From: Starsekr: Bill, you get maximum power transfer when the impedance is matched.
Jim, according to the AC (RF) maximum power transfer theorem, you get maximum power transfer when the load impedance is *conjugately* matched. Luckily, coax with a Z0 of 50+j0 ohms is a trivial conjugate match to a 50-j0 ohm load. For a non-trivial example, the feedpoint impedance of an Extended Double Zepp antenna may be 175-j1000 ohms. For maximum power transfer, the impedance looking back down the transmission line from the EDZ feedpoint needs to be 175+j1000 ohms, the conjugate of the feedpoint impedance.
