A test method is for determining RF sensitivity of an RF receiver for a plurality of channels extending over a frequency band(s) using an RF source coupled to the RF receiver by an RF communications link. The plurality of channels may include channels having a predictable RF sensitivity and a channel(s) having a non-predictable RF sensitivity. The test method may include measuring an RF sensitivity for one or more of the channels having the predictable RF sensitivity, and generating a partial RF sensitivity function for the channels having the predictable RF sensitivity based thereon. The method may further include measuring an RF sensitivity for the channel(s) having the non-predictable RF sensitivity. Additionally, an overall RF sensitivity function may be generated for the plurality of channels based upon the partial RF sensitivity function, and based upon the measured RF sensitivity for the channel(s) having the non-predictable RF sensitivity.