Analog vs. Digital

[ASAD]

I was wondering what would be the advatages of digital radios over analog? Do digital radios give a longer range and battery life (if using HT) than analog radios?

What's digital's encryption like? Is it like GSM or just some scrambler similar to that of analog?

Thanks for your help

 

[W7FDX]

Digital generally has clearer transmissions on the fringe areas of the communications range where analog tends to get alot of static. Digital also has more advanced types of encryption. (AES, DES, ADP) vs your basic analog scrambler.

 

[SCPD]

With E adp is typically a scanner buster. Cheap low cost and can be software entry for user at cps. How ever if your a agency it'll cost later as the Feds require to meet any grant funding require aes or des. Aes being most secure des secure. In sense Adp is weak but can do job. However thre is questionable security issues with it. Most won't bother but if you get a tech savy individual there is a issue. Many agencies use des ofb or des xl etc. Digital does sound better and can go further. Just like tv analog you get wavy pictures and some audio. Digital it's all or nothing, then things tend to sound like r2d2. Personally digital is good and I like it. One way to tell is set the same freq in analog then one in digital only. Do a distance check with both having another do count and going location each time with both. One thing with digital is the primary dispatcher is heard clear. But back ground noises can be iffy or sound strange like another person away from mic. Analog you tend to get everyone's voice in background. But in general you only want to hear that one dispatcher not someone ramboing in background which hardly can be made out. Just what I noticed.

 

[W7FDX]

Also with AES and DES they require a KVL or Key Variable Loader which is a very expensive piece of equipment and are tightly regulated that also drives up the cost of secure communications. All in all digital has alot of advantages over analog and in the way LMR comms are all going to be one day.

 

[mikewazowski]

Digital generally has clearer transmissions on the fringe areas of the communications range where analog tends to get alot of static. Digital also has more advanced types of encryption. (AES, DES, ADP) vs your basic analog scrambler.

DES can be used on analog.

 

[wtp]

not a lot of faith

a fireman was standing next to me one day at my job.
we both had on the sarasota florida's fire dispatch which was p-25
we both got to hear r2d2 voice for a dispatched call
i said i could understand it on a scanner but on his....
he said it happens all the time and they just hope it gets better.
that was a while ago and i have lost touch with him, i hope it got better.

 

[RKG]

Somewhat over-simplified:

1) Analog: So long as received signal strength is over a certain level (the "full quieting" level), then because of the clipping effect of FM product detectors, the recovered audio will be perfectly clear, and the sound of the audio will be highly faithful to what one would hear if one were standing next to the sender (spectral fidelity).

2) Analog: As signal strength diminishes from this level, the audio from the receiver speaker will be a mix of sent audio and static, with the proportions increasing toward the latter. For the most part, the speech, or at least its gist, will remain intelligible, particular for a skilled dispatcher, up to the fringe level. Even if signal strength is at the fringe, a frightened sender's tone of voice, coupled with the sender's MDC ID and likely also the dispatch history, will enable a skilled dispatcher to send help his way.

3) Digital: So long as signal strength is above about the same level as analog full quieting, a digital signal will be static-free. However, in most cases spectral fidelity will be impaired (because at LMR carrier frequencies, the digital sampling rate is a small fraction of what is used for, for instance, digital music.) Voices tend to sound a bit "tinny."

4) Digital: In the range of signal strengths between the equivalent of analog "full quieting" and the analog fringe, digital decoding will for the most continue to sound noise free, and this is the basis for claims of "increased range." At the fringe, bit error rate increases very quickly to the point where one gets the "Donald Duck" sound and then no sound or other aural indication that someone is trying to get through at all. Interestingly enough, the sender's ID may show up on the display, but unless the listener is watching the screen, he'll have no indication that someone is trying to get through.

5) Because of the way digital vocoders handle AF values encoding, digital tends not to send pure tones very well (or consistently). This is why, even on some analog systems using infrastructure equipment that uses DSP, QC tones sometimes fail.

6) Likewise, because of the way digitized input audio interfaces with AGC, digital can be swamped by high ambient noise levels proximate to the sender. There are some who believe this problem is endemic to the particular vocoder specified by the APCO P-25 standards (the DVSI IMBE vocoder), and that later generation vocoders are better; I have no knowledge or experience (and, hence, no opinion) on this point.

