SDS100/SDS200: Cap+ Trunked System - Consistently Missing The First Transmission

[Bruin18]

Hi there-

Was looking for some help as I'm using my SDS100 to monitor a CAP+ Trunked system. The system has 6 sites, each with 3 frequencies. I've determined the different TGID's and Color Codes. I've also run the LCN Finder and found 2/3 LCNs on each of the sites. Overall when I'm scanning it's working pretty great so I don't think it's a reception thing...but I seem to almost always miss the first transmission.

I usually hear the person respond to the first transmission and then the rest of the back and forth.

I'm only scanning this System that I set up. I've even tried focusing on just one site and one TGID to limit what the scanner is searching. That didn't make a difference.

I've also tried changing the squelch and changing the hold time (currently set to 2). I have priority ID scan off. I've tried changing the Filter...between Global, Normal, Invert, Auto (i haven't tried wide normal, wide invert, wide auto).

I'm wondering if it's because I've only located 2/3 LCN's on each site. The 3rd LCN is set to 0. I tried setting that to 3, but that also didn't seem to make a difference.

I have a BCD325P2 scanner as well...I programmed the system as conventional on that scanner (it doesn't allow for TGID's) and that one seems to pick up the transmissions better.

Something tells me I'm just not quite set up right.

Any suggestions?

Thanks!

 

[dave3825]

Pretty sure you need all lcn's for it to work properly. Is the system listed in the database here? If so, it may have all the required info. If you imported it, is the db in your Sentinel up to date?

 

[Bruin18]

It’s a brand new system so it’s not listed in the database yet. I’m trying to help figure it out so the system can be listed properly in the database.

 

[buddrousa]

You have to understand how the systems an have to right equipment to acquire the correct information.

 

[Bruin18]

Yeah I get that. An SDS100 scanner should work.

 

[dave3825]

have to right equipment to acquire the correct information.

Yeah I get that. An SDS100 scanner should work.

Think he means sdr dongles and DSDPlus which is useful in determining channel information. Blows Unidens LCN finder away.

 

[tvengr]

I had to let the LCN finder run a couple of days to catch the LCN's on all of the frequencies on a system not in the database. You need all of the LCN's for the system to work properly. To complicate things even more, they were not using all of the frequencies listed in the FCC database. You just need to be patient and thoroughly investigate the system. It takes time.

 

[mciupa]

You'll have to feed us a bone here.

• What's your location?

 

[Ubbe]

but I seem to almost always miss the first transmission.

I usually hear the person respond to the first transmission and then the rest of the back and forth.

I've even tried focusing on just one site and one TGID to limit what the scanner is searching. That didn't make a difference.

Any suggestions?

If you configure it as a OFT system with three sites and three channels in each do you then hear all conversations?

I always use OFT when mapping out a system and if you already know what frequencies each site are using, even the ones that are still to be activated, then it's so much easier. You can even make a site hold to see if it catches all conversations or if you miss a frequency in that site. If it seems to miss a frequency then scan that frequency band for DMR frequencies using the same color code and monitor those to check what TG's they are using.

OFT doesn't care about LCN or the control channels and just scans voice channels, so should be a fool proof tool to use to confirm what channels and TG's go on which site and what frequencies that are actually in use.

/Ubbe