Abstract: Methods and apparatus for determining operating parameters, such as rain margin, of an antenna by attenuating the received signal by, for example, the use of calibrated attenuation pads, the method comprising placing such pads in front of the horn of the antenna feed until impulses appear on the screen of a T.V. or monitor connected to the antenna. The antenna alignment is peaked by determining the orientation of the antenna that yields the minimum impulses. The rain or impulse noise margin is determined by summing the attenuation factors of the pads with the increase in delta G/T due to the attenuation. The tuning of the receiver can be checked by observing the number of black and white impulses. The positioning of the antenna with respect to the polarization of the signal can be checked by determining the rotational position of the feedhorn which yields the minimum number of impulses. The descrambler dropout margin and clear sky carrier-to-noise ratio are determined by the addition of proper constants.