LCN and dsd+

[Ricky2020]

Good morning everyone, first of all, I apologize for any errors, but I'm writing from Italy and using a translator.
We're not fortunate enough to have a site like RadioReference (or equivalent) here, so we have to find the frequencies ourselves.
I'm monitoring a DMR T3 network that serves public rescue.
I detected four control channels belonging to the same network.
Using the LCN Finder function on the Uniden SDS200, I found the four LCNs.
Monitoring one of these frequencies (460.225) in DSD+, without editing the frequencies file, I have attached the screenshot.
How can I find the other network frequencies and voice channels?

 

[Whiskey3JMC]

Welcome to the RR forums. Not sure how radio frequency licensing works in Italy (Ministry of Enterprise and Industry?) but in the USA we have the FCC which regulates radio frequency licensing. I can't locate a website to search licenses under the aforementioned ministry so it may be easier for you to search neighboring frequencies for traffic from the same talkgroup(s) then log which ones are active so you can put the pieces of the puzzle together. Do each of the control channels share the same color code? If color codes are unique then it may make things easier to determine which frequencies are associated with which sites.

Good luck!

 

[mtindor]

Ti prego di fornire degli screenshot della finestra "Event" di DSDPlus mentre sei sintonizzato su quello che ritieni essere un canale di controllo o un canale voce per quel sistema. Includi nello screenshot anche la finestra "Channel Activity".

Ti chiedo inoltre di elencare le frequenze che hai inserito nel tuo scanner Uniden per quel sistema, nonché gli LCN che lo scanner Uniden ha dichiarato di aver rilevato.

Te lo chiedo perché, a seconda della tipologia di sistema T3, l'Uniden potrebbe riportare in modo errato il Network ID, il System ID e il Site ID del sistema stesso. Inoltre, gli scanner Uniden non sempre identificano correttamente gli LCN.

Per quanto riguarda l'individuazione delle frequenze che fanno parte di uno specifico sito trunked — qualora tali informazioni non siano presenti su RR e tu non abbia accesso a un database equivalente a quello della FCC (come invece accade negli Stati Uniti) — è sufficiente scansionare la banda UHF alla ricerca di attività. Quando sei sintonizzato sul canale di controllo e la finestra "Channel Activity" segnala una chiamata di gruppo su un canale specifico, devi cercare rapidamente all'interno della banda un segnale di intensità simile per individuare il/i canale/i voce; questi ultimi, a loro volta, forniranno ulteriori informazioni nella parte inferiore della finestra "Event" di DSDPlus.

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Please provide screenshots of the DSDPlus Event window when you are sitting on what you believe to be a control or voice channel for that system. Also include the Channel Activity window in the screenshot.

Please outline what frequencies in your Uniden for that system as well as the LCNs that the Uniden scanner claimed to find.

I ask because depending upon the type of T3 system, the Uniden will report the system Network ID and System ID and Site ID incorrectly And the Uniden scanners do not always correctly identify the LCNs.

As far as finding frequencies that are part of a particular trunked site, when that information is not on RR and you do not have access to the equivalent of the FCC database like we do in the US, you simply need to search the UHF band for activity. When you are sitting on the control channel and the Channel Activity window says there is a group call on a particular channel, then you need to quickly start looking across the band for a signal of similar strength to find the voice channel(s), which will themselves also provide some information in the bottom of the DSDPlus Event window.

 

[cg]

By using both scanner and DSDPlus, you can figure out the system/site fairly easily.

Monitor the control channel in Passive Digital Monitor mode. Do that by choosing it from the Control tab on the menu.
Program any known frequencies in the scanner and lock out or avoid the active control channel.
Match activity on the DSDPlus screen with the frequency with voice activity on the scanner.
As you match each frequency with LCNs, enter them in the Frequencies file
Looks like you have 2 voice channels so far, 39/40 & 49/50

Unknown Channel number entries:
TIIIStd, H1, 100, ??, 460.2250, 0.0, 0

Unknown Frequency entries:
TIIIStd, H1, 100, 39, ???.????, 0.0, 0

Since the system ID and Site number are not mentioned, I used "H1" as System ID and "100" as site number in my example

 

[mtindor]

By using both scanner and DSDPlus, you can figure out the system/site fairly easily.

