P2 Freqs not listed for Lubbock

I discovered 2 frequencies on the Phase 2 system that is not listed in the database, but being used. I havent had time to see if there are more. They are 857.4875 and 858.4875.I believe there may be more since there are about 18 frequencies licensed and not listed in the database for Phase 2 ,( including the old EDACS frequencies).

I'm also trying to see if 856.5375 was listed wrong in the old EDACS system. The license is showing 856.5875. I haven't heard any transmissions on either frequencies yet so I havent confirmed which one is correct.

Also are the MDTs using the cell phone band. I know at one time the MDTs were on a dedicated licensed frequency .

Did anyone catch the shot front of the radio on the Codes Dept on the tv news showing "CODES 1" Thursday night. I think that the database has CODES 1 listed as TG 20116 . This maybe wrong and should be COVERT 1 instead and the correct TG for CODES 1 is yet to be discovered.

Both those are out at Site 3. Back in late February (or early March) I created a post about the two new sites being advertised by the main system. One site represents Buffalo/Ransom and the other Idalou (without taking a Spec-An out there I couldn't tell you which is which). Databases have not yet been updated as I no longer live in Lubbock and was simply on business out there and I'm not expecting others to do the work to really map the new sites.

Mapping

MCore25 said:

Both those are out at Site 3. Back in late February (or early March) I created a post about the two new sites being advertised by the main system. One site represents Buffalo/Ransom and the other Idalou (without taking a Spec-An out there I couldn't tell you which is which). Databases have not yet been updated as I no longer live in Lubbock and was simply on business out there and I'm not expecting others to do the work to really map the new sites.

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Without sophisticated equipment, how does one map the new sites in Lubbock or other locations. I believe you already are aware of my amateur knowledge of radio systems. But, give it a go and I will try to follow.

Ensnared said:

Without sophisticated equipment, how does one map the new sites in Lubbock or other locations. I believe you already are aware of my amateur knowledge of radio systems. But, give it a go and I will try to follow.

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You could use an SDR with a directional antenna and triangulate the sites. We used to have all sorts fun out there doing that with a 433 MHz transmitter. Out in Idalou and Ransom, its less populated (structurally) and flat so it's fairly easy to do. Once you find the signal peaks, you know that is your general heading. After that once can simply drive around and monitor the control channel and see how it does.

Now with a calibrated unit, such as a SpecAn, you can get exact receive signal strengths and go from there. Making an educated guess or two, most P25 systems in the US run 100W out of transmitters and you can use an adjacent site license to guess ERP, you can actually triangulate using an omnidirectional antenna and a map in many cases.

In the Lubbock system's case, those frequencies are reused from the EDACS system and are operating under STA's (which doesn't have to have an exact location) until they get around to modifying the existing licensing. So until that happens, the only real option is to go around and search for which control channel represents which site.

In order to better understand what you are saying, I need an example. When you talk about "modifying the existing license" does this mean that the system is finalized? When I have attempted to look at the Bell County P25 installation, for instance, I see no system ID on my 436HP like I do when I look at Waco P25. I am working on SDR, but I am not there yet.

Ensnared said:

In order to better understand what you are saying, I need an example. When you talk about "modifying the existing license" does this mean that the system is finalized? When I have attempted to look at the Bell County P25 installation, for instance, I see no system ID on my 436HP like I do when I look at Waco P25. I am working on SDR, but I am not there yet.

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Not quite. Bell county is fully operational. P25 doesn’t work unless the system is broadcasting a SID, WACN and has a band plan defined.

By modifying the license, I mean modifying the license location that the FCC keeps on file. It’ll provide things such as the site location, ERP, etc. In many instances, the timeline to get the system operational is shorter than what it takes the FCC to actually modify a license so it’s common to see a STA filed (a temporary license essentially) that basically would let the license place the station anywhere in the defined area.


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