I've seen outdoor enclosures for some of the popular helium miners, I suggest you purchase one of those if you want to keep it outdoors.
Aside from that, Rokland makes some nice, low-loss antenna cables that will help out if you want to keep it inside.  They make a 10' cable that has only a 0.4 DBi loss, and a 16' cable with a 0.6 DBi loss.  10-15 feet (~3-5m) should be sufficient for you to keep your miner inside and the antenna outside - which would solve both of your problems.  Look for MPD-400 or higher cables to stay low-loss.