Monitor the control channel in Passive Digital Monitor mode. Do that by choosing it from the Control tab on the menu.
Program any known frequencies in the scanner and lock out or avoid the active control channel.
Match activity on the DSDPlus screen with the frequency with voice activity on the scanner.
As you match each frequency with LCNs, enter them in the Frequencies file
Looks like you have 2 voice channels so far, 39/40 & 49/50

Unknown Channel number entries:
TIIIStd, H1, 100, ??, 460.2250, 0.0, 0

Unknown Frequency entries:
TIIIStd, H1, 100, 39, ???.????, 0.0, 0

Since the system ID and Site number are not mentioned, I used "H1" as System ID and "100" as site number in my example

nice example, but that's probably just going to confuse the OP.

Good chance that either 39/40 or 49/50, one of the pairs, will likely be the control channel. Unfortunately, without a voice call on the control channel it's not going to display the CC's LSN. Far more often than not, a T3 CC is used totally for CC functions and is less likely to have voice calls, unlike Con+ / Cap+.

 

[Ubbe]

I detected four control channels belonging to the same network.

How can I find the other network frequencies and voice channels?

For a TIII system that have several sites the control data will include what control channel LCN the other sites are using to be able to have mobile units roam between different sites.

DSD+ will show that in the main window on a bottom row, which site ID that has a LCN for its control channel.

Use the LCN calculator to enter those LCNs and the frequencies of the sites control channels to get the proper bandplan and when a voice channel LCN are displayed in DSD+ you can then enter the LCN into the calculator to get its frequency.

LCN to Frequency calculator for DMR TIII

Seems like a few people are interested in this calculator I mentioned in a post a few days ago. Here it is. This is only for calculating LCNs for DMR TIII. It will not work for CAP+,CAP MAX, CON+ or any other system. This 'DMR_TIII_LCN_Freq_calc' is provided 'as is'. - This is just a basic...

forums.radioreference.com

/Ubbe

 

[mtindor]

For a TIII system that have several sites the control data will include what control channel LCN the other sites are using to be able to have mobile units roam between different sites.

DSD+ will show that in the main window on a bottom row, which site ID that has a LCN for its control channel.

Use the LCN calculator to enter those LCNs and the frequencies of the sites control channels to get the proper bandplan and when a voice channel LCN are displayed in DSD+ you can then enter the LCN into the calculator to get its frequency.

LCN to Frequency calculator for DMR TIII

Seems like a few people are interested in this calculator I mentioned in a post a few days ago. Here it is. This is only for calculating LCNs for DMR TIII. It will not work for CAP+,CAP MAX, CON+ or any other system. This 'DMR_TIII_LCN_Freq_calc' is provided 'as is'. - This is just a basic...

forums.radioreference.com

/Ubbe

Those are pretty low numbers for LCNs. 39/40 = LCN 19 49/50 = LCN 24. Not a typical LCN that you'd see for 460.225 or anything in 460. Yeah there could be a bandplan, but I'd also not rule out the possiblity that they were custom added LCNs by the sysadmin that might not adhere to a bandplan. So that LCN calculator may not be useful.

 

[Ubbe]

So that LCN calculator may not be useful.

There's no real good reason to make your own LCN number system in a DT3 system.

You never get the LCN for the control channel in the site your are monitoring, you only get its voice channels and adjacent sites control channels.

You normally have no problem finding different sites control channel frequencies and DSD+ will show the LCN of adjacent sites so you can match those together and add to the calculator to find out the bandplan and can then map out all channels in the whole system.

/Ubbe