This ripple was first observed at X-band but was later observed in all 8 IF channels. It was later tracked down to be associated with the optical IF links. It appears to be internal to the optical modulator used in the links. It will be present in all receiver spectra with a peak-to-peak amplitude that depends on the IF frequency on the fiber. Some fiber modems may be worse than others, so an inventory should be conducted and possibly the modems with the smallest gain ripple placed in the most frequently used channels. At first the structure appeared to be very stable but in some cases it is clearly visible within a 12 minute total power position swithcing observation. The contractor is aware of the problem and is attempting to make improvements. An improved modulator has been ordered for evaluation. Some results should be available by the end of the year.