7) Modern encryption algorithms are based on bit hashing -- which means taking the bits that would be sent by an unencrypted transmission, mixing up the order of the bits in a structured manner by the sender and then unmixing them by the receiver. As applied to natively digital voice transmissions, encryption (both hardware (UCM) and software (ADP) based) imposes no degradation of either audio quality or usable range. Back in the early days of digital encryption as applied to analog signal (e.g., Motorola DVP), encryption required that analog audio be first digitized, then encrypted, then unencrypted, then converted back to analog. DVP imposed both audio and range limitations.

Sorry if this is TMI.

 

[N4DES]

You also have those enhanced signaling and silent identification capabilities when using digital. We use P25 in the amateur band locally, as an example, and use the call alert and user alias' quite extensively and like the additional toys that we can program with ease and silent to the end users.

 

[ff-medic]

DES can be used on analog.

You learn something new everyday. The improvements on DES , are they included also?

FF-Medic !!!

 

[ff-medic]

I was wondering what would be the advatages of digital radios over analog? Do digital radios give a longer range and battery life (if using HT) than analog radios?

What's digital's encryption like? Is it like GSM or just some scrambler similar to that of analog?

Thanks for your help

Digital communication has its pros and cons.

The range for digital communication is not as good as analog ( simplex mode ), but digital communications lets you do a lot of things that you cannot do with analog radio transmissions.

Don't let digital be so depressing. Radio Communications have to advance

http://www.w2sjw.com/radio_sounds.html

http://www.rtl-sdr.com/tag/digital-speech-decoder/

http://wiki.radioreference.com/index.php/Digital_Speech_Decoder_(software_package)



FF-Medic !!!

 

[ff-medic]

Digital Speech Decoder (software package). http://wiki.radioreference.com/index.php/Digital_Speech_Decoder_(software_package)

Contents [hide]
1 Overview
2 Copyright License
3 Patent Issues with mbelib
4 Help Page for Windows
5 Downloads
6 Known Working Hardware Setups
7 Frequently Asked Questions

Overview
Digital Speech Decoder is an open source software package that decodes several digital speech formats. It uses the mbelib library (a separate open source package) to synthesize the decoded digital speech. It does not allow decoding of encrypted communications. It can save the compressed digital audio bits to "mbe" data files (.imb and .amb extensions) and play back those saved files. It's discussed in this forum.


The latest version (1.6) supports the following formats and modulation types:

P25 Phase 1
ProVoice EDACS Digital voice
X2-TDMA - Motorola public safety TDMA system with P25 style signaling (mostly based on DMR)
DMR/MOTOTRBO - Digital Mobile Radio standard
NXDN - 9600 baud (12.5 kHz) NEXEDGE and 4800 baud (6.25 kHz) NEXEDGE/IDAS
D-STAR - The Github version of dsd/mbelib can parse and play back D-STAR traffic.
C4FM modulation
GFSK modulation (including GMSK and other filtered 2/4 level FSK)
QPSK modulation (sometimes marketed as "LSM")
The following formats are currently under investigation or development:
P25 Phase 2 - standard not finalized yet, vocoder is supported by mbelib
OpenSky - four slot format vocoder may be supported by mbelib. Will not be supportable if it is determined that voice encryption is standard .

Other formats will only be considered if high quality samples of the signals are made available for download by the developers. Samples must be from a discriminator tap, .wav format, 48000Hz, 16 bits per sample, mono.
DSD and mbelib should compile on Linux and *BSD operating systems. Any linux distribution should work as long as it has support for your audio devices. DSD version 1.3 and later requires mbelib 1.2 or later.
The forum for discussion of this package can be found here.


Copyright License

DSD and mbelib are both released under a BSD style copyright license. This means that as far as copyrights are concerned it can be freely copied and used, including for commercial products as long as the original copyright notice is included. (However, see important patent issues section below.)
Patent Issues with mbelib

While DSD was intended to be patent-free, mbelib describes functions that may be covered by one or more U.S. patents owned by DVSI Inc. The source code itself should not be infringing as it merely describes possible methods of implementation. Compiling or using mbelib may infringe on patents rights and/or require licensing. It is unknown if DVSI will sell licenses for software that uses mbelib. If you do not have a license and are in a jurisdiction protected by the DVSI patents you should not compile or use this source code.


