I have a new RB751U-2HnD and we want to setup the router to use the External Antenna (MMCX) Connector. Under the HT tab we set this to Antenna B but when we are directly in front of the antenna we only get 2 bars on a device.

in the manual it says this.

RB751U has 3 built-­‐in wireless antennas
• Chain0
o one antenna for TX
o one antenna for RX
• Chain1
o one antenna for TX/RX
o MMCX connector for external antenna

To enable the external MMCX connector, set „antenna mode: antenna-­‐b” in RouterOS
wireless settings, in the HT tab of Winbox. Note: enabling the external antenna disables
the built-­‐in Chain1 antenna.

How I read this is that by enabling the antenna b setting it disables the Chain 1 which is the mmcx connector.

So my question is how do I enable the external antenna on this routerboard?

Thanks
Phil

I could be doing it wrong, but my signal got way stronger by setting antenna mode b, uncheck chain1 rxtx, check chain0 rxtx