SMA Reverse Polarity (also called RP SMA or SMA-RP), is a form of RF connectors that is used on WiFi and 4G WiMax antennas: RP-SMA works on radio frequencies with a range varying from micro to megahertz.
RP-SMA is reverse polarity version of the SMA connector (the SMA connector is used in WiFi, but not nearly as widely as RP-SMA.
Use RP-SMA cable to Upgrade Antenna on home WiFI router running OpenWRT or PineApple Mark IV: All of the WiFi routers that run OpenWRT or PineApple Mark IV V come with a removeable antenna – a small dipole omnidirectional antenna of 5dBi gain with an RP-SMA right angle connector. After removing the antenna, observe the jack or connector for the antenna: It is an RP-SMA female jack. You can easily upgrade the antenna, mount the new antenna where you want, and use a coaxial cable assembly with an RP-SMA male connector, to connect the WiFi access point to the antenna.