Many antennas of amateur radios are detachable, then customers can replace the higher gain antennas to extend the communication range according to their needs. However, the non-original high-gain antenna connector can't connect to our radio directly, or the antenna is too long to directly connect horizontally, we need to choose a suitable adapter to connect them. So, how to choose the right adapter? Take Retevis RT73 and Retevis MA03 vehicle antennas as examples.
This is the connector of Retevis RT73. It's the common connector for mobile radios, called M-F connector, and the adapter that matches it must be an M-M interface.
This is the connector of Retevis MA02. It's the SL16-J connector, which can also be called M16-M, and the matching adapter must be the SL16-K, which is the M16-F interface.
It can be seen from the above analysis that the adapter connecting Retevis RT73 and Retevis MA03 must be an M-M to M16-F adapter. In theory, it can be directly connected without an adapter, but we usually choose a right-angle adapter for convenience.