Using the 'Expert' MMDVMHost Editor
I have been asked a number of times to provide a method for making edits to the /etc/mmdvmhost config file. While the 'Expert' mode editor is not linked from the dashboard, you may use the below links to access it on your Pi to make any specific changes to the config file.
Navigate to the expert edit page;
Make your edits and save the changes.
See this excellent video  on using the Expert Editors included on Pi-Star