Why do you all enjoy using DMR?

[WRQS621]

DMR simplex is pretty cool, until you get to the edge of coverage.

 

[N2YQT]

DMR simplex is pretty cool, until you get to the edge of coverage.

QSO has now left the chat.

 

[G7RUX]

DMR simplex is pretty cool, until you get to the edge of coverage.

Well indeed, although this is much like any other transmission medium or mode. Digital modes do tend to degrade less gracefully at the edge of workable BER.

 

[bill4long]

Well indeed, although this is much like any other transmission medium or mode. Digital modes do tend to degrade less gracefully at the edge of workable BER.

We call that a "trade off"

 

[G7RUX]

We call that a "trade off"

We comms engineers call that the "digital cliff..."

 

[bill4long]

We comms engineers call that the "digital cliff..."

What comms engineers call "better qualify audio while you have it."
Hence the, ya know, trade off.
Most of the time with commercial/public-safety radio, edge conditions don't come into play.

 

[RFI-EMI-GUY]

What comms engineers call "better qualify audio while you have it."
Hence the, ya know, trade off.
Most of the time with commercial/public-safety radio, edge conditions don't come into play.

Is it really better than say, old school WB FM 16K0F3E ? The Major, begs to differ...

 

[bill4long]

Is it really better than say, old school WB FM 16K0F3E ? The Major, begs to differ...

Depends on who you ask

 

[G7RUX]

There’s the thing, it’s not “better quality audio” but is *consistent* quality audio. By the very nature of sampled audio with lossy compression the audio is degraded, albeit consistently.

 

[Echo4Thirty]

Is it really better than say, old school WB FM 16K0F3E ? The Major, begs to differ...

The major would be pleased that the DMR air interface is utilizing his FM. The carrier's frequency is shifted to TX the individual tones that makes up the encoding by the modem (FSK).

 

[RFI-EMI-GUY]

There’s the thing, it’s not “better quality audio” but is *consistent* quality audio. By the very nature of sampled audio with lossy compression the audio is degraded, albeit consistently.

consistently mediocre audio quality in my opinion.

 

[JASII]

consistently mediocre audio quality in my opinion.

What device(s) have you used to receive DMR?

 

[bill4long]

consistently mediocre audio quality in my opinion.

It's only 1/2 the bw than P25. And that BW makes a heck of a difference. I use DMR every day. But it sucks compared to P25, which is awesome.

 

[RFI-EMI-GUY]

What device(s) have you used to receive DMR?

My experience is with public safety P25 systems. I have been told by others that DMR sounds better, go figure. I have not made a comparison.

 

[G7RUX]

It's only 1/2 the bw than P25. And that BW makes a heck of a difference. I use DMR every day. But it sucks compared to P25, which is awesome.

The bitrate for a voice service on DMR is 2450 bps whereas P25 has 4400 bps, with both using the ABME+2 vocoder so it's not that surprising that P25 generally sounds better.

 

[caverjamie]

DMR sounds way better to me when everyone is using Motorola radios, but that's not surprising since they were designed to work together. I wouldn't call any DMR audio great either, but it's totally usable for conversations between brands, just not quite as nice. I have listened to P25 audio and haven't found that it sounds much better, maybe some. I don't have a lot of experience with that though.

 

[belvdr]

DMR sounds way better to me when everyone is using Motorola radios, but that's not surprising since they were designed to work together.

The radios are designed to operate on particular standards, such as DMR, P25, etc. They may have better mics and speakers, which makes them sound better, but are they designed to work better "together"? I don't work in radio, but that's my layman's take.

 

[caverjamie]

Yeah, I was referring to Motorola specific mic and speaker gain settings, optional things like companding, audio leveling, similar audio settings in cps that might work well with another Motorola but not so much with another brand.

 

[mmckenna]

Like with most digital LMR radios, there are a number of settings that can impact audio quality. It's not uncommon for someone to grab a radio, program in TX and RX frequencies, and call it done. Then the complaints about audio quality start.
A trained tech that understands all the audio settings in the radio can adjust/program as needed for the application and usually make the audio quality sound pretty good.
The difference between a good tech and some random Joe programming radios can be pretty profound.

 

[bill4long]

The bitrate for a voice service on DMR is 2450 bps whereas P25 has 4400 bps, with both using the ABME+2 vocoder so it's not that surprising that P25 generally sounds better.

Hence my "It's [DMR] only 1/2 the bw than P25"