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I had a chance to work on monitoring the MGM Grand DMR trunked system in Las Vegas over the last weekend and wanted to share what I found.

First, the MGM system used to be a Motorola 900 MHz analog system for years. There were originally 4 frequencies:
937.2500
937.7375
938.1500
938.2375

At some point a while back the system went from analog to DMR Tier III. The other website still lists these same 4 frequencies as DMR with no LCNs listed. If you load this system in a Uniden scanner, it scans but you only hear occasional traffic - clearly not set up correctly.

I ran the system through the Uniden "LCN Finder" on the 436 radio and came up with these LCN's, all Color Code 5:
937.2500 - LCN 2217
937.7375 - LCN 2219
938.1500 - LCN 2252
938.2375 - LCN 1088

The LCN for the fourth frequency seemed a bit odd, but the radio started picking up more traffic than before, but it was clearly not picking up everything. So I pulled out my Airspy SDR and watched the 900 MHz band with the input sensitivity very low so I would just see what was near by. Watching the spectrum, I determined that the system has 6 active frequencies, all CC5, including the control channel:
937.01250 - LCN 2161
937.02500 - LCN 2162
937.71250 - LCN 2217
937.73750 - LCN 2219
938.15000 - LCN 2252
938.23750 - LCN 2259

So this actually seems to let the 436 scanner track the system with much better accuracy, and the LCN numbers seem to line up better. But, I had another local listener try these in his Uniden 536 scanner and he said it didn't work for him.

- CP

_________________
--
Chris Parris
Federal Wavelengths columnist
The Spectrum Monitor Magazine
chrisparris@thefedfiles.com

CP I vaguely remember this on my 436 -- and found that putting the channels in order by LCN (from low to high) seemed to work best. The SDS-100 doesn't seem to mind either way.

Thanks for all the reports and tips . Special thanks to Will . Hope to go back someday .