Montana Statewide Interoperable Public Safety Radio System

[dustinoboy]

Does anyone know the base frequencies, offset, and step for the Big Mountain, Desert Mountain, and/or Kalispell transmitters? The banks that are used are not listed in the site comments.
Thanks.

[batwingtech]

Originally Posted by dustinoboy

Does anyone know the base frequencies, offset, and step for the Big Mountain, Desert Mountain, and/or Kalispell transmitters? The banks that are used are not listed in the site comments.
Thanks.

Here are the station TX frequencies for the sites you mentioned.
Desert:

154.6650
155.0250
156.1950
154.1300

Kalispell:

151.3100
153.8750
154.8900
155.7000

Big:

170.8500
154.9425
154.9200
155.9700

[Helitac]

I currently have the Bearcat 300, a 785D and the 996XT. ARC-XT Pro is the software most of my programming is done on. Since Montana is going ahead with the statewide interoperability plan, and there is getting to be more use in the area, I have decided to program the P25 Conventional Repeaters into my 996XT.

As I review the info on RR I note the sytem type is listed as "Project 25 Phase I (FDMA)" which I interpret to mean it is not an exclusive P25 trucking system, rather it can be used as a conventional analog/digital system. However the system voice is labeled as "APCO-25 Common Air Interface Exclusive" which, based on my limited knowledge of the P25 system, means it is a trunking system.

Reviewing frequencies for the repeaters, I also note one TX and one RX frequency for each site. In my mind that makes this a one-frequency set up. Am I wrong in assuming a trunking system needs at least four frequencies for data/voice?

Correct me if my assumptions are wrong, but this brings me to a question. In programing the 996XT should I list the system as "Conventional", "P25 Standard" or "P25 One-frequency trunk". I will also ask if I need to program the repeater sites AND the individual sites in the system which are not labeled as a repreater site (i.e. McDonald Pass)? I'm not a techy, so plain text would be appreciated.

[Jay911]

Project 25 Phase 1 FDMA means an exclusive P25 trunking system. P25 cannot use analog in any way.

Trunk systems can use as few as one frequency (pair - TX/RX) for the entire operation, depending on their design. In a normal multi-channel trunking system, one channel maintains the control channel data constantly 100% of the time (though that channel may "rotate" through different frequencies, as a way of preventing one repeater from wearing out prematurely). On a single channel site, the control channel will be interrupted while the voice traffic goes on, and will then resume operation as a control channel when the voice traffic is done. Generally single frequency sites are only employed in areas where very little radio traffic is going on. Another possibility is that the RadioReference database only knows about one frequency on that site so far. There could be others that nobody has figured out and submitted to RR yet.

As for programming it, if you are talking about the system in this link - Montana Statewide Interoperable Public Safety Radio System Trunking System, Statewide, Montana - Scanner Frequencies - you need to program that as a P25 Standard system. Put in whatever sites are geographically closest to you and/or where you travel. If you're in Missoula, site 16-1017 and 16-1033 are probably of use to you. (Note to MT DB admin - do those site numbers seem right to you? IIRC you can't have site numbers > 99)

Technically speaking, you only need the frequencies in red programmed in to your scanner. The scanner is smart enough to know from that which other frequencies to use. However, on the sites that I mentioned are probably right for you, none of the frequencies are in red. That means nobody knows which one is the control channel (red) and/or alternate control channel(s) (blue). If you figure that out after you program them in to your scanner, submit the data to RR (click on "Submit" on the top of that page right above the "Montana Statewide Interoperable Public Safety Radio System" title) and let everyone else know. (Explanation: the control channel is the one with data noise sounding like a roaring engine constantly. If the control channel "rotates" through multiple frequencies, one should be listed as the red channel and the others should be listed as blue.)

Hope this helps!

[Helitac]

Thanks for the simple explanation, it helps and was greatly appreciated! I programmed the system as P25 Standard and your description of the single frequency set up makes sense. My confusion was the understanding that most trunking systems usually have at least four frequencies.

Although I follow the Montana Statewide Interoperable Public Safety Radio System Trunking System on RR, I usually follow the license to the FCC for verification of GPS. A majority of the sites listed have been assigned frequencies, but not all have been activated (i.e. Missoula/Alberton), hence the control channel and alternate are not colored. The key I have found is RR doesn’t include the GPS until the site is activated (i.e. Desert Mtn).

