i've actually tried to add an external antenna once, it was a quite cheap i bought, thinking that any antenna will at least improve the signal a bit. but surprisingly it even made it slightly worse even when placing it on a high spot and finding its optimal angle.
just wondering if there are any good ones in the market.
unfortunately i can't easily order and return things from the internet because of travelling and not having a permanent address.
thank you so much for the effort Robert!
if anyone else reading this a know something, please don't be lazy and post a messaage, it can helpful for many