*Answer:* When making 75 ohm measurements, we recommend using a minimum loss pad to match the 75 ohm impedance to the 50 ohm impedance of the analyzer. A minimum loss pad has an insertion loss of 5.7 dB for which you can enter this loss into the analyzer for it to correct for. Also, you can choose under the Input – RF Input setting to use 75 ohm for the input Z correction. Please see the following FAQ: http://www.home.agilent.com/agilent/editorial.jspx?cc=US&lc=eng&ckey=529371&nid=-11143.0.00&id=529371