Hi Dave,
Are you saying you still get the red ring with version 20190621?
Your settings certainly look fine to me. Unfortunately the Hex Code doesn’t work as a filter for Pure Mode C - as Pure Mode C transponders don’t transmit the Hex Code. Instead, the system has to use some very fancy filtering to determine the strongest received signal and then confirm (by watching for any variation in certain parameters) whether or not this is from your ‘Own Mode C’ transponder or from a ‘threat’ aircraft. A considerable amount of work was done by Lee to improve Mode C filtering for the new 20190621 release, so if the system is working correctly, you shouldn’t still be getting the red ring round your own aircraft.
Regards
Peter