Help Page for Windows
DSD For Windows Basic Setup - Easy Instructions Noobs Guide
Downloads
dsd-1.6.0
dsd-1.6.0 source download in zip format
mbelib-1.2.5
mbelib-1.2.5 source download in zip format
Windows Binary 1.4.1
Windows Binary
Windows Binary with P25/DMR Filter 1.5.1
Windows Binary
Windows Binary with P25/DMR Filter 1.6.0 Beta
Windows Binary
RTL-SDR.com instructions and download location for DSD+
Windows Binary cygwin.dll not required, lame_enc.dll required for mp3 audio recording (released 12/25/2013)

Note: You'll need cygwin1.dll for all but DSD+. Go to cygwin.com and install it.

Note: Windows binaries listed above are not ports. They are simply the dsd/mbe source compiled on Windows (using CygWin) rather than compiled on Linux.

Note: Cygwin 1.7.26 is broken (/dev/dsp audio device doesn't work)
Note: DSD 1.6 source from Github (at least on 12-15-2013) was broken - Minimal if any P25 output
DSD on Github
Known Working Hardware Setups
If this list gets large enough I will move it to its own page so as not to detract from the overview of DSD.
Discriminator Source Input Input Sound Device Output Sound Device Operating System/ Linux Flavor Computer Specs Audio Successfully Decoded
GRE PSR-500 Direct Tap iMic mic port iMic Onboard audio Ubuntu 10.04 Dell Mini 1012 netbook N450(1.66GHz) ProVoice
TV28T v2 DVB-T USB Stick (R820T) What You Hear Soundblaster Audigy (PCI) Onboard Audio Windows XP Pro Intel DG41TY mobo w/ Intel Core2 Quad CPU Q9400 (2.66GHz) P25 Phase 1, MotoTRBO
RadioShack Pro-97 Direct Tap Line In Realtek HD Audio Realtek HD Audio Ubuntu 10.04 Acer Aspire One Netbook D150 (1.7 GHz) P25 Phase I
RadioShack Pro-95 Direct Tap w/10k Resistor Line In iMic & Realtek HD Audio iMic & Realtek HD Audio Ubuntu 10.04 Custom Built/ Gigabyte Motherboard P25 Phase I, Provoice
RadioShack Pro-95 Disc Tap Line in G110 Keyboard G110 Keyboard Windows 7 EVGA x58/i7 920 Provoice
RadioShack Pro-94 Direct Tap Line In Realtek HD Audio Realtek HD Audio Ubuntu 10.04 Custom Built/ Gigabyte Motherboard P25 Phase I
RadioShack Pro-90 Disc Tap Line In AC97 AC97 Ubuntu 10.4 3 GHz 1.5MB P25 Phase I
RadioShack Pro-79 Direct Tap Line In Analog Devices ADI 198x Integrated Audio/SoundBlaster Live!32 Analog Devices ADI 198x Integrated Audio/SoundBlaster Live!32 Xubuntu 9.10/Ubuntu 10.04 Dell GX270 (P4 2.6 GHz)/Lenovo Thinkpad X61 (Core 2 Duo)/Dell Precision 300 (P4 3.2 GHz) P25 Phase I, ProVoice, MotoTRBO
RadioShack Pro-2067 Direct Tap Line In Analog Devices ADI 198x Integrated Audio Analog Devices ADI 198x Integrated Audio Ubuntu 10.04 Dell GX520 (2.8 GHz - 3.4 GHz) MotoTRBO, ProVoice
RadioShack Pro-433 Disc Tap Line in Intel HD Audio Intel HD Audio Ubuntu 11.04 Dell Inspiron 1525 Core 2 Duo MotoTRBO
Icom IC-PCR1000 Packet out w/100k ohm resistor and 10uf capacitor built into cable Line In AC97 Diamond XS71 Ubuntu 10.04 Amd Athlon 64 (1.8 GHz - 2.4 GHz) P25 Phase I, MotoTRBO
Icom IC-PCR1000 Packet output Line In AC97 Sound Blaster X-Fi Debian Lenny Athlon 64 3000+ (2.0 GHz) Provoice, MotoTRBO, P25 Phase I
Uniden BCT15X Line In AC97 Sound Blaster X-Fi Debian Lenny Athlon 64 3000+ (2.0 GHz) Provoice, MotoTRBO, P25 Phase I
