Radio waves do not penetrate steel or aluminum so you are battling physics. It's not as if folk haven't tried.
So while the 300 feet is at the edge of off the shelf gear, the shielding really kills it.
Has anyone gone over wireless basics with you? I can't here at length but can give quick yes or no's.
Looking for a decent wireless router that can reach a minimum of 300' outdoors, go through 3" of ply plus thin sheets of steel and/or aluminum (1/4" max). It will be on a closed network (not looking for any sort of internet connection to boost or spread). Also, not too pricey, given that I have this stolen from me too often.

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