OK doin better here now. Tnx for yr patience.
Account → more features.
Position-only flights = enab.
Activity log now incl flights w/o flight plan.
Can see 2ATRC → Prague.
There are different kinds of callsigns. Not sure what kind you were inquiring about. My 4-character reply was accurate but may not have been the kind you were asking about.
Flightaware hovering over Prague for 2-xxxx departure(s). Still tinkering to learn site features.
Open Catalog.
Click create new thread.
Post an image, description of the thread you want to create, and captcha. That's all. The image you post is what will show up in the catalog, so pick something that will look OK as a thumbnail & will signify the thread's contents visually.
It's just like making a post only there has to be an image too.
Then bookmark your new thread after creating it.
Be aware that if your thread doesn't get much use, it will slide off the catalog and disappear after a while. So keep using it to keep it alive.
Easy peasy.