Monitoring statewide VIPER talkgroups

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jhc1322

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Hi,

I'm wondering how sites work for air medical transport talkgroups where the helicopters travel hundreds of miles to rural hospitals. I guess how "roaming" in general works on trunking radios. For services that span many sites, are they able to talk to people out of range of the current site, what about the range of the radio? Does VIPER have a system of repeaters that allows a message to go across the entire state?

Thanks
 

n4yek

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..... I guess how "roaming" in general works on trunking radios.
Thanks
Let's say a firefighter from Mitchell County with talkgroup ID of 31002 goes to Charlotte which is in Mecklenburg County for a firefighter training session. If he turns his radio on, the Viper System know that his radio wants to monitor his "home" area because of the talkgroup ID that is uses. The Viper system will route all communications from his Home area to the tower he is currently using, no matter where he is in the state.
 
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reconrider8

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The exact reason I love monitoring viper :) but as for med helps the best way I can understand it is when the call goes out somehow the local tower here (being Halifax which is cloest to the hospital) will start relaying all traffic from vident air even before the call goes out. Not exactly sure how that works because I can't hear all the pages for vident going out until he gets in range but I can hear the call going out for Halifax
 

WA4MJF

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Just a guess, but the sites may be linked by the State Microwave System. It seems that the
techs are sometimes talking on an "order wire" circuit when maintaining the sites.

Ronnie
 

msigmon3306

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Let's say a firefighter from Mitchell County with talkgroup ID of 31002 goes to Charlotte which is in Mecklenburg County for a firefighter training session. If he turns his radio on, the Viper System know that his radio wants to monitor his "home" area because of the talkgroup ID that is uses. The Viper system will route all communications from his Home area to the tower he is currently using, no matter where he is in the state.

Except for one small thing.......your "home" talkgroup is limited to the towers in your own county and the towers in the adjacent counties. When the VIPER went P25 our dispatch talkgroup was statewide, just like in the "old days". Within a week however, everything was narrowed down to in-county and adjacent county towers.

After several weeks of radio H&%L during this transition, I finally got to get back on an ambulance for a shift. Went from Hickory to NC Baptist in Winston-Salem. About 10 miles east of I77 my mobile starts flashing "Affiliation Denied" and beeping. Our CCEMS Dispatch TG isn't allowed on towers past this point. Had to turn the radio all the way down till we got back in range on the way back.

Air medical services may be state-wide due to the distances they cover. Us ground-pounders? Not so much.
 

KM4WLV

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I monitor WFUBMC Air Care (aka Baptist Air Care) in Winston Salem, as well as Carolina's Medical Center (CMC) Med Center Air on a daily basis on VIPER since those are the two flight services covering Rowan County. I've got a close friend who lives near the NC coast that used to live here and was on my FD, and the last time CMC was dispatched to Rowan he called me to ask what it was for because he missed part of the call.

This makes me wonder if the talkgroup's used by the ground and air units of these trauma centers are in fact statewide or if there just happened to be someone in his county at the time with a radio parked on the CMC Med Center Air talkgroup, but as Mark said if they're restricted it would seem the TG wouldn't work at the beach since CMC doesn't cover that area.........

In the reprogramming for my 396XT I've made sure to keep WFUBMC, CMC, Vidant, UNC AirCare, etc all in a scan list to see if I can catch them and a location to find out if they are in fact statewide TG's.
 

WA4MJF

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Except for one small thing.......your "home" talkgroup is limited to the towers in your own county and the towers in the adjacent counties. When the VIPER went P25 our dispatch talkgroup was statewide, just like in the "old days". Within a week however, everything was narrowed down to in-county and adjacent county towers.

After several weeks of radio H&%L during this transition, I finally got to get back on an ambulance for a shift. Went from Hickory to NC Baptist in Winston-Salem. About 10 miles east of I77 my mobile starts flashing "Affiliation Denied" and beeping. Our CCEMS Dispatch TG isn't allowed on towers past this point. Had to turn the radio all the way down till we got back in range on the way back.

Air medical services may be state-wide due to the distances they cover. Us ground-pounders? Not so much.
A message went out a while back to turn in a list, by radio ID number, of those
radios that needed Statewide access. I'd guess that your organization missed
it and the helo ambulance companies saw it. Just a guess.

Ronnie
 

msigmon3306

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Nah, most ground ambulances in NC are configured like ours. It makes sense that the air medical ground services would have statewide access since they go all over the state on a regular basis. We have statewide access on the roaming TG's but no one in Catawba is listening to them.

I've tried every way possible to get our units access to just the Clemmons tower so we can stay in contact with Catawba from NCBH....not gonna happen.
 