When you said the P25 system cannot use analog in any way, you confused me because I am programming the P25 Conventional Repeaters into my 996XT. In the literature on the interoperability system it specifically states some state repeater sites will be “a 1 channel P-25 analog/conventional repeater". I believe it has to do with redundancy in the event some units may not yet have digital capabilities. I don’t think that’s a concern for me since the 996XT is capable of receiving digital signals. Like I said before, I’m not a techy so I can be way off base.

[blantonl]

I updated the system entry with a few sites as gathered from the neighboring sites data from the control channels. I also updated some talkgroups as gathered from the great falls thread.

[artsezhi2u]

I'm wondering if anyone has heard any traffic on P25 Missoula (South) 1017 (3F9).

[martidav]

Good day,

I'll be in Helena in a few weeks.

I see that the RR DB has listings for Helena PD in both conventional and the P25 system.

Which system is the primary now days?

Cheers,
Dave

[Jay911]

Are the RFSS/site numbers with RFSS 16 and site 1000+ legitimate? It was my understanding that sites could not be >255.

[jking54]

I'm currently in MN but moving to Bozeman in June and have had my 996XT for about a month now. I see for instance that Highway Patrol has all districts listed for Conventional but 4 listed for trunked, 3,6,7 & 8, what's the situation on this?

[Helitac]

Originally Posted by artsezhi2u

I'm wondering if anyone has heard any traffic on P25 Missoula (South) 1017 (3F9).

Missoula North and South, as well as Alberton to the west have not been activated as of this date. From the Hamilton area, Missoula area traffic is best heard on Lolo Peak site or University.

[asurnin]

Originally Posted by Jay911

Are the RFSS/site numbers with RFSS 16 and site 1000+ legitimate? It was my understanding that sites could not be >255.

To put my two cents in, these are probably unconfirmed site numbers. The system I monitor/update in my home state, all unconfirmed site numbers are some "off" pattern numbering to let people know they are not legitimate. Seems like the database just won't let you leave those blank maybe?

[artsezhi2u]

Thanks for the information, and sorry for the delayed reply.

[Jay911]

I was in the southernmost part of southern Alberta for a while this past week and decided to try picking up any signals from this system while I was there. I got several runs of good decoding on the Analyze mode on my HP1 from 001-018 Mt Royal - I'm going to let PRO96COM chew on the data for a bit (it can take in the decode logs from the HP1 and do some more work with them) and once that's done, I'll post some info here as well as submit it to the DB.

[Jay911]

Here's what I found and it's been submitted.

Site 001-018 Mt Royal has a control channel of 151.43 on LCN 02-0476. Its alt CC/voice channel is 161.9375 on LCN 09-2075 - never seen a system using two different idens on the same site before. Also never seen a system that uses all 16 (well I guess 14 since the first two are 800MHz and 700MHz default plans) idens either. The list on the RRDB page is pretty much up to date as far as I can tell (it's not in the same format as either the HP1 or PRO96COM delivers).

The following sites are shown as neighbors/adjacents to Mt Royal.

001-017 (Divide): CC 151.085, LCN 02-0407
001-019 (HCSO): CC 154.235, LCN 02-1037
001-020 (Antoine Butte): CC 153.980, LCN 02-0986
001-021 (see below): CC 151.295, LCN 02-0449
001-041 (Lewistown): CC 155.07, LCN 02-1204
001-043 (Judith Peak): CC 151.1525, LCN 15-0841

Some of the above CC frequencies are not in the RRDB - this submission will ask to put them in.

I believe that 16-1005 "Havre" is actually HCSO and thus should be removed as a duplicate.

"Saco", WQDL357, in Phillips County, appears to be the best logical choice for 001-021. Between the FCC license (cross-referenced with the broadcast CC from the neighbor data on 001-018), and the documentation mentioned below, I think Saco is 001-021.

There are a whole bunch of useful and interesting maps and documents on Montana's Public Safety Services Bureau website (mt.gov - Montana's Official State Website). I'm not going to share the direct links because they appear to be hashed somehow, but you can access them by going to this page and looking for "Statewide Maps":

mt.gov - Montana's Official State Website

"Trunked Status Map" is the most interesting, as far as I'm concerned, with "Trunked & Mobile Outbound Coverage Map" a close second. They're very informative on learning more about this system.

Last but not least, talkgroup 855 is definitely highway patrol - whichever detachment/troop/division/etc works in the area served by the Mt Royal tower. Possibly someone working Highway 2 between Shelby and Havre?