I would suggest approaching the problem methodically. You know that the amplifier is inoperative, so that would be the logical first step. Could be simply a GFCI tripped, or a breaker. Do you have an inverter, or are you plugged into shore power?
Even if the antenna is toast, you should still be able to get some kind of signal after the amplifier is operating unless the coax is shorted someplace. Use your multi-meter to methodically trace out the cables, as described earlier. Good Luck..!