic), there is no CACH field and an entire timeslot is missing. The voice sync pattern is also inverted. The firmware is expecting to see what it's expecting to see and simplex doesn't look like it. There is also the issue of maintaining a good symbol lock on a signal that keeps going away.

I doubt that lack of simplex support is due to any hardware limitation or licensing restriction (unless Uniden done messed up...); there *might* be an issue with the scanner's AGC response, but I doubt it.
 
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#5
Thanks for the clarification. It was about 4 years ago I messed with Trbo. Since it didn't meet our needs, I haven't touched it since.
 

KR3LC

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#6
Thanks for the replies. My local CERT uses simplex and it would be nice to have another way to listen besides the radios they issue to us active members.


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hey

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#7
Some of the guys and I from the police department just bought the BCD436HP with DMR upgrade we were wondering why it wasn't pick the school radio the last two weeks why were on patrol we like to monitor the hall monitors and security at the schools.

I hope Uniden will fix this
 

hey

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#10
gary123- We had tried that to but also still no luck. We also have the radio several feet away and it still doesn't work at all. I believe it has to do with uniden. Hopefully uniden Will fix the problem just like DSD+ did
 

rfa5

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#11
Has the DMR simplex issue been resolved or is it still a no go? I know back in the beginning of September I was trying to program some simplex frequencies and could not get it to work.
 
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#12
Not sure what "DMR simplex issue" you're referring to. Simplex in MOTOTRBO radios has worked fine for a long time. They can either be set up to use both slots (actually operating in FDMA mode) or they can be set up to use individual slots (TDMA mode, with one radio acting as a 'sync unit').

John Rayfield, Jr.

Has the DMR simplex issue been resolved or is it still a no go? I know back in the beginning of September I was trying to program some simplex frequencies and could not get it to work.
 

RRR

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#13
How do you set it up in CPS to talk in either one slot or both slots on simplex 'trbo?
 
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#14
It's called "Dual Capacity Direct Mode". It's found in the settings for each channel. It's only available in the 2nd generation of radios (XPR3000, XPR5000, and XPR7000 series).

John Rayfield, Jr.

How do you set it up in CPS to talk in either one slot or both slots on simplex 'trbo?
 

George

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#15
So, can the BCD436HP be programmed to receive DMR simplex/Direct Mode transmissions? If so, what are the steps to program a DMR simplex freq so the DCD436HP will receive it?

If the BCD436HP is unable to be programmed to receive DMR simplex/Direct Mode tranmissions, is there an updated firmware coming out to address this issue?

There are many users in my area who use DMR radios in the simplex/direct mode.

Thanks
 
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#16
There has been a new firmware released for Uniden radios this fixes the DMR Simplex issue in the new firmware if you just download it you should have a problem I've been using it for several days scanners been picking it up fine
 

George

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#17
Thanks for your response, I uploaded the 1.11.20 firmware still not receiving DMR simplex from DMR radio at work place.

My settings in my 436 for these DMR freqs are as follows:
Set Audio Type= Digital Only Search
Set Modulation= FM
Set Audio AGC= Off
Digital Waiting Time= 0 ms
Digital Threshold Mode= Auto
Digital Threshold Level= 8
Should I change any of these settings?

What exactly does the setting: "Add Current dB Channels" do?

Thanks!
 

kh6sz

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#18
Thanks for your response, I uploaded the 1.11.20 firmware still not receiving DMR simplex from DMR radio at work place.

My settings in my 436 for these DMR freqs are as follows:
Set Audio Type= Digital Only Search
Set Modulation= FM
Set Audio AGC= Off
Digital Waiting Time= 0 ms
Digital Threshold Mode= Auto
Digital Threshold Level= 8
Should I change any of these settings?

What exactly does the setting: "Add Current dB Channels" do?

Thanks!
George, change the Digital Threshold Mode to Manual. And you might want to play with the Digital Threshold level a bit, but for me, 8 seems to work the best, but YMMV!
 
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#19
Not wishing to sound pedantic, but my experience with the new 1.11.20 firmware release is that it improves sensitivity, especially on uhf, and thus DMR simplex decoding is much improved. But I dont think it's really accurate to say its fixed it as there are many examples and tests where it's still problematic. In many tests a scanner will perform pretty well vs a transceiver.....the one area scanners do seem to be consistently worse though is on DMR simplex.

George - if Manual and 8 don't work, try with a lower threshold value.
 

George

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#20
kh6sz and jhampton2000,

Thanks for the suggestions! I will continue to adjusts the settings.

Question:
When I set the Audio Type to Digital Only for the freq and press enter; I have it set for Search. Do you think if I specifically Set DMR Color Code, this might help?

Thanks again!
 
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