After knowing the gain antenna that we should select, we still have the following question:
1- The antenna should be female or male connector?
The female RP-SMA connector has the same external housing as a standard or conventional female SMA connector, which consists of an outer shell with the threads on the outside; however, the center receptacle is replaced by a male pin. Similarly, the RP-SMA male has threads on the inside like a conventional male, but has a center receptacle instead of the male pin in the middle.
2- Does anyone buy high gain antenna with RPSMA Connector in European, please recommend us some options.
High gain means less than 27dBi and as high as possible.
Every 3 dBi is going to double the transmit power.
From the website of digi http://www.digi.com/products/accessories/antennas/whip-antennas#models
A24-HASM-450 only has 2.1 dBi gain with RPSMA Connector
A24-P19NF-PP is the one with 19 dBi gain Antenna - 2.4 GHz, 16 patch panel, 19 dBi, N-female.
We have not idea what the N-female means, and we guess it’s not RPSMA Connector.