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  #41 (permalink)  
Old 05-10-2017, 3:24 PM
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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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Old 05-10-2017, 4:29 PM
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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.
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  #43 (permalink)  
Old 05-10-2017, 4:50 PM
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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.

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Folks still don't get it. Scanners never will sound or work like an actual system radio on p25.

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

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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...

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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, 8:50 PM
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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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Old 05-13-2017, 10:55 AM
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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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Old 05-15-2017, 1:52 AM
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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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Old 05-21-2017, 3:43 PM
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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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Old 06-22-2017, 12:04 AM
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Default You can thank FirstNet for this ludicrous operation plan

Granted- I did not read all of the posts in this thread first, so pardon me if I am stating what's already been said in it.

FirstNet, already costing 47$ billions and not even out the door. This is the plan Feds will be using- VoIP, and- to beat all- data will be "in the cloud". What could possibly go wrong?

FirstNet will absorb both local PD, Fire, EMS, FBI, Homeland Sec/ICE whatever they call themselves these days- all of Fed, State, City, regional altogether kumbaya on one gargantuan "system". System in quotes intentional. System of systems. Those who know about systems know what I am talking about. Or, those old fuddy duddies who watch boring stuff like C SPAN and read reports. https://www.firstnet.gov/newsroom/bl...rst-responders
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Old 06-22-2017, 9:52 AM
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Originally Posted by fleef View Post
Granted- I did not read all of the posts in this thread first, so pardon me if I am stating what's already been said in it.

FirstNet, already costing 47$ billions and not even out the door. This is the plan Feds will be using- VoIP, and- to beat all- data will be "in the cloud". What could possibly go wrong?

FirstNet will absorb both local PD, Fire, EMS, FBI, Homeland Sec/ICE whatever they call themselves these days- all of Fed, State, City, regional altogether kumbaya on one gargantuan "system". System in quotes intentional. System of systems. Those who know about systems know what I am talking about. Or, those old fuddy duddies who watch boring stuff like C SPAN and read reports. https://www.firstnet.gov/newsroom/bl...rst-responders

One system to rule them all! LOL!
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Old 06-22-2017, 9:59 AM
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Sounds like a very expensive single point of failure.
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Old 06-22-2017, 10:01 AM
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Make that a thousand points of failure shining in coffers of government employees

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  #52 (permalink)  
Old 06-23-2017, 11:37 AM
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I remember when 9-11 happened Bush flew to Barksdale AFB in North Louisiana. I got into a conversation with others in my profession who travel all over the state and they all talked about how all the cellular carriers within about a 50 mile radius of Barksdale were being jammed during the time Bush was at Barksdale. No one could make or recieve any calls or texts and it affected all carriers. There is often an E-4 airborne command post aircraft at Barksdale and it more than likely has the ability to jam cellular communications. Well, if the FBI has to respond to some type of big crisis and the air force jams the cellular communications again, then the FBI will be up s-bomb creek for communications if that's all they have. It's laughable. Can you say keystone cops?
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Old 06-23-2017, 11:50 AM
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Just another possibility - everyone and anyone was talking to their cousin, friends, family etc and the network was overloaded.

During the Boston Bombing there were "FALSE" reports that the network was being jammed to prevent additional devices from going off. Turned out to be the network could not handle the traffic. Which is why SMS would still work, as well as those who used GETS WPS
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I remember when 9-11 happened Bush flew to Barksdale AFB in North Louisiana. I got into a conversation with others in my profession who travel all over the state and they all talked about how all the cellular carriers within about a 50 mile radius of Barksdale were being jammed during the time Bush was at Barksdale. No one could make or recieve any calls or texts and it affected all carriers. There is often an E-4 airborne command post aircraft at Barksdale and it more than likely has the ability to jam cellular communications. Well, if the FBI has to respond to some type of big crisis and the air force jams the cellular communications again, then the FBI will be up s-bomb creek for communications if that's all they have. It's laughable. Can you say keystone cops?
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Old 06-23-2017, 11:53 AM
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That's a good possiblilty too. Which is why when we have to do hurricane evacuations I always bring two-way radios for car to car communications. During the Katrina evacuation people could not get through.
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Old 06-23-2017, 12:56 PM
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I believe this is going on because twice here in central Florida, during the election cycle, when President Obama's motorcade was traveling through, I witnessed what might be barrage jamming on my car FM broadcast radio. The first time this happened, my wife was trying to call my cellphone at same time and could not get through. This is probably done to disrupt IED's.
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I remember when 9-11 happened Bush flew to Barksdale AFB in North Louisiana. I got into a conversation with others in my profession who travel all over the state and they all talked about how all the cellular carriers within about a 50 mile radius of Barksdale were being jammed during the time Bush was at Barksdale. No one could make or recieve any calls or texts and it affected all carriers. There is often an E-4 airborne command post aircraft at Barksdale and it more than likely has the ability to jam cellular communications. Well, if the FBI has to respond to some type of big crisis and the air force jams the cellular communications again, then the FBI will be up s-bomb creek for communications if that's all they have. It's laughable. Can you say keystone cops?

