What sort of signal being received results in those voltages??
Is it just a carrier, or a tone? or even voice??

 

Most Mosfets have ordinary sensitivity but some also have an "L" version that is more sensitive.
The datasheet for an IRFZ44 shows that some of then are not sensitive and need a gate-source voltage of 4V to begin conducting only 0.25mA between its source and drain.
The datasheet for the IRLZ44 shows better sensitivity and some need a gate-source voltage of 2V to begin conducting only 0.25mA between its source and drain.
Which one did you get?

 

Hi J,
For similar projects, I have used the RX LED as the trigger.
C.