Comparison between digital voice and analog FM

Here is a video with a comparison between high fidelity digital voice and NBFM: https://www.youtube.com/watch?v=lyJOjp7N5r8

FM is scratchy but good to copy below 40 dBm, but digital is better on the ear until about 40 dBm after which it drops sharply. In a related video, the Codec2 mode can be decoded well below the minimum level for NBFM.

I like digital voice. I enjoy no interference and trash. Yes you get R2D2. Yes when it drops it drops but it works well in an Urban or Suburban environment.

When in a rural area definitely all about analog. Rougher terrain, fewer people. Analog will be a better choice.

The sad thing inwith so many digital modes it fragments people and gives the idea no one is on. With the MMDVM and similar interop devices though I hope the trend is an interop repeater and anyone uses any mode from their home, mobile or ht.


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I find analog voice through a repeater much better than any digital. Digital voice sounds nasally, volume varies dramatically. When listening to DMR there seems to be a lot of signal variation with some squawks and squeaks that are 10 db above voice and extremely annoying. This is particularly annoying for people with hearing aids. I am still trying to find where digital has less interference and trash, as when using an analog repeater that has not been an issue to me. At least with analog and dropping of signal, one can generally make out words to know what is trying to be said. But digital is useless on fringe. I cannot comment on simplex as have not used digital in that environment. But I can see Digital having less white noise in this environment.

robertmac said:

I find analog voice through a repeater much better than any digital. Digital voice sounds nasally, volume varies dramatically.

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This is often due to poor setup of the radios.
Many years ago I was in the market for a new trunked system to replace an aging/failing SmartNet system.
Tried MotoTrbo, and it sounded like crap. This was from a Motorola sanctioned shop, one of the bigger ones in the state.
Tried an NXDN repeater running side by side. Night and day difference.

The problem with digital is that there are a lot of variables involved. Manufacturers can compensate for most of it, but it requires some knowledge when setting up the radios.

When I was turning up our NXDN trunked system, it took a lot of trial and error to get it to sound good. Even then, I turned to Kenwood for assistance in setting up the radios.

robertmac said:

When listening to DMR there seems to be a lot of signal variation with some squawks and squeaks that are 10 db above voice and extremely annoying. This is particularly annoying for people with hearing aids. I am still trying to find where digital has less interference and trash, as when using an analog repeater that has not been an issue to me. At least with analog and dropping of signal, one can generally make out words to know what is trying to be said. But digital is useless on fringe. I cannot comment on simplex as have not used digital in that environment. But I can see Digital having less white noise in this environment.

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I agree. I still prefer analog.

However, I have had the opportunity to do a side by side test, with most variables controlled:

I've got two VHF analog systems, repeated, 12.5KHz FM. Quantar and MTR2000 repeaters, wireline control from dispatch, Zetron 4048 consoles. Link between console and repeaters is mostly fiber optic, with the last stretch being twisted pair, known good cable.
Kenwood NexEdge trunked system. 12.5KHz digital channels, NXR900 repeater with Crescend amps. Radio link from dispatch.

Same dispatcher, same console, same mic.

On my end:
Kenwood NX-700 VHF mobile, 12.5KHz FM analog.
Kenwood NX-900 800MHz mobile, 12.5KHz NexEdge.
Same speakers, same vehicle.

Dispatcher sounds good on the VHF analog systems.
Seconds later, hear her talking to me on the 800MHz digital system, and it sounds better. More dynamic range, cleaner audio.
Side by side, same radios, speakers,dispatcher, etc. and the NXDN sounds better, at least in my opinion.

I've also got a clear shot running about 80 miles south down the highway, clear line of sight from our repeaters all the way.
VHF analog slowly deteriorates towards the fringe, but the 800MHz digital stays the same.

Until you hit the wall, then they both drop.
Beyond the 80 miles, I'll occasionally get a spot of coverage from VHF, but 800MHz is gone.

But, I do agree, I'd still take the analog if I had the choice.
And, as I said, so much of it involves having the radios set up properly. Unfortunately I think most radio shops don't put much effort into it.

Some amateur networks request that AGC be turned off which often leads to varying audio levels as everyone talks differently and then the operators never bother to fine tune their mic gain to their speech patterns.

I've actually found many modern digital radios have better receive sensitivity when operating in digital compared to analog. A great early example would be my Motorola XPR6550...which spec'd out 12 dB SINAD @ -118.4 dBm and 5% BER @ -121.3 dBm. I'll add, at 20.8% BER you hit the maximum theoretical error a DMR radio can handle (according to the Shannon-Hartley theorem). That 2.9 dB difference is enough to allow around a 39% increase in coverage (I've seen 34% in real world testing).