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Old 06-25-2017, 10:05 PM
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Originally Posted by Tim-B View Post
I remember when 9-11 happened Bush flew to Barksdale AFB in North Louisiana. I got into a conversation with others in my profession who travel all over the state and they all talked about how all the cellular carriers within about a 50 mile radius of Barksdale were being jammed during the time Bush was at Barksdale. No one could make or recieve any calls or texts and it affected all carriers. There is often an E-4 airborne command post aircraft at Barksdale and it more than likely has the ability to jam cellular communications. Well, if the FBI has to respond to some type of big crisis and the air force jams the cellular communications again, then the FBI will be up s-bomb creek for communications if that's all they have. It's laughable. Can you say keystone cops?
I can say "keystone cops" just fine but after reading your post, "looney tunes" rolls off the tongue much louder & easier.

Telco circuits all over the county were saturated or close-to it on 9/11 by people like us who called friends & relatives to say "Quick, turn on your TV!" etc.

Dare I ask what background you have to smugly suggest that E-4Bs have "cellular communications" electronic countermeasures capability, or should I just refer myself back to my first sentence?


FirstNet uses LTE but in spectrum set-aside for public safety so any coherent jamming of RF systems should keep that in-mind, as-is already the case. FirstNet will be great for populated areas -- Super Bowl, Denver, etc. but first-responders will need to have some sort of traditional direct/repeater land mobile radio capability for incidents way out in the boonies that don't & won't have AT&T FirstNet coverage until the comms support people arrive with portable LTE base stations.
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Last edited by Hooligan; 06-25-2017 at 10:16 PM..
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Old 06-25-2017, 10:21 PM
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There is nothing "smug" about it. It's as simple as two plus two equals four.

Just observe the facts:

-On 9-11 Bush left Florida and flew to Barksdale.
-One of the people that I talked to said that shortly before he arrived that they saw the "white 747" as she described take off and begin to orbit.
-The group I was talking with compared notes and they all agreed that at about that time they could not place nor receive cellular calls or texts and some of the people phones said "no service" on the display which would NOT happen if it was simply a network where "all circuits were busy"
-The inability to receive calls or texts continued for the short duration of Bush's visit.
-A few minutes after the news said that he left Barksdale enroute to Offut their cellular service was restored.
-We compared notes and each person asked the rest in the group where they were and where were the other people they knew who could not place or receive calls. The locations were all in about a fifty mile radius of Barksdale.
-Other people they knew outside that radius could make and receive calls and texts just fine.


Draw your own conclusions. Either one of two things happened:
- Either both 800 MHz cellular carriers and all 6 PCS carriers within a 50 mile radius of Barksdale had an outage and the same time and it was just a coincidence
or
- The U.S. Govt has the ability to jam cellular networks.

Which do you think sounds more likely?

Oh, and by the way Mr. Troll, a few time while perusing Govt.bid requests online I have come across bid requests for cellular jamming equipment to be used in the field by the military. And yes I know CDMA is spread spectrum but you CAN jam a spread spectrum signal if you have the pseudo random noise codes and since all of those are known for an industry standard like CDMA then jamming them is not difficult.
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Old 06-25-2017, 11:14 PM
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https://en.m.wikipedia.org/wiki/USSS...sures_Suburban

http://www.politico.com/magazine/sto...sort-of-114647

http://mt-fedfiles.blogspot.com/2010...e-jamming.html

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Old 06-26-2017, 2:30 AM
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Originally Posted by KE4NYV View Post
On Wednesday I attended a conference in Arlington, VA put on by Motorola for federal agencies (I was there to represent NASA) regarding their WAVE gateway for interfacing cellular to LMR. The FBI gave a very interested presentation about how they have moved a good percentage of the agency over to this system and plan to move the entire agency over within the next couple of years. Bad news for us, since a majority of this will not be simulcasted over LMR and instead kept to the cellular side.

The two main arguments for it was covertness (Essentially looking like just any other guy with a smart phone and ear buds) and they complained that many areas their two-way will not work (such as dense buildings and underground subways) and the cellular keeps going.

Very interesting.
The FBI, nor a number of other agencies have no plans to get rid of, or stop maintaining their existing repeater system. If they are working an operation where they normally would use the LMR system, they will, but it may be intermingled with someone participating from their cell phone, their desk phone, their computer, etc.

They are still expanding right now their repeater system.
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Old 06-29-2017, 10:01 PM
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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.
Cell phone and internet outages at NC coast after fiber line cut | WNCN

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