I'm a long time JTA User and have just looked at GridTracker cuz I like the graphic look of the activity.   I just enabled the JTA rebroadcast to a port 1240 which was there from earlier setup with Log4OMv2 which I no longer use.  Put that port in GridTracker and away I go.  I did read a message from GridTracker author Tag, that UDP being sent were only good for info only.  Since I don't yet know what it's all about, I don't care because it works to see the map.  JTA does all the other stuff.   So since I'm running with setup per JTA help for Log4OMv2, which does not includes using UDP 2237....I switched my rebroadcast port from JTA to 2237 which is what GridTracker likes, and put it back in GridTracker to match, and it works fine.   I'm still only interested in the map, but maybe I will get whatever else.  Good luck.  It works. Send me an email if it helps.  73 Herb WB8ASI