LCN to Frequency calculator for DMR TIII

thewraith2008 · Oct 3, 2019

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 program and may not be perfect. I made this a few years back.
- I have no plans to evolve this further.

Should work in Windows 7 and 10 without extra dependencies.

You still need to work out the reference LCN + frequency for this to work right.

Pressing 'Enter' after entering a value for each field will move to next field or to button if last field. Red means field value is bad.

You can sometimes work out a CC LCN by looking at a 'Neighbor' sites neighbor list.
Or just observing when a traffic channel (frequency) is active (in FMPx) and what DSDPlus says the LCN is.

As usual, please read any documentation supplied.
Any questions, ask away.
Hope it works for you.

Download

HASH: c604e2bbc5739801429effec982b4f70

Ubbe · Oct 4, 2019

Just for clarification: It's for LSN, Logical Slot Numbers that DSD uses, one number for each time slot, and not LCN Logical Channel Numbers, one number for each frequency, that Uniden uses.

/Ubbe

thewraith2008 · Oct 4, 2019

Ubbe said:
Just for clarification: It's for LSN, Logical Slot Numbers that DSD uses, one number for each time slot, and not LCN Logical Channel Numbers, one number for each frequency, that Uniden uses.

/Ubbe

While I didn't devise the nomenclature for DSDPlus or DMR TIII, and I'm not saying it's right or wrong, this is how it's use:
In the context of DSDPlus, it's LCN (Logical channel number) that is used.
In the DMR standards (TS 102-361-04) , LCN (Logical channel number) is also used.

In DSDPlus it refers to slot1 and slot2 having different LCNs to differentiate each slot.

In the standards it refers the the frequency (having both slot1 and slot2) been the LCN. see quote below.

from the standards (TS 102-361-04) said:
4.7.1 Radio Frequency Allocation
The Tier III protocol supports a number of different physical channel strategies to accommodate operation in radio
channels that may be dedicated, in blocks or re-farmed.
Physical radio channels may be specified by either:
a) a logical channel plan whereby a transmitter and receiver frequency is mapped to a logical channel number.
The Tier III protocol permits up to 4 094 such logical/physical relationships; and/or
b) a mechanism whereby the absolute transmitter and receiver frequencies are specified in the PDUs that are
passed between BS and MS at the air interface.

The standards say slot1 is TDMA channel 1
The standards say slot2 is TDMA channel 2

above image from the standards (TS 102-361-04) said:
as seen in:
- Table 7.9: Private Voice Channel Grant PDU content
- Table 7.10: Duplex Private Voice Channel Grant PDU content
- Table 7.11: Talkgroup Voice Channel Grant PDU content
- Table 7.12: Broadcast Talkgroup Voice Channel Grant PDU content
- Table 7.13: Private Data Channel Grant PDU content
- Table 7.14: Duplex Private Data Channel Grant PDU content
- Table 7.15: Talkgroup Data Channel Grant PDU content

Neither DSDPlus or the standards make reference to LSN or Logical slot number

Ubbe · Oct 4, 2019

I stand corrected. It was Uniden themselves that came up with LSN, when they instead should have called their number plan for LFC, logical frequency numbers.

I had one issue that the control channel in the systems I monitor are always on slot 2 and the voice channels on each voice frequency always begins with slot 1 and when a second conversation are started it uses slot 2. So the control channel are always an even LCN number and when an unknown voice channel starts it's always an odd LCN number and when using the calculator it shows a frequency that's 6,25Khz too low if the voice frequency are higher than the control channels, and 6,25Khz too high if the voice frequency are below the one for the control channel at that site.

Could the formula be modified to concider the 6,25KHz error so that the result are always a valid frequency?

/Ubbe

thewraith2008 · Oct 4, 2019

Just a small fix as pointed out by Ubbe, thanks.

All the CC I see are on slot1, I guess CC can be on slot2 as well. Live and learn.

Code:

Changelog
v1.1.0

 Fixed: Calculation did not account for the possibility of 'CC' been on slot2

As usual, please read any documentation supplied.
Any questions, ask away.
Hope it works for you.

Download

HASH: 67e129ead4ef732cf45a8f46005bac41

bravo14 · Oct 4, 2019

Dang I download it and I have win7 x64. I open it and seems only works with 32bit not 64.

Annunaki · Oct 4, 2019

Works fine on my win 10 64 bit system.

bravo14 · Oct 4, 2019

I notice it says 0 kb not sure if it causing not to open? Win7 64bit I'm using.

