swinging signal on Spectrum Analyzer

I was in our Satellite Production Vehicle trying to downlink a Ku signal. I was not able to tune it in so I checked my Spec An to make sure the transponder was up. What I found was that my signal was drifting side to side (frequency, not amplitude) at a rate of about twice per second. I was running on generator, which has never been a problem before. I also had some high voltage power lines within 20 feet of the dish. I found that I was able to lock on to a larger transponder (Bandwidth, no amplitude) but not the smaller signals.
Has anyone seen this before?

Can I get a little help with this please? Any ideas?

If you explained in detail what your circuitry was, someone might have an idea. Without that, all we can say is that you screwed up somehow.