Used to be the same problem I have. The wireless performance of this routerboard is simply poor without an external antenna. Pinging the router over wireless and you can get 4-digit ms latency.
What I have done is to put the router in an open small book rack, cover 2 sides of the inner wall of the book rack with aluminum foil, then put the end of the router where the internal antenna is located at the corner where the aluminum foil is applied. Now the CCQ vastly improves at >90%.
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