Keeping firmware up-to-date also plays a big part in how well digital works. I prefer digital as I find it easier to listen to bit error compared to noise. I can't hear specific (such as human voice) when there is background noise involved (hearing damage). Noisy environments are slightly hit and miss. Not but two weeks ago my father was on a side-by-side and started talking to me using an Astro Saber (with a mid-production firmware release) while the engine was running. My father in-law remarked how clear and noise free it came out across my XTL5000 (most recent firmware). It just varies with the user.

robertmac said:

I find analog voice through a repeater much better than any digital. Digital voice sounds nasally, volume varies dramatically. When listening to DMR there seems to be a lot of signal variation with some squawks and squeaks that are 10 db above voice and extremely annoying. This is particularly annoying for people with hearing aids. I am still trying to find where digital has less interference and trash, as when using an analog repeater that has not been an issue to me. At least with analog and dropping of signal, one can generally make out words to know what is trying to be said. But digital is useless on fringe. I cannot comment on simplex as have not used digital in that environment. But I can see Digital having less white noise in this environment.

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There is no comparison between the DMR-MARC DMR network and a properly setup and configured LMR DMR system.

There is a night and day difference in audio quality between the two.

DMR is much easier to listen to than analogue.
AGC makes a HUGE difference. You don't have the huge differences in audio levels.

NXDN has much better audio quality than DMR in my experience. Although my MXDN use age has only been on simplex.

Having used a legacy VHF analogue system made up of Vertex repeaters and Vertex portables compared to DMR system that replaced it... DMR all the way. No static, no audio all over the place. Active noise cancelling speaker Mics make a HUGE difference.

As for the fringe. The fringe, in my experience with DMR in LMR, is MUCH farther out than analogue. I have had 100% audio recovery on DMR at signal strengths that would render analogue useless. Seeing nothing more than the green busy light on a XPR6550 with out the antenna symbol or any RSSI bars showing and getting full audio recovery with out any artifacts is impressive.

There will always be a need for analogue LMR. The oilfield/resource road radio use, for example, is a good place for analogue comms. All radios do analogue, and you are not limited to one manufacturer. Going DMR, NXDN or P25 for simplex VHF comms does not make sense. Good old analogue works just fine.


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640K is enough for anybody.

jonwienke said:

640K is enough for anybody.

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OMG Bill Gates!

Another comparison between digital and FM analog: https://www.youtube.com/watch?v=h5KpDevGfB8
This time FM is narrow band (2.5 KHz) and digital uses Codec2. Digital voice stays readable well below the point where analog disappears. The 7-8 dB difference is equivalent to multiplying your radio power 5-6 times. Codec 2 performance is almost equivalent to SSB.

kayn1n32008 said:

All radios do analogue, and you are not limited to one manufacturer. Going DMR, NXDN or P25 for simplex VHF comms does not make sense. Good old analogue works just fine.

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There is the major thing, for me, to stick with FM. Which digital format? If you have NXDN radio, and end up in an area where everyone is using D-Star, you are stuck without communications.

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I own radios that operate in multiple modes. D-Star, DMR AND NXDN. I research the areas that I am traveling to before I go to see what modes are in use, and bring the radio that will be the most useful for me.


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krokus said:

There is the major thing, for me, to stick with FM. Which digital format? If you have NXDN radio, and end up in an area where everyone is using D-Star, you are stuck without communications.

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The same is true if you try to use a FM radio on a digital repeater.

I actually saw a Facebook post last night concerning poor audio quality with Yaesu's System Fusion (but it quickly grew to various audio qualities on all FM digital modes). Like everything on Facebook, everyone had an opinion. Some assumptions were made by some, which were rather incorrect, and some plausible assumptions were made by others.

To sum things up.

• 
  C4FM is a rather poor marketing term on Yaesu's part as C4FM is the modulation scheme used by YSF, NXDN and P25.

• 
  DSP development varies. Many commercial solutions have user upgradable DSP firmwares. Some users did note that P25 had cleaner audio in many cases compared to YSF but P25 DSP has over 20 years of development (by multiple manufacturers) compared YSF.

• 
  Some users did prefer the lack of having to strain against background noise listening to weaker analog signals versus the obvious bit error in reproduced speech in digital operation.
  

kayn1n32008 said:

I own radios that operate in multiple modes. D-Star, DMR AND NXDN. I research the areas that I am traveling to before I go to see what modes are in use, and bring the radio that will be the most useful for me

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So buy a handheld with all that enabled, which is going to be around $700 to $800, instead of one quality 2m for $150, or nice dual-band for $300.

Where is the benefit?

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jonwienke said:

The same is true if you try to use a FM radio on a digital repeater.

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True, but the whole idea is to have FM there, instead of any digital format.

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That may be your idea, but isn't necessarily anyone else's. If FM repearers are what's available, then use FM. But if all that is available is DMR or NXDN, then bringing an FM radio isn't going to give you compatibility, any more than bringing a D-Star radio would.