Uniden BCT-15X Disc Tap Mic In (DC Bias removed) C-Media CM108 ($1.87 on eBay) C-Media CM108 ($1.87 on eBay) Windows 7 Pro IBM x336 dual Xeon 3.0GHz ProVoice, DMR, P25 Phase I
Uniden BCT-15 Disc Tap Mic in ATI Sound Max Ubuntu 10.4 2.4 GHz Core 2 Duo 4.0MB P25 Phase I
Uniden BCT-8 Disc Tap Line In Realtek HD Audio Sound Blaster X-Fi Windows 7 i7-3960X 3.30GHz MotoTRBO
Uniden BC796D Disc Tap Line in Sound Blaster X-Fi Sound Blaster X-Fi Windows 7 HP Pavillion Elite, Intel i7 quad core P25 Phase 1, ProVoice, MotoTRBO
Uniden BC350A Direct Tap Line In RealTek HD Audio RealTek HD Audio Ubuntu 10.04 32-bit AMD Turion 64 X2 (2.0 GHz) MotoTRBO, NXDN 4800
Uniden BC246T Disc Tap w/100k ohm resistor and 10uf capacitor built into cable Line In AC97 AC97 Ubuntu 10.04 on flash drive Dell Dimension 2400 (2.4 GHz - 2.8 GHz) P25 Phase I
Uniden BC245xlt Direct Tap iMic mic port iMic Onboard audio Ubuntu 10.04 Dell Mini 1012 netbook N450(1.66GHz) ProVoice
Uniden BC235xlt Direct Tap iMic mic port iMic Onboard audio Ubuntu 10.04 Dell Mini 1012 netbook N450(1.66GHz) ProVoice
Yaesu ft857 packet socket Line In snd_hda_intel snd_usb_audio Ubuntu 9.1 32bit AMD Athlon 64x2 8400+ (2.1 GHz) MotoTRBO
Yaesu FT8800 Disc Tap Line In AC97 AC97 Debian (no GUI) 1.7 GHz Athlon MotoTRBO, P25 Phase I
AOR AR-2515 Disc Tap Line In AC97 AC97 Ubuntu 10.4 3 GHz 1.5MB P25 Phase I
Kenwood TH-F6A 9600 baud out w/100k ohm resistor and 10uf capacitor built into cable Mic in AC97 AC97 Ubuntu 10.04 Acer Aspire One P25 Phase I, MotoTRBO
Uniden BCT15X Disc Tap 10k ohm resistor and 10uf capacitor Line In SoundMAX Integrated Digital HD Audio SoundMAX Integrated Digital HD Audio Windows 8 Pro Athlon 64 6400+ (3.1 GHz) P25 Phase I NXDN 9600
Uniden BC346XT Disc Tap 10k ohm resistor Line In Realtek HD Audio Realtek HD Audio Windows 7 64 Intel i5-2500 (3.3 GHz) Provoice, P25 Phase I, DMR
ICOM IC-7100 USB Sound output USB USB Audio Codec Realtek HD Audio Windows 7 32 Intel P9700 (2.8 GHz) P25 Phase I, DMR
DVT-SDR with SDR# USB VB Audio Virtual Cable Onboard Audio Windows 8.1 Pro Microsoft Surface Pro (first gen). Intel i5. MotoTRBO, P25
Frequently Asked Questions
Q: Do I need a radio with discriminator tap?
A: Yes, if you want to listen live or save mbe data files. No radio or discriminator tap is required to play saved mbe data files.
Q: Where can I get information on the discriminator tap for my radio?
A: Wiki information is available here for the Discriminator_output.
Q: Will this work on Windows?
A: As of December 7, 2011 binaries for Windows have been added.
Q: Will this work on a Mac?
A: No, because OS X does not use the traditional Unix-like /dev/audio interface. It should be easy for someone familiar with Mac audio programming to port it to the Mac.
Q: Will you support decryption if I lawfully posess the encryption keys?
A: From the Readme file:
Decryption of speech is NOT supported, even if you lawfully posess the
encryption keys. Decryption support will not be added in the future as
the authors wish to steer as far away from the legal issues associated
with encryption as possible.
Q: Who are the author(s)?'
A: The author(s) are anonymous but PGP keys are provided inside the packages so future releases/communications can be verified.
Category: Software Applications

