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Old 07-08-2008, 2:34 PM
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Default Question about Open Sky

Our County (Newton Co. Ga) is a few days away from turning on a new Open Sky system, we have been told by our supervisors that in meetings about the upcoming transition to the Open Sky they were told that we will not be allowed to scan, for instance one of the Municipal Police Depts will not be able to monitor say the Sheriffs Dept etc, if they want to listen to them they would actually have to come off their dispatch channel and switch to the Sheriffs Channel, we were told because the way the system is designed too many people scanning will tie up talk paths and make system perform poorly or lose capacity. We were told well you dont need to be scanning any way,! But the end users disagree, we feel listening to other agencies is how you coordinate and work together. If this is the case its a shame that were spending this much money on a new supposedly state of the art radio system and we cant scan other local agencies.

Anybody know about the scan issue?
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Old 07-08-2008, 7:32 PM
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Scanning in a radio on an standard EDACS System is no different than scanning on an Open Sky System. The radio doesn't care and neither does the system. Scanning is done in the radio and has absolutely nothing to do with the backbone itself. They are feeding yuo a line of bull. When a user talks, the system re-transmits and sends it to the radio. Each radio that scans, listens to the Control Channel and does not utilize any additional talk paths just to listen. If this were the case, a system would be pretty much dead in the water just from a regular Radio Shack scanner listening.

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Originally Posted by jrm5265 View Post
Our County (Newton Co. Ga) is a few days away from turning on a new Open Sky system, we have been told by our supervisors that in meetings about the upcoming transition to the Open Sky they were told that we will not be allowed to scan, for instance one of the Municipal Police Depts will not be able to monitor say the Sheriffs Dept etc, if they want to listen to them they would actually have to come off their dispatch channel and switch to the Sheriffs Channel, we were told because the way the system is designed too many people scanning will tie up talk paths and make system perform poorly or lose capacity. We were told well you dont need to be scanning any way,! But the end users disagree, we feel listening to other agencies is how you coordinate and work together. If this is the case its a shame that were spending this much money on a new supposedly state of the art radio system and we cant scan other local agencies.

Anybody know about the scan issue?
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Old 07-08-2008, 9:31 PM
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That's not entirely true. On an EDACS single site system you can scan any talk groups you want. In a multi-site system talk groups can be set to be valid on one or more systems. So you may only here some talk groups if you are monitoring one system while the agency being scanned is on another system. Further, multi-site systems may not have the talk group valid on more than one system until a radio logs in on that talk group on the system

Unlike EDACS, Opensky will steer the out bound traffic only to the repeaters that have units for that talk group logged in. In order to scan on Opensky, your radio tells the system what talk groups are in your scan list and if there are no radios working on the repeater site you are on the system will open up a channel to pass the audio just so you can scan. A few radios scattered about the county scanning a few different groups can tie up resources.
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Old 07-16-2008, 2:14 PM
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Default Utilizing scanning in an OpenSky system

Enabling scanning can potentially tie-up talk path resources within the OpenSky architecture. M/A-Com training materials list these scanning attributes:
1. Scanning is defined as listening to other talkgroups within the current profile.
2. Scanning should not be used for mission critical communications.
3. Scanning may create additional traffic.
4. You will only scan a talkgroup if someone in the same site footprint has that talkgroup selected.

Due to these features, I am also disabling scanning. I can't risk tieing-up talk path resources.
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Old 07-16-2008, 4:31 PM
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Kinda contradicts some of M/A-Com's "interoperability" claims, doesn't it? People on the same OpenSky system cannot even listen to each other? Ridiculous. Not even "operable" for day-to-day public safety communications, let alone interoperable.
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Old 07-16-2008, 7:24 PM
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Originally Posted by DaveNF2G View Post
Kinda contradicts some of M/A-Com's "interoperability" claims, doesn't it? People on the same OpenSky system cannot even listen to each other? Ridiculous. Not even "operable" for day-to-day public safety communications, let alone interoperable.
I second that, Dave. Talk about a serious blow to day-to-day interoperability.

