Batboard

I have purchased a Motorola CM300 programmed for "Receive Only" for both wide and narrow band AAR channels and i have a antenna with a BNC connecter that I want to use and also I got a Mini UHF to BNC connecter for the radio and im wanting to know if that will be the right adapter to use so I can use the antenna. Also can the CM300 do the 7.5khz frequency step? Thanks for any information.

if it's all recieve only you can adapt it any way you want

Does it have to be a commerical antenna in order for it to work with the radio or can i use my VHF Motorola railscan antenna and it'll work just fine?

Any antenna properly tuned for the railroad band and using 50 ohm feedline should work great. An adapter in line won't make or break your reception.

And yes, the CM300 will work with the new channel spacing on the railroad band. I know of several locations where CM-series radios are being used on the railroads already.

HTH

If the radio is going to move around a lot you might want to look for someone to crimp a Mini-UHF on the antenna for you.. adapters add weight and stress to the connector on the radio, and they love to snap off if you're not careful. PL259-Mini UHF adapters are notorious for this.

As long as the antenna you want to use will cover the range of frequencies you want to monitor, and antenna in the range of 150-160 will work fine on the AAR channels.
A group of my friends are all rail fans and did campouts on the UP line near Gila bend in AZ. And many used portables with antennas 'tuned' for use in the 2 M band segment, but worked very well in the 161 range to easily hear the comms from Omaha, as well as the detectors along the route, wih many detectors being heard 15 miles away.