Tennessee and Georgia have completed a monumental project designed to save lives and

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b7spectra

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I am real curious on how during this "roll call" someone in Atlanta was able to connect to a system 80-100 miles away on 700/800 MHz! Yes, Cobb can add TG's to their system for the users in other jurisdictions, but those agencies are going to have to program in the Cobb DTRS.
 

jim202

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When I first read what had been posted by 123easy, my gut feeling was this smelled like a Motorola
smartzone trunking system. In watching the video clip, I was able to see the new radios at the start
of the clip and that confirmed it. Then in the clip you heard and saw the Motorola name.

How the smartzone system works is it has a number of talkgroups that can be placed on the system.
Some of these may be set up for system wide operation. When one radio comes up on that talkgroup,
not only is it re-transmitted locally to the radio, but comes out on every site in the system. This
allows for anyone on that talkgroup to hear and be heard system wide. Other talkgroups would
normally be limited to the local area that they need to cover only. It may be just one site or a couple
or maybe even three or four sites. Each talkgroup can be set up differently to cover just the area
that it needs to cover.

If a user leaves their normal area, the system keeps track where that radio goes and turns on the
local site that the radio registers into. As the radio moves along into another site coverage area,
that site then provides his talkgroup. So you can go any place in the system and stay on your
local talkgroup.

Jim




I am real curious on how during this "roll call" someone in Atlanta was able to connect to a system 80-100 miles away on 700/800 MHz! Yes, Cobb can add TG's to their system for the users in other jurisdictions, but those agencies are going to have to program in the Cobb DTRS.
 

n5ims

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I am real curious on how during this "roll call" someone in Atlanta was able to connect to a system 80-100 miles away on 700/800 MHz! Yes, Cobb can add TG's to their system for the users in other jurisdictions, but those agencies are going to have to program in the Cobb DTRS.
Bob in Atlanta uses their radio on the "site-wide" talkgroup and their local repeater's receiver sends the signal to their system's controller. Since the "site-wide" talkgroup was selected, the controller sends the signal out over the system's digital links to all other repeaters which then repeat the transmission. Sally in Nashville then hears the transmission on her local system. She may then respond normally and the process repeats.
 

monitor142

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SKYNET156, yes the APX7000 portables are shown on the video. The info shown at the "key hand over" indicates a Motorola ASTRO25 Integrated Voice and Data (IV&D) system.

-M142
 

AndrewCicotte

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No digital mumbo jumbo here!

I live in a county that borders Tenn in Ga...All the public saftey freqs are vhf conventional...Not trunk...No digital...Plus seeing as how there are lots of tall mountains here an 800 mghz system would be pretty un reliable...To say the least...In my opinion digital trunking in the 700 or 800 mghz range is a big step backwards in reliability...Not to mention the enormous cost involved in erecting untold numbers of repetor towers to make the whole thing even come close to working...I doubt thats ever going to happen around here...If you ask me the idea of 700/800mghz digital trunked systems is as stupid and un effective as the forced digital conversion of local over the air tv...And I bet many agencies go back to conventional systems in the future...
 

MTS2000des

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Cobb County, GA Stadium Crime Zone
I live in a county that borders Tenn in Ga...All the public saftey freqs are vhf conventional...Not trunk...No digital...Plus seeing as how there are lots of tall mountains here an 800 mghz system would be pretty un reliable...To say the least...In my opinion digital trunking in the 700 or 800 mghz range is a big step backwards in reliability...Not to mention the enormous cost involved in erecting untold numbers of repetor towers to make the whole thing even come close to working...I doubt thats ever going to happen around here...If you ask me the idea of 700/800mghz digital trunked systems is as stupid and un effective as the forced digital conversion of local over the air tv...And I bet many agencies go back to conventional systems in the future...
the advent of multiband portables such as the APX, Harris and Thales solve the problem of incompatible operating bands. The cat's meow will be dual band systems, with sites on both VHF and 700/800. Build out of 700/800 in urban areas, with VHF used in rural areas. Not hard. We've been doing this for over 30 years in amateur radio.

Digital trunking does have some major advantages, increased capacity is one. In a major metro area like Metro Atlanta, we'd be taking a huge step back trying to use a conventional analog system. Trunking makes sense for large municipalities.

With the APX product line, and say if some rural sites came online that were VHF, you wouldn't have the issues you are presenting. Plus, with radios like the APX, you still have compatibility with neighboring jurisdictions on legacy conventional analog systems for end user interoperability.

the investment should be made in more capable subscriber units that can operate on multiple bands and systems with minimal user intervention. Just like a cellphone that can switch between cellular, PCS and AWS bands and select an authorized system automatically, the public safety subscriber radio should be able to do the same.

The biggest issue right now is the complexity of these multiband radios. Of course they are relatively in their genesis. I'd say in another 5-10 years refinements in the user interfaces will be made.
 

MTS2000des

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I am real curious on how during this "roll call" someone in Atlanta was able to connect to a system 80-100 miles away on 700/800 MHz! Yes, Cobb can add TG's to their system for the users in other jurisdictions, but those agencies are going to have to program in the Cobb DTRS.
Once ISSI roaming is enabled this will be possible. Good luck, right now all our digital systems are just like the perfectly functioning analog ones we replaced in metro Atlanta: "separate but equal".

