Blocking test for receivers
So what is meant by testing the receiver at &quot;3dB above the required
sensitivity&quot;? And why this 3dB is the benchmark for the blocking test?

&quot;Receiver sensitivity&quot; is how small an antenna signal it can successfully demodulate to produce an adequately recovered signal i.e. a received message with a fairly reasonable signal-to-noise ratio.
So, if you set the input antenna's radio signal at 3 dB above this limit, you are assured of a decent demodulated signal. It should be noted that 3 dB is a doubling of the power received by the antenna.