NathanJ

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In my area, I've heard everything from roaming being TG specific to it's either your county, plus one county in any direction or a specific region, say between I-77 to the west and US-1, to the east.

Of course this is also why the statewide tg's exist. (i.e SW CALL, SW LAW, SW FIRE, etc) along with the VPR Roaming TG's.

NwJ
 

jhc1322

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Thanks for the replies.

To summarize, it sounds like VIPER has microwave or land line connections between sites and a computer system that will route communications to and from distant sites. Radios affiliate with distant sites and "request" to monitor and transmit on a talkgroup just as they would on their home site, with all of the routing happening behind the scenes. Most county-based talkgroups can only affiliate with sites as far as neighboring counties, to prioritize the the routing traffic for services that really need them. Other semi-statewide agencies can affiliate with multiple sites across the areas of the state that they can cover, but not all.

There are a set of statewide TGs that are allocated to county users on a per-incident basis. This is done when a county dispatch official sends an email to VIPER operators.

For rx-only scanners, this must mean there has to be a radio affiliated with the site monitoring the TG for you to receive the traffic since scanners do not affiliate with the site. Using the helicopter example: If the helicopter is nearby, it will affiliate with your site and have all its traffic routed, so you will hear all statewide traffic on that TG. When it flies to the next site, you will no longer hear any traffic on the TG. People who live near the helicopter's dispatch location will always hear all statewide traffic from the helicopter.
 

KE4ZNR

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Thanks for the replies.

To summarize, it sounds like VIPER has microwave or land line connections between sites and a computer system that will route communications to and from distant sites. Radios affiliate with distant sites and "request" to monitor and transmit on a talkgroup just as they would on their home site, with all of the routing happening behind the scenes. Most county-based talkgroups can only affiliate with sites as far as neighboring counties, to prioritize the the routing traffic for services that really need them. Other semi-statewide agencies can affiliate with multiple sites across the areas of the state that they can cover, but not all.

There are a set of statewide TGs that are allocated to county users on a per-incident basis. This is done when a county dispatch official sends an email to VIPER operators.

For rx-only scanners, this must mean there has to be a radio affiliated with the site monitoring the TG for you to receive the traffic since scanners do not affiliate with the site. Using the helicopter example: If the helicopter is nearby, it will affiliate with your site and have all its traffic routed, so you will hear all statewide traffic on that TG. When it flies to the next site, you will no longer hear any traffic on the TG. People who live near the helicopter's dispatch location will always hear all statewide traffic from the helicopter.
This is pretty much spot on....to be fair: are there talkgroups that show up on sites where they probably should not? Of course. As P25 VIPER is tweaked over the next few months you should see that drop somewhat.
The fun part about VIPER is that if you have more than a couple of scanners you can devote one to just finding new VIPER TG activity. I use the Extreme feature set on my Uniden HP-1 to see local VIPER site activity along with my 396XT providing info to Pro96Com on my laptop. I can see all affiliations, talkgroup activity, and neighboring sites info.
Marshall KE4ZNR
 

reconrider8

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i agree with that also but with vident as i said earlier i hear no traffic on the helo tgid until they get dispatched i guess once their tones drop the computer system automatically routes the link to the halifax tower?
 

KM4WLV

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On the note of Med Center Air (Charlotte), and Baptist Air Care (Winston Salem), they always show up on the Salisbury and Faith Mountain sites, whether they are flying locally or statewide. On the note of Baptist Air Care, they have a helo staged / that lives at the Davidson County airport and Davidson County of course borders Rowan County. That could be used to explain the "one county over" concept except the fact that they aren't here in Rowan and their radios don't affiliate with our sites unless they come over. Same thing with Med Center Air out of Charlotte, except their closest helo to us in Mecklenburg County at CMC Main, yet we can hear their dispatches and traffic no matter where the helo's are at, and Mecklenburg County is 2 counties south on I-85.

As far as anyone having a radio parked on those talkgroups here in Rowan full time the only thing I can think of is either Rowan Communications (911), or NCSHP (Salisbury Comm Center). When either of those services fly to Rowan they both have access to our local P25 system and use a TG we call Roamer Dispatch to contact whoever is in control of the LZ to get conditions at the LZ and to get patient updates from EMS.

When we had EMS week here not to long ago both CMC and Baptist flew in to the West End Plaza (formerly the Salisbury Mall) and both crews were carrying XTS25k portables parked on their respective talkgroups on VIPER. I do believe I'll break out Pro96 Com today and play around with it. I can't speak for the rest of the Air/Ground critical services throughout NC but Baptist Air Care is running all the time between the helo and ground trucks. CMC does as well, especially since they've got helo's staged going out to the western side of the state.

Well I think I've rambled enough..........
 
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