a good HD antenna is necessary if not near any city and trying to get signal from 40 miles away plus... some are directional and some are not...
hopefully your camping spot is high and not in a valley...
look online for the direction and distance from the local closest transmitter for the channel you need for the game and pickup an antenna from online sources like
MCM Electronics: Home and Pro Audio/Video, Security and Test Equipment
don't forget cable and connectors and a pole or two to mount the antenna to and get it elevated...
I have Sirus XM radio and they carry many games on their channels.
antenna guidelines here:
If you are close to a signal like at HOME, you can use a coat hanger... but then your not camping