Jeff wrote:

BTW, the range PA1-PH9 is only 80 unique combinations, no (or is it only
72 since it seems to exclude '0')? How can that work? Maybe PA1 means
something other than what I am thinking?


The PA1-PH9 is the prefix, so the callsigns run from PA1AAA to PH9ZZZ

Yes byt also from PA1A to PH9Z and from PA1AA to PH9ZZ.

PA0 is excluded as a compromise to old guys who have a PA0 call and
don't want newbies to share that privilege. A proposal has been made
to end that situation but it has not been implemented yet.