Yes, if you need to. However, you should leave at least three feet of coax cable, measured from where the cable exits the antenna. Note: This is NOT true for all antennas. CB antennas’ coax generally should NOT be cut. See separate question regarding CB antennas’ cable length. Reasonable lengths of excess cable can be rolled in a coil of at least 8 inch diameter and stowed in an out-of-the-way place.