Liberty County 700MHz

[lchspanther2006]

Shouldn't be turned off to add more talkgroups, they don't have to shut down the system to do that. Would guess a maintenance issue or problem, all the more interesting because there are two transmitter sites for Liberty: Over by Airport and and the Coastal Electric Cooperative (they both simulcast on the same frequencies).

Very interesting, looking forward to anything else you hear.

It was interesting to me also that they turned the sites off. When I came back home from Long County, I did not bring my Pro-106, since the system wasnt used, and I looked at my BCD996T, I noticed that there was no site information being displayed. I checked with the Pro-106 and put it to analyze, and there was just static. My brother who is a volunteer firefighter and has a radio issued, turned his on, to find there was no connection to the tower. I am also a volunteer, but I got out for a little while last year and just rejoined with another department, so I have not yet been issued a radio.

Anywho, I will keep this thread updated as I find out more information.

 

[lchspanther2006]

Update March 25, 2012:

The Liberty County 700MHz system was brought back online as of 4:00pm when I checked, however, it not being used by any departments as of this time. It is unknown what was done during the shutdown time.

 

[KB4WG]

System shutdown

The SEGARRN was turned to Site Trunking mode for the purpose of performing some System Wide modifications to the network. The downtime was scheduled and accomplished as planned.

 

[lchspanther2006]

The SEGARRN was turned to Site Trunking mode for the purpose of performing some System Wide modifications to the network. The downtime was scheduled and accomplished as planned.

Thanks for the information. I must ask what exactly is meant by "Site Trunking mode?"

 

[lep]

I monitor site #103 (physically in Bulloch county although there are NO Bulloch agencies on SEGARREN)
I monitor running both a BCD996XT and an HP-1 both under ARC software as 'virtual scanners' and logging.
For the last 24 hours there have NO Liberty county 'hits' on site #103 although Bryan, Effingham and Chatham appear show normal traffic loads. So any service work underway only seems to have been in Liberty, there is no seeming change in traffic on site 103.

 

[KF4LMT]

Site trunking means that the site was operating on its own, not as part of the overall system. It wasn't linked to the Chatham, Bryan, and Bulloch sites during that time. The result is that a radio on the Liberty site would have only been able to talk to radios on the liberty site, not radios on Bryan, Bulloch, or Chatham.

 

[lchspanther2006]

Site trunking means that the site was operating on its own, not as part of the overall system. It wasn't linked to the Chatham, Bryan, and Bulloch sites during that time. The result is that a radio on the Liberty site would have only been able to talk to radios on the liberty site, not radios on Bryan, Bulloch, or Chatham.

Thank you Mac. I do know that when Liberty was taken down, the whole tower was offline. There was no signal whatsoever, and even the radios for the fire department had no connection to the tower, although my brother did state that when he went to Richmond Hill, his radio connected to the Bryan County tower and he stated that he tried it transmit and it did. I was not with him, so I cannot verify if it actually did or not. I know all Liberty Fire units had to switch back to the VHF system until the tower came back online. I have a lot to learn about trunking radio networks.

 

[lep]

Liberty county FIRE dispatch, TG 12806 is again being heard on site #103 in Bulloch county, logged at 2152 hours local.

 

[KB4WG]

Site trunking is a fall back mode of operation in case of loss of system network connectivity. A site or simulcast cell (what we call a subsystem) will go into site trunking if it looses connection to the Master site. The master site is the main computer center for the entire network. In the case of the maintenance event, the entire system was in Site Trunking because the Master Site was taken completely down. In Site Trunking each individual Subsystem or stand alone site remains in full trunking mode and operates normally with the exception of being unable to conduct communication accross the Wide Area Network (WAN). In other words, on a normal day I can communicate on a GSP TG the entire length of I95. A trooper in Brunswick could talk directly to one in Springfield. In Site trunking the trooper in Brunswick could only talk to units under the footprint of the Glynn system and the Trooper in Springfield could only talk to troopers under the footprint of the Effingham subsystem.

