[MilCom] Question

[Collins]

I am wanting to get back into MilCom....obviously the technology has
changed a bit.  When I posted in 2010 or so, I used a RS Pro 2045 scanner
and some time stamp / recording software.

What do I need in order to pick up "Mode-S" and so forth ?  If there is
some sort of website with info about modern tracking, please direct me to
it.

Thank you,

Collins Cogbill
Texarkana, Arkansas / Texas