With that scan issue in mind it sounds like perhaps OpenSky wasn't really designed for public safety use, and yet another reason not to buy such a beast.
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Old 07-16-2008, 8:21 PM
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Don't listen to the salseman. Interoperability is not a technology issue. Interoperability is a policy, procedure and training issue. I don't care how much grant money our federal, state and local agencies waste buying very expensive techno gadgets that let them speak to anyone and everyone. When the fit hits the shan, nothing works and nobody knows what to do with it. I have helped agencies spec out equipment to be purchased on these "homeland security" grants. When I ask how they plan to use it in order to guide them in the right direction, I always get the same answer, "I don't know."

The best I have seen was a county that has a nuclear power station. The NRC requires everybody to come together once a year a drill. State, county and cities, law, fire, health, public works, parks. They even drag in the administration and the ARES/RACES. They are graded and critiqued. It works. They also do it on VHF and UHF conventional analog and don't see the need for trunking, 800 MHz or digital voice.
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Old 07-17-2008, 6:33 PM
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Quote:
Originally Posted by DaveNF2G View Post
Kinda contradicts some of M/A-Com's "interoperability" claims, doesn't it? People on the same OpenSky system cannot even listen to each other? Ridiculous. Not even "operable" for day-to-day public safety communications, let alone interoperable.
If a person would put a little thought in to the subject of scanning in a wide area trunked communication system, I think at it would become apparent that all systems have the same issues with channel resource allocation. Scanning uses talk paths regardless of who made the system. I work with a statewide SmartZone system and when new users are trained, scanning is strongly discouraged for several reasons. The state limits the groups in each agency's radios to only theirs and mutual aid groups. If Troopers want to communicate with a sheriff deputy, they must meet half way on mutual aid. This helps to keep the the wide area network from behaving like a poorly designed 5 channel simulcast system.

Back on topic: OpenSkys TDMA format of splitting wide band channels into 2 or 4 time slots would allow more talk paths at each site, so maybe capacity will be great enough for the system admin folks to ease up on scanning a bit in the future. It is less painful to add than take away functions.

73's
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Old 07-18-2008, 6:32 AM
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Scanning uses talk paths regardless of who made the system.
But only OpenSky must create a talkpath using additional system resources when a user puts their radio into SCAN mode. On any other kind of trunking, the system itself is not affected one whit by how many users are scanning it.
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Old 07-19-2008, 7:08 AM
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incorrect, the exact same thing can occur on multi site, wide area smartzone systems (non simulcast)
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Old 07-19-2008, 10:35 AM
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For a SmartZone system, an extra talkpath does not come into existence unless a radio affiliates to a talkgroup on a "new" tower where no other units from that group have transmitted yet.

Placing an OpenSky radio into Scan mode would be equivalent to sending an affiliation or a channel request on another type of system. Scan mode alone is transparent to SmartZone et al.
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Old 07-19-2008, 1:27 PM
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I have some open sky training, but not enough to know how scan fully works. ie does the radio tell the system which GID's are being scanned, etc. What I can tell you is on a muti-site edacs system the radio does not indicate to the system the GID's in the scan list. So having a deputy on the north multi-site listening to north p.d. is not an issue, because they are both logged into the system and both GID's are active on that tower. However if the same north deputy is scanning p.d. south he will never hear the p.d. traffic because a south p.d. unit is not logged iinto the north tower, so no extra site traffic is created. The deputy would have to drag that GID north by changing to that group to as if to talk on it.

So scanning on an EDACS system is not an issue. You can not create more site traffic by scanning.
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Old 07-20-2008, 3:23 PM
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Default well

Thanks for all the info, all I know is that we (county/city) is spending $4.5million dollars and we cant scan other users needless to say end users are dissapointed. We're supposed to have our units in had July 29th, about a year passed original date. Its my understanding MA/COM was still working on glitches the other day, so with 9 days to go and Im not sure all aour portables are in yet. I still think the PD cars and SO cars should have a small underdash 25-30 watt VHF mobile in there with 154.905 and 155.475....to me that would be the simplest fix for the while thing anyway ask everybody to put a $300 VHF underdahs mobile in police cars and load them with some inerop channels and then it doesnt matter what they dispatch on, anybody agree with that ? or is that too simple............
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Old 07-20-2008, 9:25 PM
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What you really need to do is find away to get away from OpenSky without losing your shirts and get a proven system that really works.
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Old 07-21-2008, 8:51 AM
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Run as far away from Open Sky as you can!!! I'm serious!! Get out while you still can!! That's why my County I live in (Lancaster County PA) got rid of the system earlier this year! Our system was more than three years behind schedule and coverage sucked, even with the vehicle extenders......

