I will be going to Maryland several times this year. Do the MSP still use their low band system or have they converted to a TRS? If they have converted, is the TRS information on this site? I see only the low band frequencies.
Here is what I can provide, Frederick county has them on the TRS system there, but it is just a rebroadcast of the 39.400 low band channel, same with the SO, 39.020. West of Frederick they run all low band base/mobile all the way to Garrett county and the WVA line.
Some on the Eastern Shore are using 800, and when they are out of range, they revert to low band. MSP Glen Burnie is on the county system, but they too use their old 39.04 frequency. MSP Annapolis no longer exists; that barrack was closed this past spring.
I often hear MSP Waterloo on the Howard county system, but rarely, if ever, do I pick them up on their 39 mhz freq. The opposite is true for Golden Ring - I hear them frequently over their usual 39 mhz freq, but haven't noticed them use their talkgroups on the Baltimore county system all that often. To be honest, when I'm in Baltimore county, I am usually watching the roads more carefully - I really need to put an audio alert on my 396 when Golden Ring uses the County system, so I know they are actually there.
MSP uses lowband in all 23 counties, and they also use the TRS in almost half of those counties. There is currently no statewide MSP TRS, but MSP barracks almost always piggyback onto the county trunked system, where there is one in a particular county. The state buys portable trunked radios compatible with the county's system, and there is always a patch between the TRS and the MSP lowband freq used in the county. It most cases, it's a two-way patch, but there are one or two counties where the person who oversees the county system will only allow a one-way patch. These patches are necessary since MSP is a statewide department, with troopers travelling across county lines while criss-crossing the state both during and when going to or from work. Without the patch, troopers not actually assigned to the barrack in a specific county would have no radio contact with the barrack.