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  #21 (permalink)  
Old 09-13-2017, 8:18 AM
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Originally Posted by RFI-EMI-GUY View Post
When I was FTR, during the roll out of Smartnet 1 we were sweating 500 milliseconds access time. Then P25 rolled out and added over 160 milliseconds IMBE latency to turn voice into concentrated orange juice, load it on the truck, transport it across town , add water and then reconstitute the finished product.

2100 milliseconds is just way too much for any sort of tactical application. And wasteful of human resources during a dispatch environment.

Satellite telephony got phased out to transatlantic fiber, because the delay to/from a geostationary satellite was unnatural to users. That delay was in the order of 250 ms (I am probably a bit off, not bothering to calculate today, post Irma).

This 2100 milliseconds is crazy, Skype isn't even that bad. OK maybe in half duplex it isn't that noticeable, however it does significantly delay tactical response and might I remind you all, in a dispatch situation, those missing seconds add up to a huge backlog of calls for service. Think carefully about the erlang, not in the context of the transmission media, but in the unavailability of the channel during those seconds between exchanges in a message. Imagine dispatching a huge fleet during a busy hour and each and every 4 to 6 second transaction taking an extra 1.5 seconds.

It is dumb dumb dumb. Design engineers need to sit in a dispatch center for a week.





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It is due to software DSP. Hardware DSP isn't nearly as bad (I've actually talked to some of Motorola's cellular engineers who've worked on FirstNet and Wave gear) but it puts the price of the handset in the $5000 range currently to equip a cellular device with hardware DSP.
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Old 09-13-2017, 9:35 AM
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Originally Posted by MCore25 View Post
It is due to software DSP. Hardware DSP isn't nearly as bad (I've actually talked to some of Motorola's cellular engineers who've worked on FirstNet and Wave gear) but it puts the price of the handset in the $5000 range currently to equip a cellular device with hardware DSP.
Are we talking about Vocoder DSP? I don't know of any cellphones with 2100 ms latency, so they must have HW DSP already for normal operation. Sounds like Wave is not ready for primetime.

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Old 09-13-2017, 9:49 AM
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Are we talking about Vocoder DSP? I don't know of any cellphones with 2100 ms latency, so they must have HW DSP already for normal operation. Sounds like Wave is not ready for primetime.

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Currently all PTToLTE solutions have that kind of latency. ESChat, ePTT, Wave, Zello...it's not really a limitation of the gateways but a limitation of the site and SU hardware on the LTE side. We aren't talking about acquisition time, but time it takes spoken voice to be encoded, transmitted across the network, decoded and played. Even on a phone call, you're looking at about 1 second of delay over LTE currently.
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Old 09-13-2017, 10:16 AM
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Originally Posted by MCore25 View Post
Currently all PTToLTE solutions have that kind of latency. ESChat, ePTT, Wave, Zello...it's not really a limitation of the gateways but a limitation of the site and SU hardware on the LTE side. We aren't talking about acquisition time, but time it takes spoken voice to be encoded, transmitted across the network, decoded and played. Even on a phone call, you're looking at about 1 second of delay over LTE currently.
It is really not good enough.

Regarding cellphones, my 2006 vintage CDMA phone has just enough latency to create confusion during a lively conversation. Bump that up to 1 second and it will be downright annoying, no wonder people prefer to text!

POTS phones, you do remember POTS phones? Those are the ones with copper wires, a central office with batteries and "toll grade" (you don't hear that term any longer) multiplex, had excellent fidelity, and no perceptible latency.

We are sliding backward in performance. We have the mobility solution solved, but with a terrible penalty in quality. Do people not care about quality any longer? Is it all just a price breakpoint? We must have the latest technology, we will pay as little as possible for the cheapest mediocre solution as long as it is shiny and new?

Is it a sign of our declining instant gratification, society? Why drive to that great greasy spoon in the next neighborhood, when I can get a lousy egg McDuffin by walking to the corner?

Just say no to VoLTE......

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Old 09-13-2017, 5:58 PM
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We have been playing with various inexpensive Android PTT devices (Radio Tone RT3, etc) running Harris BeON from our P25 VIDA network. The target would be for teachers inside schools as all of our schools have full coverage Enterprise WiFi. So far the result is pretty damn good for the application we are just waiting on word from TAC regarding some custom button mapping features before a field trial.

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Old 09-13-2017, 6:14 PM
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We have been playing with various inexpensive Android PTT devices (Radio Tone RT3, etc) running Harris BeON from our P25 VIDA network. The target would be for teachers inside schools as all of our schools have full coverage Enterprise WiFi. So far the result is pretty damn good for the application we are just waiting on word from TAC regarding some custom button mapping features before a field trial.

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Where are you buying them from and what price range? Is it a "true PTT" for Zello and BeOn or is that why you need to map the buttons?
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Old 09-13-2017, 6:45 PM
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The couple I got to play with were Amazon specials in the sub $150 range. They are designed for Zello.
http://www.radio-tone.com/rds01_product.php?id=110416


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Old 09-13-2017, 6:50 PM
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Some devices are on the market with good separate button PTT..

Zebra''s TC55 which was a Motorola profuct.

The Sonim Technologies

An Motorola LEX F10.

........
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Old 09-13-2017, 7:18 PM
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Originally Posted by Firebuff880 View Post
Some devices are on the market with good separate button PTT..



Zebra''s TC55 which was a Motorola profuct.



The Sonim Technologies



An Motorola LEX F10.



........


Kyocera as well (I'm not fond of their phone integration).


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Old 09-14-2017, 9:25 AM
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The couple I got to play with were Amazon specials in the sub $150 range. They are designed for Zello.
RADIO-TONE


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How is the "build quality" of the Radio Tone Products - fairly solid or crappy?

So fay I have not had a client express interest in RoIP radios but at some point I figure somebody will read about it and ask us. Sometimes a customer will even buy a bunch of stuff like this and call us when they can't make it work. Eventually we will probably buy some kind of RoIP radio demo kit to play with.
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Old 09-14-2017, 9:57 AM
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Originally Posted by LubeckTech View Post
How is the "build quality" of the Radio Tone Products - fairly solid or crappy?

So fay I have not had a client express interest in RoIP radios but at some point I figure somebody will read about it and ask us. Sometimes a customer will even buy a bunch of stuff like this and call us when they can't make it work. Eventually we will probably buy some kind of RoIP radio demo kit to play with.
So far, for what they are, I'm fairly impressed. Fairly well built in terms of materials, small, light and looks more like a radio that is designed to clip to the hip than a phone.

The down side is that they run Android 4.4 (current release is 8) and the screen is somewhat underwhelming.

The nitch that it would fill for us is based on a need for an FRS size/weight device that is low cost and can be integrated with our P25 system in a non-mission critical setting that is blanketed with Enterprise WiFi.

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Old 09-14-2017, 2:02 PM
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>>Design engineers need to sit in a dispatch center for a week.

Years ago I was working a race in Miami when some Motorola engineers came into the truck introduce themselves and see what how radios worked in race cars. I was tuning an MX-330 and they wanted to watch me go through the process. As I was tuning the xmtr one guy asked what I was doing.
I told him I was 'warping the transmitter', the term warping was in the MX manual. He asked me what warping meant, I said "you guys wrote the manual, you tell me."

He had never seen a radio tuned and found the process very interesting. Up to that point I was under the impression engineers could walk on water.
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