We were planning to use a spectrum analyser in order to do the radio test on the nrf52-dk. Where should the analyzer be connected? Should it be connected to the J1 connector on the nrf52-dk?
Also J1 connector is SWF type. Are SWF and SMA connectors both of the same type ? If it is, then would this cable work ?
Yes you can use the J1 connector to connect the analyzer. It works as a switch and will disconnect the trace antenna when you connect to it. SWF and SMA are not quite the same as the SWF is smaller.
Be sure to use cables and connectors designed with a characteristic impedance of 50 Ohm.
Thanks Jorn. Do you have any suggestions on where can we find such connectors ? Since our oscilloscope has a BNC connector, we want to get a SWF to BNC connector.
In order to connect from SWF to BNC, you have to go through a SMA cable/connector, and then you need a SMA to BNC converter. SWF <-> SMA <-> BNC. See this page for the SWF/SMA probe, + need a SMA to BNC adapter.
But note that you should make sure that your oscilloscope actually support 2.4 GHz signal before buying any cables or adapters. Many BNC oscilloscope only support a couple hundred MHz, and is not in the GHz range.