Steve,
To solve the dynamic DNS issue, I asked Brian to setup a hostname in the AMPR DNS with a CNAME record instead of an A record, which referenced a dynamic hostname.
Basically, when someone resolves your CNAME record, it will provide the dynamic hostname, that hostname is then resolved for its A record.
https://en.wikipedia.org/wiki/CNAME_record
As an example, perform a NSLOOKUP on kb3vwg.ampr.org you'll note that it's a CNAME record to a dynamic DNS name; that name is also used for my 44Gateway (instead of the IP).
73,
Lynwood KB3VWG