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"Al" bravely wrote to "All" (14 Feb 05 20:02:01)
--- on the heady topic of "Confused About Noise Floor and Sensitivity" Al From: "Al" Al Xref: aeinews rec.radio.amateur.antenna:5148 Al In QST Jan 2000 the ARRL published some specifications about receivers Al including the Icom R75. Regarding the R75 it stated that the Noise Al Floor (mds) is -130dBm under certain specific conditions. It also Al states that the AM Sensitivity, 10dB (S + N)/N, under the same Al conditions is 1.7uV. Al I am trying to equate the two specs into the same units. -130dBm is Al equal to 0.071uV; 1.7uV is equal to -102.5dBm. That is a difference of Al 27.5dB. Al It is my understanding (and this is where the fault probably lies) Al that 10dB above the noise floor should put the signal at -120dBm, Al which is 0.22uV not 1.7uV. They are putting the signal at -102.5dBm. Al Where is the extra 17.5dB loss coming from? Doesn't 10dB (S + N)/N Al mean 10dB above the noise? Al All input is greatly appreciated. Thank you. Al Al KA5JGV I think it's a typo I calculated 0.775uV not 1.7uV. They might have added a 1 in front of the decimal instead of a zero. A*s*i*m*o*v |