Thank you for the suggestion. Our solution for frequency hopping spectrum analysis is the BB60C. It has hardware image rejection and very fast sweeps.
There are a number of solutions for frequency hoppers using the SA44B, but they are generally case-specific and do not work in the general case. If you can keep the hopping to a 20 MHz band, the SA44B can be used with image rejection off (disregard the image responses ~21.4 MHz away), or if the transmissions are long at each hop (>sweep time) you can keep image rejection on and analyze 40 MHz worth of spectrum.
Beyond this, the BB60C is required.