Yes, I know, this could very well be a controversial topic, so feel free to close this off if you feel it's not a good fit for this site. That said, I'm posting it here because hams (and as a licensed ham, I count myself in that group) know a great deal about radio reception, and in the end, that's the issue.
Since the start of the pandemic, I find myself working in the ham shack (like so many others!). The problem is, the cabin is insulated with foil backed hard foam insulation, which I've noticed reduces radio reception by quite a bit. For HF and VHF signals I have an antenna outside the shack, so that's not a problem. However, I have real issues with mobile phone signals and since the reception is mediocre at best, the insulation just makes matters worse.
So, the question is this: is there a legal and simple way to improve mobile phone reception within the shack that borrows from techniques commonly understood by amateur radio operators? I've been careful about how I worded that question, since what I really need is a solution I can build myself! 73s