Off grid is used very loosely since it kind of relies on the cell infrastructure. However, a Boefang system can be setup to send alerts via 2 meter.

My own home uses cellular radios for normal security and suffers the same problem.

I work for a company that installs security systems. We do commercial as well. All hardwired. Anolog or digital. No wifi, no internet need. Also a battery BU incase the power goes out it can still record. Its completly self contained.

get some big dogs, hang some ominous looking ropes

I'll stick with my cans on a string