Changing the antenna will break compliance for whichever country you are in, and may even break the law as well. So I am afraid you are on your own on this one. We advise you not to change the antenna.
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Contrary to popular belief, humorous signatures are allowed. Here's an example...
“I own the world’s worst thesaurus. Not only is it awful, it’s awful."