Are transducer factors in an 8590EM Series subtracted when entered as positive values?

Yes!The antenna factors, cable factors, and other factors are to be entered positively as "losses." For a cable the numbers are typically very low. (.3dB at 30MHz to 2.3dB at 1GHz) This would be entered as a positive number. For a device with gain, like preamplifiers, the factor will be entered as a negative number. For example, if you specify:An antenna factor at 300MHz of 20 dB.A cable factor at 300MHz of 2dB.An amplifier factor at 300MHz of -23dB.then: (20 dB) + (2 dB) + (-23 dB) = -1dBThe analyzer will, at 300MHz, take its "raw" reading, add the factors, and display 1 dB lower!!! This is due to the analyzer knowing that the path before the input has a 1dB overall gain and the reading will be at the plane of the antenna. If the result was positive the analyzer will display a higher value to make up for the loss in the path.