I agree with @BlakeRichardson .   I have had no end of problems with older Macbook Pro's, especially around roaming when there are multiple APs. ... View more

If your unable to get the MR74, then your only option that I'm aware of is purchasing one of the NEMA enclosures and then retro-fitting it so that the antenna is mounted at the bottom, and you do as much weather proofing (custom) as you cant to ensure no water can get in etc.   Would end up looking sort of like this:   ... View more