MtnBiker2005 · Oct 4, 2019

The zip file is around 5 KB

The *.exe is around 24.0 KB (24,576) bytes)

bravo14 · Oct 4, 2019

I get this message when moving from zip file to a folder

bravo14 · Oct 4, 2019

I went and used 7zip and it made a folder and appears to be there now.

TheButcher · Oct 4, 2019

Thanks thewraith2008 !

Annunaki · Oct 5, 2019

Thank you for this tool it is working perfect now I understand what LSNs are.

thewraith2008 · Oct 5, 2019

In an effort to make the program a little more useful beyond the DSDPlus usage, I added a second calculation that hopefully can be used with scanners/other that use a LCN for each frequency (which has 2 slots).

Let me know if it's OK.

Code:

Changelog

v1.2.0

 Added: Calculation to suit DSDPlus and what Scanners/Other use (I think).
 - Just use checkbox to choose calculation. (checkbox state not saved)

 Added: Tooltips
 - 'CC LCN' will show the opposite LCN used.
 - 'Target LCN' will show the opposite LCN used. (shown after value entered)
 - 'Target LCN frequency' will show base frequency. (shown after value entered)
 -- Shown after click 'Calc LCN frequency' and assuming the value of CC frequency/LCN are correct.

 By 'opposite LCN', I mean:
  if DSDPlus calculation used, then tooltip will show LCN for Scanners/Other or
  if Scanners/Other calculation used, then tooltip will show LCNs for DSDPlus.

As usual, please read any documentation supplied.
Any questions, ask away.
Hope it works for you.

Download

HASH: 5d70ed0fb221dcebe502bb16246c8b6a

Annunaki · Oct 5, 2019

Tool tips and DSD calculations work fine here on Win 10 x64.

Cant comment on the Scanner calculations though.

Ubbe · Oct 5, 2019

Works perfect now with both DSD and Uniden scanners.
An excellent tool for managing undocumented systems.

/Ubbe

Ubbe · Oct 5, 2019

I also use LCN calculations when I find frequencies that I suspect are part of a system and add them to the sites with their LCNs in the scanner and see if they get active and on which site. So another click box "Calc Target LCN" would be useful. I could use Unidens LCN finder but it could take days and ties up the scanner, or try different LNC's in the calculator until I hit the correct frequency.

/Ubbe

thewraith2008 · Oct 5, 2019

Ubbe said:
I also use LCN calculations when I find frequencies that I suspect are part of a system and add them to the sites with their LCNs in the scanner and see if they get active and on which site. So another click box "Calc Target LCN" would be useful. I could use Unidens LCN finder but it could take days and ties up the scanner, or try different LNC's in the calculator until I hit the correct frequency.

/Ubbe

OK, just so I'm following you right.
At the moment we use a known CC frequency/LCN with a target LCN to calculate a target frequency.

Do you mean use a known CC frequency/LCN with a target frequency to calculate a target LCN?

Ubbe · Oct 5, 2019

thewraith2008 said:
Do you mean use a known CC frequency/LCN with a target frequency to calculate a target LCN?

Exactly. If it can be done easily without too much work.

/Ubbe

pro92b · Oct 5, 2019

The calculator appears to assume one base frequency and a step size of 12.5 kHz. The sites below do not follow those assumptions and give wrong answers from the calculator.

Code:

Questar-Dominion Barton Peak Site (Sanpete County, Utah)
CH ID     Freq     Color    LCN
649     856.3375     0        324    Base: 848.2625
650     856.3375     0        324    Step: 0.025
729     857.3375     0        364    CH ID = LSN
730     857.3375     0        364
809     858.3375     0        404
810     858.3375     0        404
889     859.3375     0        444
890     859.3375     0        444
969     860.3375     0        484
970     860.3375     0        484

Code:

Vail-Beaver Creek Ski Resort Vail, Colorado
CH ID     Freq    Color
683     454.250     9        Base: 449.9875
699     454.350     9        Step: 0.00625
703     454.375     9        CH ID = LCN
719     454.475     9

Code:

Broward County Local Government Fort Lauderdale, Florida
CH ID     Freq     Color
51     451.625     1        Base: 451
190     453.3625     1        Step: 0.0125
210     453.6125     1        CH ID = LCN
212     453.6375     1
223     453.775     1
225     453.800     1
723     460.025     1
736     460.1875     1
748     460.3375     1
763     460.525     1
3929     472.850     1        Base: 423.75
3935     472.925     1        Step: 0.0125

LCN to Frequency calculator for DMR TIII

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