I'll say again, the argument that "FDR knew" does not in the least depend on just American "code-breakers/crypt-analysts/radiomen."
So, even if we deleted ALL of that information from the records (which obviously FDR's administration tried to do), there would still be many advanced warnings to justify the claim that "FDR knew."
I have quoted just a few of those in these posts. Victor's book is full of them. That's why I suggest again, take the time to study it.
Then, if you can seriously demonstrate that Victor is making false arguments, I and a lot of others I'm sure, will be delighted to hear it!
I already have.