Nate, If you look at the D-Star protocol you'll see in AP2 (in the file shogen.pdf) the details of the FEC applied to the header, doubling its length to 660 bits. It's a convolution code as opposed to concatenated block codes as used by AMBE.
The checksum in the header is then used to ensure that the header FEC has done its job. The header data is repeated in the slow data throughout the transmission but without FEC but with the checksum. There is no excuse for a receiving station to get a corrupted callsign bar bad programming. Jonathan G4KLX
