43 means your signal is weaker than mine. If you have cable, does your TV have diagnostics that show SNR also? I think the TiVo person may be wrong. If you said it was 5 or 10 then I could see an issue, but 43 is not going to overload your tuner. I am getting my numbers from a Premiere since my Roamio comes Friday. My TV is also 36, but I don't have any dedicated test equipment to be sure.