I didn't know EFJ had a national tech force, figured it would be a local dealer.
I looked on ULS for microwave licenses, other than Duke and cell carriers ERS is the only one I see above 5 GHz.
I don't have much microwave experience but I don't recall hearing much about RFI in that band due to the licensing restrictions. I know that vegetation growth and new construction cause problems with paths that had been good over the years.
I wonder if a WISP has a 5 GHz AP that's spewing RFI.