Finding DMR Cap+ Sites

[rkillins]

I am monitoring a new DMR CAP+ system. I found the frequency for the one site with DSD+. It has that distinctive pulsing signal on the FMP24 display. DSD+ is reporting a neighbouring site of 3.

How do I find out the frequency of that site (assuming it would have a unique frequency). Would the neighbouring site also have the pulse? Or could it be any frequency? There are other frequencies licensed to the same agency that are carrying transmissions, but since they can be monitored on a traditional scanner, I'm assuming they aren't DMR let alone part of that system. If I wanted to use DSD+ to check whether these frequencies are DMR and part of the system, what configuration would I use to monitor?

Do DMR Sites part of the same same system have any common/shared specifics (lacking the right wording) that can link them to that one system? For instance, do sites of a common system have the same DCC?


SImply looking for a reliable way of searching for new system site frequencies and determining whether such a find is actually part of (a neighbour?) that system.

 

[Whiskey3JMC]

Assuming said system is in Canada, plug in the known frequency(ies) into TAFL search and select province. Examine the results, click "Details" link corresponding to the license you want to examine, then click callsign or "account number" links contained within to divulge other possible frequencies carried via the same location. Hope this helps

Additionally, investing in an RR premium subscription allows you to easily query search the database to see if systems have been documented in the RRDB

 

[rkillins]

Hi Whiskey3JMC, thank you! Yes, aware of the TAFL searches. That is how I found additional frequencies licensed to the user, but I haven't figured out how to determine which frequencies are part of their Cap+ system. For example, one of the frequencies in the query is Site 1 of the CAP+ system. It has the distinctive pulse on FMP and thesystem can be decoded through DSD+. There are two other licensed frequencies that are carrying transmissions, that I believe are simply analogue conventional as they can be heard on a traditional (non DMR capable) scanners. So, unless there is a data field in the TAFL records that ties frequencies to systems, it's difficult.

This is why I was hoping to utilize DSD+ with the frequencies to try and determine what frequencies are part of the system. Knowing there is a site 3 neighbour leaves me believing there is another frequency, but which one right? Will that unknown frequency have a carrier pulse? Can I put in all the licensed frequencies into my frequency file for that system and DSD+ will use them appropriately despite knowing the right site numbers or whether even part of the system?

 

[Whiskey3JMC]

Hi Whiskey3JMC, thank you! Yes, aware of the TAFL searches. That is how I found additional frequencies licensed to the user, but I haven't figured out how to determine which frequencies are part of their Cap+ system. For example, one of the frequencies in the query is Site 1 of the CAP+ system. It has the distinctive pulse on FMP and thesystem can be decoded through DSD+. There are two other licensed frequencies that are carrying transmissions, that I believe are simply analogue conventional as they can be heard on a traditional (non DMR capable) scanners. So, unless there is a data field in the TAFL records that ties frequencies to systems, it's difficult.

No way to determine what's confirmed in use and its mode without listening & observing. I've seldom seen mixed mode usage on CAP+ systems in the USA, though I have seen conventional DMR usage on trunked class licenses. Not sure how things are done up there but it isn't too common here. Just plug them all in conventionally, see if any become rest channels at a later point in time. Then if you have a scanner with LCN finder or an SDR with DSDPlus you can take note of each frequency confirmed in use and gather their channel IDs, which will always be a channel pair, one channel for each TDMA timeslot (Ch ID 1&2, 3&4, 5&6 and so on). The LCN for CAP+ frequencies will be the even number of the channel ID pair divided by 2

 

[CanesFan95]

As you search the bands, consider using an Excel file to log each Cap+ frequency into a row with columns of related information including FCC licensing data like so:



After a while, you can start to piece it all together like a puzzle and figure out numerous systems.