I have one on the mast of the USS Lexington Aircraft Carrier Museum on an amateur repeater where it provides good performance and endures the harsh conditions of the Bay. I opened the original tubes and re-packed it to accommodate the mount in the same box. The antenna spec is 450-470 Mhz, but I have used these down to 441 Mhz many times with good results. Antenna is 4.4' in length and weighs less that 2 pounds.... Antenna will handle 100 watts and requires NO ground plane.