Great choice! I have a couple of Advanced Receiver preamps. They work great. I especially like the P150VDG, 150-160Mhz +24dB GaAsFET preamp. This thing is unbelievable on VHF-Hi. My scanners connected to this receive all kinds of transmissions that even my ICOM and Motorola VHF-Hi commercial radios will miss.
They are powered by a 12V power supply. You can purchase one from Advanced Receiver or from Radio Shack. You can also use a Radio Shack 12V DC car adapter. As with all adapters, just make sure you wire it with the correct polarity.