New AZWINS Sites

[cellphone]

Hi All. I have caught some new site neighbors on the AZWINS System that I am trying to identify location. Post if you can receive these sites:

Site 217 (RFSS 2, Site 17)
774.31875 Control Channel **note this is the same frequency as control channel for South Mountain Site 201
Neighbor of Towers Mountain Site

Site 218 (RFSS 2, Site 18)
770.40625 Control Channel
Neighbor of South Mountain Site

 

[p19997]

Where are you receiving the system you are trying to identify and on what control channel frequency. I am getting 774.31875 in Baja Tempe but that's likely just S. Mountain. I don't get 770.40625 but see that it is used as control channel for about four other known sites.

 

[mesocyclone]

Anyone know what "Neighbor of..." means?

 

[p19997]

Anyone know what "Neighbor of..." means?

P25 sites are somewhat analogous to cell phone sites. For each tower, surrounding sites are identified and defined in advance in the system.

The nominal case is when a radio is in the effective area of coverage of a tower. As long it is there, that tower will service it and the radio will stay tuned to that tower's control channel. As a mobile radio moves in any direction, it will eventually approach the limits of its current site and the signal strength of the received control channel will drop. However, as it approaches a neighboring tower, the received strength of that tower's control channel will increase. At a certain point, the computer controlling the system will hand-off the radio from the original tower to one which now provides the best control channel signal. That way, the radio will not lose communication with the system.

Hope that explains it

 

[cellphone]

Neighbor sites in a P25 system are adjacent sites that are published on the control channel. As a user of the system travels out of range of a site they are affiliated with, this is a list of sites that a radio can affiliate with to maintain seamless communication. It is a similar concept to cellular phones where you travel outside the range of one cell site, and into the range of another cell site.

There are several software packages like Unitrunker, Pro96com, etc that examine control channel data an display information about many attributes of the trunked systems including neighbor sites. It is a great way to discover unknown sites that are in use on the systems. Here is an example from Unitrunker (Unitrunker):



And Pro96Com(Pro96Com - Control channel decoder for P25 Trunked Radio Systems):


Take a look at these software packages if you have not. They provide a TON on data about trunked systems beyond what you can get with a scanner alone. There is a Radio Reference forum Voice/Control Channel Decoding with more info too:

Voice/Control Channel Decoding Software

For discussion of software applications which decode digital voice formats and trunking control channels. Please use the HF Digital Signals forum for anything below 30MHz.

forums.radioreference.com

 

[mesocyclone]

Tks - I wasn't aware of the neighbor publishing. So, "Neighbor of South Mountain" means not at the same site, but a nearby one - a neighboring "cell" - coverage area?

 

[KB7MIB]

Tks - I wasn't aware of the neighbor publishing. So, "Neighbor of South Mountain" means not at the same site, but a nearby one - a neighboring "cell" - coverage area?

A neighbor of South Mountain would be North Mtn/Shaw Butte to the north for example. Perhaps Sacaton Peak to the south, and White Tanks to the west.

John
Peoria

 

[apco25]

Each site P25 control channel constantly updates the adjacent sites via the transmitted data stream to the subscriber radios. This allows the radios to sample RSSI values and determine when if needed to change sites.

 

[AzTac]

Anyone know what "Baja Tempe..." means??

 

[p19997]

"Baja" is Spanish for "Lower", just as Baja California means Lower California. So Baja Tempe is the 85284 zip code of Tempe.

 

[InlandAZ]

I'll have to load up the Casa Grande site, and maybe I can once again hear the new DPS system.

 

[cellphone]

I'll have to load up the Casa Grande site, and maybe I can once again hear the new DPS system.

The Casa Grade site is lower elevation compared to other nearby sites, but you might have good luck with the Casa Grande site in far South Chandler. Your best best would probably be Thompson Peak, South Mountain, or Pinal Peak if you are located in Chandler.

Also keep in mind that not all talkgroups are carried on all sites. If there are not users affiliated to a particular site on a talkgroup, you will not hear much. South Mountain is probably the busiest of those sites often carrying DPS Metro Central, East and South talkgroups.

 

[GlobalNorth]

I'll have to load up the Casa Grande site, and maybe I can once again hear the new DPS system.

You should be able to hear District 6 without any issue.

 

[KB7MIB]

DPS isn't yet patching the UHF channels 24/7/365 to AZWINS. It is more often than not, but it's not quite full time, yet. If you want to be sure to be able to hear DPS, your best bet is to listen to the UHF channels.

Now if you want to hear ADOT, particularly the IRU units, or ADOT Enforcement officers, then yes, you want to listen to AZWINS.

John
Peoria

 

[InlandAZ]

We moved to Maricopa (City) last year, I do see some trunking data on the scanner for the site, but so far no active communications. I'm still plagued somewhat by that cell tower a block away, but in the early mornings before everyone fires up their phones I get a full five bars.

 

[InlandAZ]

Just an update - I had to reload the talk groups, some had changed, but I'm receiving quite well. Most of the hits are from the South Mountain site, which is odd because when we moved to Maricopa last year it was totally deaf.

Sure wish there was more to monitor out here, I miss the Phoenix/Chandler areas. And BTW, I heard MPD on Simulcast C this morning - Someone had posted that they had moved to the new P25 Phase 2 system out here.

 

[caphab1]

Morning All. I found a DPS Document from FCC that had a list of all sites. There is one in Mohave County that is curious. They are calling it Christmas Tree and the coordinates are no where near the city. Anyone have any info?

BTW, @aztec, the Tempe location appears to be on an ASU Tempe building.

 

[KB7MIB]

Christmas Tree Pass is a 16 mile scenic drive near Laughlin, NV. There may be a radio tower site up there.

John
Peoria

 

[caphab1]

John, thank you! The document didn't have pass on there, so that makes sense will hopefully help in reference to the coordinates.

 

[p19997]

Morning All. I found a DPS Document from FCC that had a list of all sites. There is one in Mohave County that is curious. They are calling it Christmas Tree and the coordinates are no where near the city. Anyone have any info?

BTW, @aztec, the Tempe location appears to be on an ASU Tempe building.

Could you please share the subject document? Thanks.