FF-Medic !!!

 

[freddaniel]

The Subject Is: Analog vs. Digital

If the user group does not need encryption, then a narrowband ANALOG system can be built for a fraction of a fraction of the cost of a digital system. When viewing the total cost of all user radios and the network/repeater equipment in total, analog is still robust, with excellent audio clarity. In quantity, type-accepted analog radios can be had for way under $100 each. That leaves a lot of cash to build an outstanding network, with receiver voting and simulcast, if required.

I know, digital is really neat, but Analog was abandon, not improved upon.

 

[sloop]

Analog vs. digital can be "discussed" forever with out changing the fact...narrow band digital trunking is here to stay regardless of its worth. The only good thing I can say about digital is that when you can hear it, it sounds good. For over 25 years (until I retired) I have been involved in government operations of some kind. As a Park Ranger the analog system that we used could be accessed with full quieting from 150 miles away. When we were switched over to a narrow band digital trunked system we could not communicate from one end of the lake on our project to the other. As a Park Ranger, Firefighter, EMT my life (as well as others) need a system that works, not one that sounds good when it works. If you can find the original 9-11 report (before it was 'revised') one of the major problems in communications cited was the inability of the radio system (digital trunked) to operate inside the buildings that caused a lot of confusion and cost lives. But as long as the government mandates (and funds) this type of system that is what we will have. At last check Yellowstone National Park still used analog as their main system in the park (Office area is digital) becaused the other system was not usable. Sorry for the rant and I hope that I have not offended anyone...it was not my intention if I did.

 

[JRayfield]

Time and time again, users who have switched from wideband analog to narrowband analog have suffered a serious drop in range (as much as 25% to 30%). Given the same parameters (transmit power, antennas, sites, etc), digital systems (such as MOTOTRBO) will provide better range than narrowband analog.

As to cost of analog radios, sure there are 'cheap' analog radios on the market, such as the Baofeng units. But they're not near the quality of higher priced units (such as Motorola XPR-series units). If comparing the same 'tier' of radios (in terms of quality and features), analog vs. digital/analog, the digital models will often be about the same, or even less in some cases, than older analog-only units. As to the cost of infrastructure, the cost for 'quality' analog infrastructure is higher than similar-quality digital infrastructure.

John Rayfield, Jr. CETma

The Subject Is: Analog vs. Digital

If the user group does not need encryption, then a narrowband ANALOG system can be built for a fraction of a fraction of the cost of a digital system. When viewing the total cost of all user radios and the network/repeater equipment in total, analog is still robust, with excellent audio clarity. In quantity, type-accepted analog radios can be had for way under $100 each. That leaves a lot of cash to build an outstanding network, with receiver voting and simulcast, if required.

I know, digital is really neat, but Analog was abandon, not improved upon.

 

[MTS2000des]

My testing with DMR shows at least DMR (MotoTRBO) gives a huge advantage over narrowband analog.

At my hospital, I can reliably hear and hit a TRBO ham system from inside the basement despite the signal being about -116dbm. On analog from the same site, the signal was so overridden with noise, there was no readability.

when the repeater was an analog MTR2000 running 80 watts, it still had less coverage than it does now at 40 watts on DMR. Same duplexer, same feedline, same antenna, same location. Yes, the MTR was fully in spec.

True, that once you go over the "digital cliff" you get nothing. But in my experience with MotoTRBO, that "cliff" is so far beyond "down in the dirt" if you were on analog narrowband FM from the same location, it doesn't really matter.