I think I may have solved this. In my initial attemps to download the list
to the radio, I don't think I started with a FileNew, and I was just adding
to and editting a (somehow) corrupted data set. If I "new" it first, then
edit it, it will download without error to the radio. I have only put in 25
or so local airport freqs, and nothing at all in the 800 MHz range at all,
so that problem might still be there.