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  #41 (permalink)  
Old 05-10-2017, 2:24 PM
  Amateur Radio Operator
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Join Date: Jan 2015
Posts: 80

Originally Posted by RFI-EMI-GUY View Post
I have an HP536BCD and the internal speaker is crap. So I have a Motorola Spectra speaker attached and it behaves much better. Headphones are even better. Aside from occasional simulcast TDI, it normally sounds good. Dispatch is generally very readable. Some users voices do not translate well through the P25 IMBE Vocoder and are muffled. Also fast talkers seem to bring down the Vocoder performance.

Wideband FM is still king, I played around with some ancient Securenet DES recently and compared to P25 it is not all that bad. There is quantization noise, no denying that. However there is virtually no throughput delay and voice recognition is good.
Does IMBE suffer as much as AMBE from popping?

I found that DMR has problems with such sounds.
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  #42 (permalink)  
Old 05-10-2017, 3:29 PM
stmills's Avatar
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Join Date: Dec 2002
Location: Twin Cites Area MN
Posts: 802

I find it interesting that on the info for the LEX 10 and LEX700 MissionCritical Smartphones Motorola advertises them as a companion to your two way Radio and as a way for administration to be in touch with agents in the field on there two way Radio.
Steve Mills EMT-B
Twin Cities Incident Page-TCIP
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  #43 (permalink)  
Old 05-10-2017, 3:50 PM
Join Date: Mar 2014
Posts: 252

Originally Posted by jim202 View Post
What P25 system are you trying to listen to? All the numerous ones that I have been able to work with all sound fine. The audio is clean and not distorted.

I do have to inject a slight negative here also. If the radio techs didn't do their due diligence on aligning a simulcast system, then you could have issues in the tower overlap regions with distorted audio. But that is not the norm for a well adjusted system.

If a system does have these problems, then the radio manager needs to get on the case of the radio vendor and get them corrected.
I've heard P25 on several systems.All have the same basic audio quality.Many people just get use to it and don't complain anymore.Most PD and FD users initially complain about the audio quality once switched over to P25 and then after finding out that there is nothing that can really be done about it,generally stop complaining.

Originally Posted by milf View Post
Folks still don't get it. Scanners never will sound or work like an actual system radio on p25.

Sent from my LG-K330 using Tapatalk

I'm not basing my observations on scanners or hobby SDR's.

Originally Posted by BIODTL1997 View Post
".I still don't know how P25 ever managed to be considered acceptable for federal or public safety applications.It's usually a squawky unintelligible mess compared to analog."

P25 sounds perfectly good on every Motorola radio I/I've owned. If you're basing that observation on a scanner, yes, it can certainly be a mess.
No scanners.P25 radios.Harris/M/A-COM,Thales etc...

Originally Posted by RFI-EMI-GUY View Post
Some users voices do not translate well through the P25 IMBE Vocoder and are muffled. Also fast talkers seem to bring down the Vocoder performance.
Yep,I've noticed the same on several systems using P25 capable radios.It also happens with AMBE+2 vocoders.
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  #44 (permalink)  
Old 05-10-2017, 7:50 PM
Join Date: Mar 2010
Posts: 685

Originally Posted by DaveNF2G View Post
Cellphones are great if: You are near a major city; You are near an Interstate Highway; The power has been off for less than half a day.
On top of that, a lot of sites use fiber for the backhaul. Another major failure point. Even if the site has generator backup, the CIC cabinets the phone company use run on battery, so even a prolonged simple power outage can render the site useless. Never mind the risk of fiber damage or anything else.
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  #45 (permalink)  
Old 05-13-2017, 9:55 AM
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Join Date: Sep 2004
Posts: 786

I agree with what many of you are saying about cellular coverage vs. LMR, backup, load etc.

HOWEVER, that being said the assumption being made here is that Wave will replace the FBI LMR system instead of simply enhancing their coverage. FBI LMR does not have anything near nationwide coverage and, once you get outside of major metro areas, it is designed to support 100 watt car radios- not portable coverage. So, they have had to work around this problem. In many cases FBI is piggybacking on state and local radio systems- which causes its own set of issues depending on which lawyer is involved and all the coordination problems that go with it.

IMHO using Wave to extend FBI coverage and service is logical. It is not a replacement for LMR- at least not the way things stand now.
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  #46 (permalink)  
Old 05-15-2017, 12:52 AM
Join Date: Jun 2002
Location: Object-oriented
Posts: 546

An amendment to my previous post- I drove I-5 from Seattle to San Diego over last week, and I can see where this would be an issue.

I lost LTE coverage in the Southern Oregon mountains for nearly 10 minutes on Tuesday (fringe area), and for another 5 minutes north of Shasta Dam on Wednesday (fringe area). 15 minutes total over 1408.1 miles. I was using Zello PTT nearly the entire trip.

The AT&T network never seemed to have an issue, even during LA rush hour when I likely would've enjoyed being cell-free for a little while.
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  #47 (permalink)  
Old 05-21-2017, 2:43 PM
Join Date: Jul 2009
Location: suburban hell
Posts: 396

a few years ago the fbi had their wiretaps turned off because they were not paying their bills. do you think they are going to have the money for unlimited data too?
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