Can someone explain cellphone vs digital scanners?

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scanmanmi

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I don't understand how a digital cellphone can sound so clear and this digital scanner sounds like poop; if it isn't even garbled. Is it baudrate or modulation? What's the difference and will phse 2 be any better?
 

ShyFlyer

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Think of your cellphone as a professional grade digital two-way radio with trunking and encryption capability. A pro-grade radio operating on the system it was designed to operate on will always sound better than one that is essentially assuming that all systems are created the same. Which they are not.

For the record, with the default settings, my 436 works wonderfully monitoring the systems in use here in the Denver Metro. There may come a time when I happen to monitor a system outside this area that the scanner performs poorly on without tweaking the various settings in the menus.
 

Spitfire8520

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I don't understand how a digital cellphone can sound so clear and this digital scanner sounds like poop; if it isn't even garbled. Is it baudrate or modulation? What's the difference and will phse 2 be any better?
It is probably due to a difference in bit rate. Keep in mind that different codecs being used also affects the audio quality.

Many cell networks encodes and transmits voice at around 12.65 kbit/s.
P25 Phase 1 encodes and transmits voice at 7.2 kbit/s.
P25 Phase 2 encodes and transmits voice at 3.6 kbit/s.

Less bits means less data is available to recreate good sounding audio.
 

ShyFlyer

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I monitor both a Phase I system (CO-DTRS) and a Phase II system (Aurora P-25) and honestly can't tell the difference between the two as far as voice quality goes.
 

ofd8001

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Whether Phase 2 is better or worse is in the ear of the beholder. Yeah this is off the wall, but what sounds good to someone sounds horrible to another.

Cell phones are designed for specific types of digitizing the transmissions they send and receive. Scanners deal with a greater variery of digital decoding as well as a couple of types of FM demodulation and AM. Kind of along the lines of going to a general practioner physician for heart surgery.
 
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Phase 2 has half the bandwidth of phase 1

536/436/ws1095/996p2/996xt/325p2/396xt/psr800/396t/HP-1/HP-2 & others
False. The throughput is less due to the nature of TDMA but the bandwidth is almost the same in terms of spectrum. Phase 1 operates at a 9600 bps data rate for both uplink and downlink. Phase 2 on the other hand operates on a 12000 bps downlink and 6000 bps uplink. In other words, the SU has to decode 12000 bps from the repeater (remember, same 9600 bps control channel Phase 1 uses) but only has to transmit at 6000 bps.

Newer cell phones running VoLTE have a data rate of 64,000 bps on a much wider channel (measured in MHz) compared to 12.5 kha and narrower solutions.



Sent from my SM-T713 using Tapatalk
 

marcotor

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I have never had problems understanding digital voice on any of my Motorola, or EFJ, handheld and mobile radios.
 

12dbsinad

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You've obviously never lived in a rural area where static was the predominant component of analog cell audio...
This is true. However, you knew when you are getting to the fringe. Today, it just dumps you, no warning or maybe a slight garble. If you had a good signal I still feel analog cell sounded WAY better than today's compressed cell audio.

The other problem I find is that 4G stinks in rural areas. I keep my phone locked on 3G because it will out talk 4G by far. The other stinker is that the phone will not switch between 3 and 4, even if you have a good signal on 3 without dumping the call, it switches, then you can call back and continue on with the convo. In cities and populated areas 4G seems to work OK as it has enough saturation.

I miss my 3 watt cellphone sometimes...
 
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