DEFINITION
 
Receiver Blocking (aka Desense) occurs when a received signal is weakened or blocked by an external source of interference.
 
 
Testing via a Repeater using 2 handhelds
 
When testing using a repeater, the transmit frequency of radio "A" being sent to the repeater is offset from the receiver frequency "B".
 
When using 2 radios located side by side, one is transmitting on a different frequency than the other's receiver. This will overload (desensitize) the receiving handheld and blank out the receiver.
 
 
How to Test
 
Transmit - When using a repeater, identify with your call sign. When the PTT is released, you will hear the repeater's signal briefly confirming that you are using the proper frequency and access tones.
 
Audio - Set both radios to a simplex channel and listen to the signal directly. What you hear is what the repeater will hear.
 
 
Conclusion
 
If you can hear each radio with good audio on Simplex, and you can bring up the Repeater, you're 'Good to Go'.