If that Leica antenna is the same one as the antennas that were sold on Ebay a few years back, they run just fine on 5V. I have used them on Thunderbolts quite a bit. ------------------------ > I decided that the Leica choke ring antenna I got a while back took 12 volts because the power input went to an 8 volt regulator, and I figured 12 volts should work ok.