It seemed odd to me. The whole idea had the the aura of a April Fool's Joke post.
If it is a joke, it's not fair dating it 3/31 instead of 4/1

Sarah


Marc Ramsey wrote:
I'll take it back, Mode A and Mode C are transmitted the same way, and
while altitude is Gray encoded, the squawk code is straight binary. So,
I have no idea what the NTSB was talking about.

Marc