Signal Strength, Code 771 and Recording Issues

I've had a lot of different problems since I got my HD receiver a few years ago.  Some have come and gone.  I used to have horrible HD channel reception with signal strengths in the 70's.  Then one day all of a sudden it cleared up and all my signals shot up to low 90's.  I've had intermittent problems with TV channels cutting out.  For a while I was having issues with local channels.  Then I was having issues with both locals and other HD channels (Nat Geo, History, Science, SyFy, Discovery, etc.).  Now I seem to just be having issues with the HD channels.  I've even had recordings show up completely blank or just not play at all.  The last two problems haven't happened for a few months (knock on wood).  As for the signal issues though, is my dish out of allignment or is it possible there's just something wrong with my LNB?  Generally speaking it only happens the evenings and when I've recorded a show the box pops up telling me that some or all of the show didn't record due to loss of signal (771).  I can watch the same channels in the afternoon and there's absolutely no problems at all.  I've included my signal strengths in a .txt file if that will help at all.  I have pretty decent signal strengths on my 101, 110 and 119.  My 103ca and 103cb signals look pretty good at the moment.  I can look at them later on and see if they really change that much.

Any insights?