You can read about the horrors my county had on one of our local message boards. This system is not safe at all! Wanna know what happens when multiple units try to key up and speak at once? Silence!!!

I am repeating this warning! Do not get anywhere near Open Sky!!
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Old 07-24-2008, 1:29 PM
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Talking Open Sky

Open Sky just seems like a big waste of money because it doesnt seem to be prefected enough to work at peak performance, i live in Gallatin Tennessee and we do not have any Open Sky systems in the state at all. I have asked people that deal with the radios in our state and they said if they upgrade to any new radio sysyem it would be an EDACS Standard system. They say Open Sky is a poorly operating radio system because of all the malfunctiobns that are possible of happening. Therefore our state hasn't even thoght about buying ANY Open Sky systems. Gallatin uses 460.475 conventional analog systen and has been using it before I was born which was 1991. I own a Pro 96 so i can listen to trunked systems that sourround us such as Nashville Metro Police which use a Motorola type II smartzone omnilink with APCO 25 common air interface digital voice. They have said they all tried the open sky system in PA. and said their system works a lot better then PA.'s open sky.
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Old 07-27-2008, 8:53 AM
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Dave T Stark said -

For a SmartZone system, an extra talkpath does not come into existence unless a radio affiliates to a talkgroup on a "new" tower where no other units from that group have transmitted yet.

Placing an OpenSky radio into Scan mode would be equivalent to sending an affiliation or a channel request on another type of system. Scan mode alone is transparent to SmartZone et al.

--------------------------------------------------

Dave - I think that if a State Police unit in eastern Massachusetts wanted to scan a western Massachusetts talkgroup, the system would not allow it. If the system did allow it, then a extra talkpath would be created. Therefore, I dont see how a Motorola system is any better than the OpenSky systems in this matter. Peter Sz
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Old 07-28-2008, 11:57 AM
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Quote:
Originally Posted by zerg901 View Post
Dave T Stark said -

For a SmartZone system, an extra talkpath does not come into existence unless a radio affiliates to a talkgroup on a "new" tower where no other units from that group have transmitted yet.

Placing an OpenSky radio into Scan mode would be equivalent to sending an affiliation or a channel request on another type of system. Scan mode alone is transparent to SmartZone et al.

--------------------------------------------------

Dave - I think that if a State Police unit in eastern Massachusetts wanted to scan a western Massachusetts talkgroup, the system would not allow it. If the system did allow it, then a extra talkpath would be created. Therefore, I dont see how a Motorola system is any better than the OpenSky systems in this matter. Peter Sz
I guess I should have said that Scan mode is transparent after the first unit affiliates via the site. Additional units scanning that talkgroup will be able to hear traffic because at least one unit using that site is affiliated to the talkgroup, but no additional talk paths will need to be created.

With OpenSky, every radio needs a talkpath, even if it isn't talking.
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Old 07-28-2008, 1:21 PM
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Quote:
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Interoperability is not a technology issue. Interoperability is a policy, procedure and training issue.
I must respectfully disagree, in part.

While you are quite correct in that interoperability is a policy, procedure and training issue, it's also very much a technology issue. There are many aspects to interoperability, and basic interoperability at the local level includes Agency A being able to monitor what Agency B next door is doing, and responding appropriately, or being ready to respond appropriately, as determined by local protocol. it isn't just being able to talk to each other on a disaster scene and knowing how to do it.

If Agency A can monitor Agency B and know that B is chasing a bank robber into A's jurisdiction, they might be able to be in position well in advance and help catch the evildoer. Without the capability to monitor, B would have to call A on the phone or mutual aid radio, with all the delays and potential errors inherent in having to relay the information multiple times to multiple agencies.
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Old 07-29-2008, 7:51 PM
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Dave Stark - thanks for your reply. I dont understand why Open Sky works that way, but there are many things I dont understand in this world. Peter Sz
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