Johnston County P25 channel update
After lots of monitoring and logging, here is what I have found. Yes, the new P25 is basically using the old site frequencies with some minor changes, mostly in how the sites identify themselves (for instance, I believe Clayton site used to be Site 1 in EDACS, and is now Site 3, and all the others shuffled down in numbering as well). Below is how they are identifying themselves now, at least in Unitrunker.
Important note: The control channels have been changing quite a bit, so the only way I can get this config to work reliably is to enter ALL the channels on each site as control channels and chase it around. What I can't tell you is whether that is standard operation procedure for Harris systems, or if eventually they'll settle down and just designate one as control and one or two more as alternates. Right now it is floating around, maybe they are trying to do some testing to see which frequencies perform best as control channels, I don't know.
I have listed the CURRENT control channel as (c) and all the others as alternates (a) for the reason I mentioned above.
Also, in the list below, I do not necessarily know the LCN order (though I can see the LCN in Unitrunker), so they are just listed here, not necessarily in the correct order for each site. Since P25 system tables self-populate (control channel continually tells the channels in the site), I don't think it really matters.
Site 3 - Clayton
853.9875a
856.7125c
857.7125a
858.1375a
858.7125a
859.7125a
Site 4 - Selma
851.2250c
851.7250a
852.2000a
852.3250a
852.7000a
853.2250a
855.7125a
Site 5 - Archer Lodge
851.4375c
852.3250a
852.9375a
853.7250a
Site 6 - Benson
851.3000c
852.3000a
852.8000a
853.5500a
853.9500a
Site 7 - McGee Crossroads
854.7375c
856.5625a
857.5625a
858.5625a
859.0375a
For those running Unitrunker, you will see the channels listed twice, once as their P25 Phase I slot, and two more times below as their P25 Phase II slots. For instance, Unitrunker identifies Clayton (Site 3) frequency 853.98750 as LCN 00-0234 (Phase I) and again two more times as Phase II slots as 08-0468 (slot 1) and 08-0469 (slot 2). That is, LCNs with a 00 prefix are the Phase I channel identifiers, and those with prefix 08 are the Phase II channel identifiers.
A review of the logging shows fairly well distributed hits on the Phase I traffic and the Phase II traffic, for the example frequency above, there were 3100 Phase I traffic hits, and 3141 / 341 Phase II hits slots 1 / 2. Regarding Phase II traffic, there is a weighting toward using the first slot in the channel timing over the second slot, about 2:1, which means little and it probably driven by Harris' algorithm. (It's also possible that Phase I hits also count toward Phase II slot 1 hits, I don't know).
Having designed a system or two in my younger days, I'd have to say the system is working well from a performance standpoint (I can't speak to what the users think of it). It really got a workout on the day with the three bad wrecks on I-95 a few weeks ago, soon after switching over to the P25 system. The Channel Activity display in Unitrunker looked like the Amtrak arrival board in Penn Station, every channel seemed to get a workout, though there seemed to be no problems. Kudos to the radio folks.
After lots of monitoring and logging, here is what I have found. Yes, the new P25 is basically using the old site frequencies with some minor changes, mostly in how the sites identify themselves (for instance, I believe Clayton site used to be Site 1 in EDACS, and is now Site 3, and all the others shuffled down in numbering as well). Below is how they are identifying themselves now, at least in Unitrunker.
Important note: The control channels have been changing quite a bit, so the only way I can get this config to work reliably is to enter ALL the channels on each site as control channels and chase it around. What I can't tell you is whether that is standard operation procedure for Harris systems, or if eventually they'll settle down and just designate one as control and one or two more as alternates. Right now it is floating around, maybe they are trying to do some testing to see which frequencies perform best as control channels, I don't know.
I have listed the CURRENT control channel as (c) and all the others as alternates (a) for the reason I mentioned above.
Also, in the list below, I do not necessarily know the LCN order (though I can see the LCN in Unitrunker), so they are just listed here, not necessarily in the correct order for each site. Since P25 system tables self-populate (control channel continually tells the channels in the site), I don't think it really matters.
Site 3 - Clayton
853.9875a
856.7125c
857.7125a
858.1375a
858.7125a
859.7125a
Site 4 - Selma
851.2250c
851.7250a
852.2000a
852.3250a
852.7000a
853.2250a
855.7125a
Site 5 - Archer Lodge
851.4375c
852.3250a
852.9375a
853.7250a
Site 6 - Benson
851.3000c
852.3000a
852.8000a
853.5500a
853.9500a
Site 7 - McGee Crossroads
854.7375c
856.5625a
857.5625a
858.5625a
859.0375a
For those running Unitrunker, you will see the channels listed twice, once as their P25 Phase I slot, and two more times below as their P25 Phase II slots. For instance, Unitrunker identifies Clayton (Site 3) frequency 853.98750 as LCN 00-0234 (Phase I) and again two more times as Phase II slots as 08-0468 (slot 1) and 08-0469 (slot 2). That is, LCNs with a 00 prefix are the Phase I channel identifiers, and those with prefix 08 are the Phase II channel identifiers.
A review of the logging shows fairly well distributed hits on the Phase I traffic and the Phase II traffic, for the example frequency above, there were 3100 Phase I traffic hits, and 3141 / 341 Phase II hits slots 1 / 2. Regarding Phase II traffic, there is a weighting toward using the first slot in the channel timing over the second slot, about 2:1, which means little and it probably driven by Harris' algorithm. (It's also possible that Phase I hits also count toward Phase II slot 1 hits, I don't know).
Having designed a system or two in my younger days, I'd have to say the system is working well from a performance standpoint (I can't speak to what the users think of it). It really got a workout on the day with the three bad wrecks on I-95 a few weeks ago, soon after switching over to the P25 system. The Channel Activity display in Unitrunker looked like the Amtrak arrival board in Penn Station, every channel seemed to get a workout, though there seemed to be no problems. Kudos to the radio folks.
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