I know this is an antique thread, but that statement bugs me. A properly tuned and matched antenna acts as a transformer in that it matches the impedance of free space to the impedance of the transmission line. The impedance of the antennas output port has no bearing on the antennas efficiency.Because best power transfer occurs when source impedance is same as antenna, and free space impedance is 377 Ohms so 75 Ohm antenna would give very poor results.