Hi Andy,
Each device needs to be addressed using a different port. For example,
the PC with hb9gce.dyndns.org:1234 and the RemoteRig with
hb9gce.dyndns.org:5678. You need to enter these in your router
accordingly to point to the correct internal IP number, e.g. port 1234 to
192.168.1.10, port 5678 to 192.168.1.11, etc. This way, an unlimited
number of devices can be addressed using the single external IP address.
You actually should always change the RemoteRig to a different port number,
because your router likely already uses port 80.
I hope this helps.
73,
Mitch DJ0QN / K7DX