FastNet on a SDS100

[phyberoptics]

Trying to listen to Fastnet on a Uniden SDS100.

I am monitoring the East Garafraxa site and the db and DSD+ show:
365 422.2625
366 422.2625
381 422.3625
382 422.3625
413 422.5625
414 422.5625

I see the note on the listing to subtract 1 from the channel ID then divide by 2, so in my scanner I now have:
LCN 182 422.2625
LCN 190 422.3625
LCN 206 422.5625

The scanner is still not hearing anything from this system. Is there anything else I need to do to make it work? I've got all service types turned on, and the scanner is in ID Search Mode, but nada despite DSD+ picking up traffic.

Thank you

 

[gary123]

Try Discovery. You should get some TG hits.

I just looked at my local site .hpd (Baden) and I have LCN in the 1400 range. I have not checked the unit for operation as I'm nowhere near a scanner. I suggest look at the LCN for other sites and see if a pattern appears. I'm not sure either if DSD has a setting to display the LCN info. Try a search on TIII and DSD settings.

 

[phyberoptics]

I tried Discovery which churned up nothing, even though DSD had activity.

DSD shows:
Group Call; TG=450-21-901 RID=450-21-671 [T5] Ch=413 TX-422.5625 RX=427.5625

So I know there is activity.

 

[ATCTech]

The only voice channel with activity is 422.5625 and it's reporting 413/414 on DSD+ with no database configured locally. There have been no other active channels/slots in the last 10 minutes.

 

[phyberoptics]

Can anyone confirm what I have in DSDPlus.frequencies as correct for East Garafraxa?

TIII, 13, 1.7, 365, 422.2625, 427.2625, 0
TIII, 13, 1.7, 381, 422.3625, 427.3625, 0
TIII, 13, 1.7, 413, 422.5625, 427.5625, 0

The only voice channel with activity is 422.5625 and it's reporting 413/414 on DSD+ with no database configured locally. There have been no other active channels/slots in the last 10 minutes.

Interesting, I wonder if they aren't using 381 then..

 

[gary123]

My .hpd file agrees with your frequencies.

I did a bit of checking while I had a few minutes.
check out this nice app.
LCN to Frequency calculator for DMR TIII | Page 4 | RadioReference.com Forums
all we need to do is know the base freq for the system and the step size.

I'm going to enter in a few values while I have coffee and see what I come up with. I got 400.000 base LCN of 3 that works for the Durham site

 

[ATCTech]

I've been watching different in-range FastNet sites for the last few days in an attempt to confirm LSNs etc. I have two observations that have not changed since the original data was added to the RR database many months ago.

First, most sites rarely if ever use more than one frequency (the second slot on the CC frequency) despite previously logged activity that clearly displayed multiple frequencies at one time or another. This is not a busy system, even in the Toronto area with the Crosstown LRT construction activity using the network. At worst, or best depending on your persepective, the LRT guys will be talking at the same time as a school bus but that's about it.

Second, and I hope somebody here with a whole lot more knowledge of this flavour of TIII than me can explain, the Toronto site which is the only one local to me that's NOT in the 420MHz range is different again in channel numbering. The CC on 462.1125 is shown by DSD+ as 2981/2982. Fair enough. However, the second voice frequency that activates once in a while is 453.4875 and reports as 3173 for slot 1. This completely blows the DMR (notice that I did NOT say TIII) "calculator" program out of the water (as implied in the documentation) as the LSN number sceme is inverted - lower number, higher frequency. This is being reported by DSD+ with NO frequency, site, channel, etc. etc. files in the executable folder, it's purely what DSD+ decodes.

That's where I'm at today and have been for a long while now. The LSN values for the Toronto site in the DB here are wrong if the on-air data is to be believed via what DSD+ displays and if memory serves I think that's my fault going way back. How any current scanner is supposed to handle this inverted scheme is beyond my pay grade.

 

[gary123]

This system is looking more and more like a one off. If the opportunity presents I will attempt to reverify the hardware in a vehicle.

 

[slicerwizard]

I hope somebody here with a whole lot more knowledge of this flavour of TIII than me can explain, the Toronto site which is the only one local to me that's NOT in the 420MHz range is different again in channel numbering. The CC on 462.1125 is shown by DSD+ as 2981/2982. Fair enough. However, the second voice frequency that activates once in a while is 453.4875 and reports as 3173 for slot 1. This completely blows the DMR (notice that I did NOT say TIII) "calculator" program out of the water (as implied in the documentation) as the LSN number sceme is inverted - lower number, higher frequency. This is being reported by DSD+ with NO frequency, site, channel, etc. etc. files in the executable folder, it's purely what DSD+ decodes.

DFA systems don't need bandplans. No bandplan equals no frequency calculator program.

I suspect that system/site operators can assign arbitrary channel numbers to each RF channel. The Logical Physical Channel Number transmitted with each channel grant could likely be set to the physical base station number (1, 2, 3, ...)

Toronto: TIII, 1000:13, 2.2, 3173, 453.4875, 0.0, 0 ; CC

Ballantrae: TIII, 1000:13, 3.2, 5323, 453.2500, 0.0, 0 ; CC

Obviously, there is no system bandplan in use here.

lower number, higher frequency

Not particularly relevant. Even non-DFA systems can have independent bandplan ranges:

420's: LCN/LSN range x
450's: LCN/LSN range y
460's: LCN/LSN range z

There is no requirement that x < y < z.

Bell Mobility could've done this on FleetNet, for example.

That's where I'm at today and have been for a long while now. The LSN values for the Toronto site in the DB here are wrong if the on-air data is to be believed via what DSD+ displays and if memory serves I think that's my fault going way back. How any current scanner is supposed to handle this inverted scheme is beyond my pay grade.

All DMR receivers are supposed to decode the DFA channel grants. The channel frequencies (TX and RX!) are in every grant. Only need to enter the CC frequencies. Easy peasy.