Loss of the Master is almost impossible unless we take it down. It is 4X redundant and in most cases has multiple routes to each subsystem.

Hope this answers your question. SEGARRN has a web site with some information about the system at https://segarrn.chathamcounty.org

 

[KF4LMT]

Thanks for the good info and the URL!

 

[lchspanther2006]

Site trunking is a fall back mode of operation in case of loss of system network connectivity. A site or simulcast cell (what we call a subsystem) will go into site trunking if it looses connection to the Master site. The master site is the main computer center for the entire network. In the case of the maintenance event, the entire system was in Site Trunking because the Master Site was taken completely down. In Site Trunking each individual Subsystem or stand alone site remains in full trunking mode and operates normally with the exception of being unable to conduct communication accross the Wide Area Network (WAN). In other words, on a normal day I can communicate on a GSP TG the entire length of I95. A trooper in Brunswick could talk directly to one in Springfield. In Site trunking the trooper in Brunswick could only talk to units under the footprint of the Glynn system and the Trooper in Springfield could only talk to troopers under the footprint of the Effingham subsystem.

Loss of the Master is almost impossible unless we take it down. It is 4X redundant and in most cases has multiple routes to each subsystem.

Hope this answers your question. SEGARRN has a web site with some information about the system at https://segarrn.chathamcounty.org

Thank you for the great information. I must ask however, since I am confused, if the master site was taken down and each site was in site trunking operation, why was the Liberty County tower completely offline? The control channel was there, then it was gone, nothing but static? My brother stated that he could connect to the Bryan County tower with no issue, however I was not with him to confirm. BTW, his radio is issued for Liberty County Fire, if that makes any difference. I hope you can clarify this for me.

 

[KB4WG]

Site Trunking

One of the issues with a site in Site Trunking is that other radios, for instance in Bryan County, may end up on the Liberty subsystem. In that case Bryan users would not hear the radios on the Liberty subsystem. Since Liberty was not totally moved at the time of the maintenance event the decision was made to shut down the Liberty subsystem and move Liberty back to VHF for a short period of time. Doing so minimized the number of Bryan county radios that could get lost on other subsystems and decreased the number of "special" circuits we had to set up to accomodate the downtime.

 

[lchspanther2006]

I have a question. I have my Pro-106 hooked up to UniTrunker to monitor the SEGARRN Liberty County Control Channel. I have noticed since I have had it hooked up, that there is a "Call" to the Target ID of "65535" with no Source ID. Can anyone tell me what is sending out the call on that ID and what the call is? My Uniden 996T in ID Search does not stop on that ID when it UniTrunker shows it sent out a call.

I have attached a screenshot of UniTrunker with the calls highlighted. I apologize about the non-straight highlighter lines, I was highlighting using my Laptops trackpad.

 

[lchspanther2006]

I have a question. I have my Pro-106 hooked up to UniTrunker to monitor the SEGARRN Liberty County Control Channel. I have noticed since I have had it hooked up, that there is a "Call" to the Target ID of "65535" with no Source ID. Can anyone tell me what is sending out the call on that ID and what the call is? My Uniden 996T in ID Search does not stop on that ID when it UniTrunker shows it sent out a call.

I have attached a screenshot of UniTrunker with the calls highlighted. I apologize about the non-straight highlighter lines, I was highlighting using my Laptops trackpad.

Sorry, I just realized that the Source ID is 65536, not 65535. If I am not mistaken, 65536 is outside of the assignable Radio IDs, so if I can relate to networking in any way, shape, or form, I am going to assume that 65536 must be a broadcast to all radios for some reason or another?

 

[Thunderbolt]

The SEGARRN was turned to Site Trunking mode for the purpose of performing some System Wide modifications to the network. The downtime was scheduled and accomplished as planned.

