I am in no way an expert but do you have a leakage detector that you know is right or are these your only two? If you have one available that you know is accurate use it as your verifier and go to any known leak and compare the other two with what you are reading on the one that has been verified, the one that is closest to the reading on the good detector would be the one that is correct? I am sure you would have thought of this but without more detail, as in does it have to be 121.25Mhz and so on i figured i'd start there.
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