Knowing the difference in SMA and RP-SMA type connectors
When matching antennas to connectors, care must be afforded when it comes to selecting SMA and RP-SMA type connectors. Although they resemble one another, they are different and the two types are incompatible with one another.
This is shown in the diagram below. Center pin placement is the key.
Knowledge Tip: What does “RP” stand for? Reverse Polarity. Extra nerd points: What does “SMA” stand for? SubMiniature Version A.
Extra Reading: Wikipedia article on SMA and RP-SMA Connectors
Though it is not always the case, generally each of the two connector types are used for specific purposes.
Typically an SMA connector is used for cellular RF antennas (2G/3G/4G/LTE/5GNR), and an RP-SMA connector is used for 2.4Ghz WiFi RF Antennas.
Dual band WiFi (2.4Ghz and 5.xGhz) antennas, as well as 5.xGhz WiFi antennas tend to have SMA style connectors.