How to amplify the signal of a megaphone in a room sheathed with a profiled sheet?

Question

mobile connection

I work in a one-story house sheathed with iron profiled sheet. There is a megaphone signal, but the connection is unstable, it is interrupted. I can't get through (out of network coverage), and I can hardly connect every other time.
You have to jump at the only window to catch a stable signal, but this does not help either - it floats away.
What do you recommend to do?
Thank you.

Answer 1

Well, the easiest way is to buy a low-power gsm repeater. The price starts from 1.5k
For a general understanding