Pixelation Problems

I have been getting problems on certain HOWARD COUNTY, MD HD Channels.  Is there any way to identify what frequency (Channel ID) is being used for specific Xfinity HD Channels?  I see Power and SNR changes eand know that the problem is external to my house (Xfinity acknowledged that but hasn't identified and fixed in 6 months).

Example HD Channels:  814, 816, 819, 823, 825, 826, 829, 831, 832, 837, 838, 839