The challenge is managing a system like this is who is going to run it. We NEED a true radio authority like Indianapolis/Marion Co, IN MECA in metro Atlanta to get our own area on the same sheet of music before joining the BIG BAND of a state or regional system like the TVRA in GA. What we need is LEADERSHIP like Indiana with Project Hoosier SAFE-T which was a springboard from MECA but that isn't likely to happen.

The GTA is ineffective at managing such a system. The so-called GEWIN project is proof of this. We paid 8 million dollars for a MotoBridge VOIP software package supposedly installed at all E911 centers to bridge radio systems and by the state's own audit it isn't being utilized.

Until then, it's business as usual down here.
 

jim202

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I live in a county that borders Tenn in Ga...All the public saftey freqs are vhf conventional...Not trunk...No digital...Plus seeing as how there are lots of tall mountains here an 800 mghz system would be pretty un reliable...To say the least...In my opinion digital trunking in the 700 or 800 mghz range is a big step backwards in reliability...Not to mention the enormous cost involved in erecting untold numbers of repetor towers to make the whole thing even come close to working...I doubt thats ever going to happen around here...If you ask me the idea of 700/800mghz digital trunked systems is as stupid and un effective as the forced digital conversion of local over the air tv...And I bet many agencies go back to conventional systems in the future...
Your not the only person that has said this and pointewd out the facts of life to these people. problem is they don't seem to care. My bet is the radio company (probably Motorola) has been wining and dining these decision makers to the point they can't see the light through the forest. My bet is also that they don't have a person in the loop that has any radio technical savy to understand just how propagation works and can provide feedback to the project on a reject or accept basis. So all us tax payers tax it in the boot on projects like this. The radio companies walk away saying you got what you ordered. If you wanted more, you should have said something.

Take Virginia, they had the smarts to figure out early on that their STARS trunking system was not the holy grail answer for the state. They have started installing radio gateways in their dispatch centers to link what radio channels they need into the gateways. Then link multiple gatewys together as needed. They now have about 70 gateways up and running under their COMLINC project. They are very happy with it. The COMLINC project has been a very user friendly package, easy to use, very flexible in connecting non compatible radios together. An example was on Wednesday this week, the state police came into Spotslyvania county to cover for the sheriff's personell. They all were attending a funeral for a deputy that died in a boating accident. They tied the dispatch center in Spotslyvania county to the dispatch center in Fairfax. The Fairfax center then patched their gateway into one of talkgroups on the STARS system. Now you have the EDACS system talkgroup in Spotsylvania talking to a Motorola trunking talkgroup like it's a party channel.

The gateway system works real well, cost a whole bunch less that building out a trunking system that the world can get on. Plus explain to me how you would ever be able to have thousands and thousands of individual radio ID's all on a common system? The only way it can happen is to share the user id numbers like the cellular system does and do a roaming software package. Problem with this is that the current ID system has no local designator attached to it to even start to allow for this. Oh by the way, Motorola forgot to tell you that you have to buy all new radios with a different ID system before you can go to the new country wide radio network system. Something about the radios you have now are not able to work on the new system due to the ID software handshake needed. Anyone see the writing on the wall here?
 

radiofan1

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Jim, I saw the writing on the wall over 20 years ao. Motorola is as corrupt as the day is long. Motorola SUCKS. :mad:
 

radiofan1

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SKYNET156, yes the APX7000 portables are shown on the video. The info shown at the "key hand over" indicates a Motorola ASTRO25 Integrated Voice and Data (IV&D) system.

-M142

The price tag on that portable is a rip off of taxpayer money. :roll:
 

AndrewCicotte

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2-shay

Ok, for a big, and I mean BIG FLAT city, digital trunked systems in the 700/800mghz bands make some sence...However, take Cherokee county Ga for example, Has over a 1,000,000 people and so many cops, you'd think half the people that live there must be cops!!!...That said...They allocated freqs in the 800mghz band like 7 or 8 years ago for a new trunked system...To be like there neighbors to the south, Cobb county...But somebody with some radio savy had enough sence to stall the change-over indefinatly because they know the inharint problems ascocieated with 800mghz digital systems...And you know what? As big as Cherokee county is, they dont have a problem with comm trafic...Each city has there own channle and the county has a dedicated trafic channle and several tac channles as well as standard car to car channles..County cops are divided up into group A,B,C,D and E...They may have more now but its been a couple of years since I lived there...Any who, Cherokee county refuses to make the switch..Kudos Cherokee county Ga.!!!...I bet if motorola made scanners as well as comercial radios there would be nothing that could not me monitord!!!
 

b7spectra

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Cobb County, GA
Cherokee County is a bit different. All comms are handled through the Cherokee 911 center. Everyone in Cherokee is also VHF so interoperability is simply a channel click away. At this time, Canton is having RadioOne build them a 3 site LTR VHF system. Granted, they will be LTR and the rest of the county is analog repeater channels, they will be able to have some interoperability as the Canton dispatch is still currently going to be at 911. I have a feeling if this LTR system works and works well (as well as the cost being millions of dollars LESS than what Motherola would have charged), I'm quite sure the County and other jurisdictions may follow suit. It would be a win-win for the county and their tax base, but a lose-lose for us with scanners.
 
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