TIII dsd fastlane questions

[andY321]

Hello, I'm looking to follow a TIII (MOT) system with one dongle. Ive been reading the DSDPLUS notes on this subject. In the example in the notes I have been unable to figure out what the numbers underlined below represent.

Extract...The records in the DSDPlus.frequencies file also reference site numbers;
for TIII sites, use the same area.site format:

TIII, 13, 1.1, 600, 462.0, 0.0, 0

I see that I should add the frequencies but after looking through the 1r-log file it seems the site I'm monitoring does not give out the frequencies. I'm not sure of the best way to obtain these frequencies.

Any advice appreciated.

 

[cg]

If you look at the beginning of the FREQUENCIES file (and the other DSDPlus data files) you will see the key for the entries to be made
The FREQUENCIES files has this info:
; protocol, networkID, siteNumber, OTAchannelNumber, TXfrequency, RXfrequency, sortOrder
; for TIII, siteNumber format = area.site
; for TDMA (DMR) channels, only one entry (odd or even channel number) per RF channel is required

So the blanks are RX frequency (you can leave at 0.0) and sortOrder (the order the lines are displayed in the channel activity window.

chris

 

[slicerwizard]

I see that I should add the frequencies but after looking through the 1r-log file it seems the site I'm monitoring does not give out the frequencies. I'm not sure of the best way to obtain these frequencies.

Use licensing data to point you in the right direction. Use a second receiver (scanner, dongle, ...) to find matching voice traffic (same talkgroup ID) when the TIII control channel indicates that a call is active.

 

[andY321]

If you look at the beginning of the FREQUENCIES file (and the other DSDPlus data files) you will see the key for the entries to be made
The FREQUENCIES files has this info:
; protocol, networkID, siteNumber, OTAchannelNumber, TXfrequency, RXfrequency, sortOrder
; for TIII, siteNumber format = area.site
; for TDMA (DMR) channels, only one entry (odd or even channel number) per RF channel is required

So the blanks are RX frequency (you can leave at 0.0) and sortOrder (the order the lines are displayed in the channel activity window.

chris

Thank you very much.

 

[andY321]

Use licensing data to point you in the right direction. Use a second receiver (scanner, dongle, ...) to find matching voice traffic (same talkgroup ID) when the TIII control channel indicates that a call is active.

Thanks. I only have one dongle but I may be able to tune to it quickly if I see it in the spectrum. I also use WTR browser so might be able to get more freq info there.

 

[TheButcher]

You also need to populate 'DSDPlus.networks' and 'DSDPlus.sites' files...


One can discover 'other' frequencies by monitoring with say, SDR# and wait / watch. When voice traffic is active not on the CC (ie. on another frequency) one will see it pop up on the spectrum.



Also look here and DL the little helper (Thanks Mr. thewraith2008)...

LCN to Frequency calculator for DMR TIII

Calculations would be based on RF channels, not DSD+ LSNs. Step size would be 12.5 kHz (RF channels are 12.5 kHz apart) Some scanners don't trunk track DMR, so they need no LCNs, just frequencies. I'm using LCN here as a unique number for each frequency (RF channel) used. So do the trunking...

forums.radioreference.com

Those channel numbers produced by monitoring the CC can be useful! Good luck.

 

[TheButcher]

"have been unable to figure out what the numbers underlined below represent."

Explanation is in the 'DSDPlus.frequencies' file, at the top. Same goes for the other 2 files I pointed out above...

0.0 is just the mobile tx frequency. Not required. It is normally about +- 5MHz away from the 1st frequency...

 

[cg]

It is not necessary to have a valid frequency there but I believe the 0.0 needs to be there if you don't. If not, the SortOrder would be seen as the RXFrequency.

0.0 is just the mobile tx frequency. Not required. It is normally about +- 5MHz away from the 1st frequency...

 

[andY321]

You also need to populate 'DSDPlus.networks' and 'DSDPlus.sites' files...


One can discover 'other' frequencies by monitoring with say, SDR# and wait / watch. When voice traffic is active not on the CC (ie. on another frequency) one will see it pop up on the spectrum.



Also look here and DL the little helper (Thanks Mr. thewraith2008)...

LCN to Frequency calculator for DMR TIII

Calculations would be based on RF channels, not DSD+ LSNs. Step size would be 12.5 kHz (RF channels are 12.5 kHz apart) Some scanners don't trunk track DMR, so they need no LCNs, just frequencies. I'm using LCN here as a unique number for each frequency (RF channel) used. So do the trunking...

forums.radioreference.com

Those channel numbers produced by monitoring the CC can be useful! Good luck.

Thanks for this. I have collected all my cc=numbers from the dsd+ 1r event log. I am considering cc= to represent channel numbers in this instance and not control channel.
In the dsd+channel activity window I see the channel numbers popping up. I am assuming that the key to using this software is taking a channel number at the moment it appears in the activity then clicking on the call in the spectrum and taking note of the frequency. With the known channel number and frequency i can then use the software to calculate the frequencies for the other channels? Only other variable then is the channel spacing which is likey to be 12.5. Am I on the right track here?

 

[cg]

If the channel numbers are based on a calculation yes. You might see something like 325, 461, 1125, etc. However, if you see 3, 7, 15, the odds are it is a list drawn up by the system administrator and is essentially random. You then have to monitor and match channel activity with active frequencies.
If it is a set bandplan and the system is not transmitting that information (like yours), you can calculate the base and step. I have a system that has 461.0500 as channel 884. If I try a 12.5 KHz step first, 884 x .0125 = 11.05 then 461.0500-11.05=450.0000 so that it the base. Once I get that, I put them into a spreadsheet to calculate the other values (unless it is a small system that I can do by hand).

chris

 

[andY321]

Thanks Chris. Im going to need some time to get my head around this. Does the base always relate to the lowest channel number and frequency?

 

[cg]

Base frequency is where you start counting (usually channel 0 or 1). However, sometimes there will be a jump to bypass certain ranges or to change the step. If the program doesn't detect the bandplan being transmitted, DSDPlus relies on the Frequency file where you have matched up the Channel number and frequency. P25 system may transmit the bandplan and you only program the Control channel.
I prefer setting it up in Excel and having the channels calculated then check the license or otherwise search for active frequenciess and try to match them with channel numbers

chris

 

[TheButcher]

Here in NZ we have an online database run by the government / ministry, keeping track of frequencies / licenses etc. Hint: This is very handy! Also, the frequencies are given (allocated) a number. With this in mind, (I think it goes), subtract 1 and then divide by 2. This gets the channel number in the database, or was it, it gives the channel number in DSD+ (one or the other, can't recall).

There should be a pattern and not knowing where you guys are, it is hard to say, but local govt. should have some form of database where you guys are... It is public information (and VERY handy!)...

 

[andY321]

Thanks. Ofcom here in the uk and I also use Wtr browser. I will check them.