Lloyd- I use a Radio Shack AC power adapter model 273-1776, 12 volt @ 1000mA, and a 'M' connector to mate to the K1. It works very well for me. I am very pleased with the K1. I have the four band model. Have worked over a dozen foreign DX stations in a couple of weeks using a 60 foot wire up to a tree, and a 30 foot counterpoise on the ground. Burl F. Updyke W3SOC