The hi frequency degradation you refer to at higher frequencies is primarily CNR, carrier to noise ratio. At low frequencies you will run primarily into CSO and CTB, second and third order distortions from the nonlinearities of amps and fiberoptics (including fiber dispersion and self-phase modulation). You can also get contributions in these distortions from FM broadcast band leaking into the system. Seeing that you have 2 tuners displaying the distortion, I would check amplifiers in the system. Most of the cheapy ones will do a decent job with CNR, but obliterate CSO and CTB. Motorola makes several nice hybrid amps for the CATV band that can support CNR's in the 50's and distortion in the mid 60's, much superior to what the CATV company supplies (let alone that Shack place). With that said, I am very glad to no longer be at the fiber optic juggernaut, and happily shocking dogs again! -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.