I suspect the system was upgraded to ASTRO 7.11 by Motorola.

73's

Ron

 

[lchspanther2006]

I have been hearing testing being done on TG 12818 and it sounds to me that it is now in use. I am hearing the callsigns of 181 and 136 which I know Hinesville PD uses callsigns in the 1xx range on the VHF. Perhaps they will not be encrypted. It seems to be general discussion between callsigns so, I will post more information as I listen in. It is pretty active at the moment. 4/27/12 @ 0000hrs.

 

[lep]

Sorry, I just realized that the Source ID is 65536, not 65535. If I am not mistaken, 65536 is outside of the assignable Radio IDs, so if I can relate to networking in any way, shape, or form, I am going to assume that 65536 must be a broadcast to all radios for some reason or another?

I don't know what is meant by the "assignable range of the RIDs..." I have been taking RID to be the same as Unit IDS, that is RID=UID as displayed by the 996XT radios (after the firmware update). The UID of Liberty county radios seem to be of 204xxx series and I have heard SEGARRN radios from other counties that have UIDs of 1000xxx.

[I have been using the feature of HP-1 which allows easy entry of UID into scanner with the alpha equivalent, for example (not the real numbers) UID = 18401 is Trooper 444, so on the screen of the HP-1 the next time that trooper transmites the screen shows "GSP444" a label with more meaning to me as the listener] This requires a lot of listening/note taking and does not work well with Agencies that rotate cars/and or radios according to the shift.

Have I misunderstood the meaning of RID (which is likely!) ??

 

[lchspanther2006]

I don't know what is meant by the "assignable range of the RIDs..." I have been taking RID to be the same as Unit IDS, that is RID=UID as displayed by the 996XT radios (after the firmware update). The UID of Liberty county radios seem to be of 204xxx series and I have heard SEGARRN radios from other counties that have UIDs of 1000xxx.

[I have been using the feature of HP-1 which allows easy entry of UID into scanner with the alpha equivalent, for example (not the real numbers) UID = 18401 is Trooper 444, so on the screen of the HP-1 the next time that trooper transmites the screen shows "GSP444" a label with more meaning to me as the listener] This requires a lot of listening/note taking and does not work well with Agencies that rotate cars/and or radios according to the shift.

Have I misunderstood the meaning of RID (which is likely!) ??

I think you are more on the right track as well as me. There can be 65,535 radios as far as what I understand on a system, an each must have it own unique Radio ID (Unit ID) so that the system can track what talkgroup its on and the like. So while they may have Radio or Unit IDs in the 1000xxx range, there can be no more than 65,535 radios on a system. It seems that many areas use a range of IDs for different reasons. It seems that Liberty County is using 204xxx and 205xxx for its Fire Units. My Radio ID is 205015 while my brothers is 204960. I hope this makes sense and I pray that I am understanding the limits of the Motorola Platform.

 

[SCPD]

65536 is not a valid group ID. This fake group ID is used by the program to represent the morse code station identifier. If you click on the site's Info tab, you may also see the FCC callsign. You can edit the fake group's label to say CWID or BSI.

 

[lchspanther2006]

I think you are more on the right track as well as me. There can be 65,535 radios as far as what I understand on a system, an each must have it own unique Radio ID (Unit ID) so that the system can track what talkgroup its on and the like. So while they may have Radio or Unit IDs in the 1000xxx range, there can be no more than 65,535 radios on a system. It seems that many areas use a range of IDs for different reasons. It seems that Liberty County is using 204xxx and 205xxx for its Fire Units. My Radio ID is 205015 while my brothers is 204960. I hope this makes sense and I pray that I am understanding the limits of the Motorola Platform.

EDIT: I misunderstood. There can be 65,535 talkgroups on a system, not radios. I am assuming radios would be unlimited as long as the tower is programmed to allow them to affiliate. I really need more education in TRS's before I make statements and assumed guesses. I will learn one of these days.