SDS100/SDS200: How Would The Uniden SDS100 Behave If A New MotoTRBO Trunk System Were Programed With Frequencies From More Than One System?

[JASII]

As posted above, if you programmed a MotoTRBO trunk system with frequencies from more than one system and each frequency was its own site, would the Uniden SDS100 display all traffic if it was in the ID SEARCH Mode? Also, would it perform best with an LCN of 0 or 1 (or something else)?

 

[gary123]

The scanner will ignore any voice freq not used by the selected control channel. The big issue will be if you have two control channels. the scanner will lock on to the first one it hears and then trunk track from it. This means sometimes it may lock on to one channel other times the other.

 

[Ubbe]

How it works are that it scans thru the channels programmed to a site until it detects the control channel data and will lock on to that.
That control channel sends out LCN info at what LCN a conversation starts and it then checks if it should follow that TG and go to that LCN voice frequency channel or ignore it. After a TG call have ended it doesn't check any more frequencies in that site (but stores the last active site number and goes directly to that in the next scan cycle) and jumps to next system.

It doesn't matter how many extra channels you program to a site, it will ignore those as it will only follow the LCN channel info from the control channel and tries and find that LCN number in the channels you have programmed.

If it comes to a site and lock to a control channel but there's no active conversations, it will then go to the next site in that system and check that control channels activity during the system hold time.

/Ubbe

 

[n1chu]

From what /Ubbe has written, no, your idea is sound but as /Ubbe has stated, the first control channel the scanner detects will determine the LCN order… sounds to me like simply adding frequencies to another “like” system wouldn’t allow the scanner to scan any faster than if you had entered both agencies separately. Corrections welcomed.

 

[Ubbe]

Your scanner will look thru the channels you have programmed to a site in the order you have programmed them. If you first have entered a lot of voice frequencies and the actual active control channel are the last one then it will scan channels at a rate of 80ch/s but if one of those channels open squelch then it starts to try and decode any signal and will give a considerable delay to the scan rate and you loose a lot of valuable time. It will work almost by the same principal as a Whistler scanner doing DMR trunking but worse.

Some systems, I believe some Max Cap, don't use any voice channels programmed and have a bandplan its using. If the control channel use LSN1 and a frequency of 800.0000MHz then LSN 3 will be 12,5KHz higher in frequency at 800.0125MHz and all LSN numbers follow that bandplan. LSN are what the system uses and are one channel number for each slot, two for each frequency, and Uniden uses LCN that are one channel number for each frequency. I believe LCN are used to bypass some patent issues but are more inefficient as when the scanner goes to a voice frequency it has to detect which slot the wanted TG uses and start monitoring it instead of going directly to the slot if using LSN numbering scheme.

/Ubbe

 

[Ubbe]

I where thinking about Direct Frequency Assignment DFA mostly used in Capacity Max systems, where the control channel sends out a voice frequency to go to and not any LCN/LSN numbers. Then you'll only need to program a control channel frequency without any voice channels.

DMR TIII systems use a fixed control channel frequency, but can also use an alternative one, that could use a fixed bandplan but voice channels with a LCN number still needs to be programmed for it to be able to work.

/Ubbe