Jinze,
Let's put our semantics on side...
The bottom line is you wish a practical means of? discrimination from unwanted EMI. You may use a tuned loop antenna at each frequency of interest? in order to minimize the effect of EMI, testing it in your city EMI environment.
For this severe EMI enviroment a proper impedance matching will not help at all.
Again all your tested amplifiers will not minimize external picked up by antenna electrical noises. Loop antennas with their directivity pattern might not help either ( let's say your broadcast signal comes from same direction as EMI source ).
You may try a space diversity antenna arrangement. However, none will have 100 % proofed solution for you.?
Raphael
