NBC Problems
I talked with DIRECTV Tech Support. They were aware of the problem. It appears it is up to the local affiliate (KNSD San Diego in this case) to get their signal to a common DIRECTV location. DIRECTV takes it from there.
The local NBC folks either had an equipment failure on the HD side of the house, or lost the physical link to connect to DIRECTV.
If you were recording the broadcast in HD, like I was, you were outta' luck....