What a completely misleading video! It has so little to do with what we actually hear. It's a product intended to offer an alternative to echo link, and has a number of different codecs available. It just allows streaming on a narrow band comms link.

It's (at least as far as I can tell) using a FM link used to carry data with a lowish bandwidth, so missing out on many of the benefits of proper digital comms that doesn't use F1E or maybe F2E. Proper digital using FSK is quite different.

The differences from a purely listener perspective are simply the realism the vocoder design can manage. Different brands do it with more or less success than others. Some sound quite human but a little rough sounding while others are easier to listen to, but more robotic and electronic sounding. Some make recognition of individual voices difficult while others manage the subtleties so you can hear accents, or tricky pronunciation. NXDN, MTRBO and most of the DMR radios now do it pretty well. That video just confuses, as it's not really applicable to what we're talking about in general.

krokus said:

There is the major thing, for me, to stick with FM. Which digital format? If you have NXDN radio, and end up in an area where everyone is using D-Star, you are stuck without communications.

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Last time I checked my NXDN, DMR and D-Star radios all do wideband analogue, so no, I'm not stuck with out communications. The Labour Day weekend is a good example of this. I took both my NXDN mobile and my NXDN portable. I came across a single vehicle accident, in an area of no cell service. While my call for assistance on the local linked analogue repeater system was not the first to have EMS and police dispatched, it was the first to confirm that they were on their way. I did this with my NXDN portable. so no, I was not with out comms. side note, Global Star does not work well in narrow east-west valleys when in northern Canada... darn polar orbits...

MCore25 said:

I actually saw a Facebook post last night concerning poor audio quality with Yaesu's System Fusion (but it quickly grew to various audio qualities on all FM digital modes). Like everything on Facebook, everyone had an opinion. Some assumptions were made by some, which were rather incorrect, and some plausible assumptions were made by others.

To sum things up.


C4FM is a rather poor marketing term on Yaesu's part as C4FM is the modulation scheme used by YSF, NXDN and P25.

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Agreed, Yaseu made a mess of their marketing of YSF,

krokus said:

So buy a handheld with all that enabled, which is going to be around $700 to $800, instead of one quality 2m for $150, or nice dual-band for $300.

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I own a 'nice dual band radio', I also own a nice DMR radio, and a nice D-Star radio.

Tell me what radio I can buy that does DMR, D-Star and NXDN? SMDH...

jonwienke said:

That may be your idea, but isn't necessarily anyone else's. If FM repeaters are what's available, then use FM. But if all that is available is DMR or NXDN, then bringing an FM radio isn't going to give you compatibility, any more than bringing a D-Star radio would.

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Exactly. Just because krokus is living in the 20th century does not mean the rest of us want to. I quite like digital modes and have no plan to get rid of them, in fact I want to get the CS-800d and replace my analogue only dual band radio.

krokus said:

True, but the whole idea is to have FM there, instead of any digital format.

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Maybe so, but why can't we have and use digital modes as well? Who are you to tell people what modes they can use or not use, What type of repeaters they can put up, using what mode?

The major city I live near, has something like a dozen or more analogue repeaters, one or two YSF, two DMR and three or four D-Star repeaters. most of them sit idle, only ID'ing on their preset timers... at least I can consistently hear activity on DMR even if it is from the network side on World Wide English or North America talk groups.

paulears said:

What a completely misleading video! It has so little to do with what we actually hear. It's a product intended to offer an alternative to echo link, and has a number of different codecs available. It just allows streaming on a narrow band comms link.

It's (at least as far as I can tell) using a FM link used to carry data with a lowish bandwidth, so missing out on many of the benefits of proper digital comms that doesn't use F1E or maybe F2E. Proper digital using FSK is quite different.

The differences from a purely listener perspective are simply the realism the vocoder design can manage. Different brands do it with more or less success than others. Some sound quite human but a little rough sounding while others are easier to listen to, but more robotic and electronic sounding. Some make recognition of individual voices difficult while others manage the subtleties so you can hear accents, or tricky pronunciation. NXDN, MTRBO and most of the DMR radios now do it pretty well. That video just confuses, as it's not really applicable to what we're talking about in general.

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Careful there, don't be jumping to conclusions. I have it on good authority that this software does digital voice and digital amateur television through SDR equipment.
More misleading videos: https://www.youtube.com/watch?v=LUV2zF2pbYU

isn't the initial video simply demonstrating how signal levels drop without dropouts, until the lower margin is found on different codecs? A least, that's what I think it appears to do. It isn't comparing audio quality e to e , just how resilient digital signals can be when the noise rises - which is what digital is always good for. Pretty well this holds true for most forms of digital transmission by radio, cable or fibre - the performance with noisy circuits is still ok, until you reach the danger threshold when it becomes erratic and vanishes quickly, whereas analogue just gets progressively noisier - which we know, I think. The weird sounding audio is not linked to this phenomenon.