I think it makes it too complicated to post a meetup request.

It should be as easy as here on HN:

Hello! I think Hamburg in Germany needs a good solopreneur meetup. If anyone is interested, let me know!

This is what I would have posted, but I got stuck somewhere along the long signup process.

Thanks for the feedback! I see you did manage to post your activity in the end - nice.

The sign-up form only asks for name, email, password and a pre-filled location - there's some quick "Interests" selection after that, but I felt it was fairly easy/quick to fill out. Maybe I could move that out of the sign-up.

Which part specifically felt too complicated? I'll revisit it and see if there's anything else I can shave off or make it smoother!

Makes me wonder if an RSS feed with a namespace extension for a GPS coordinates field would be enough, with a basic Web page client with a radius limited with a reasonable default based on threshold of results and user adjustable.