How to perform cal factor correction when using 8480 series power sensor ( with cal factor below 85% or above 100%) with old power meters (HP435B/HP43

If you are using an HP435B or HP436A, the minimum Cal Factor (CF) setting is 85% and the maximum is 100%.

To re-normalize Cal Factor:

To normalize CF values which are reported above 100%, first calculate the new reference CF using the equation:

Where MaxCF is the largest measured CF value and the “Floor” function means rounding down to the nearest integer.
Then adjust all CF Points using the equation:

There is no way to renormalize CF values which are reported below 85% without adjusting some values above 100%.

To correct power without changing Cal Factor:
If the cal factor setting for your frequency of interest is below the meter’s minimum or above the meter’s maximum, set the cal factor control to 100% and divide the reading ( in watts) by the decimal equivalent of the cal factor. For example, if the cal factor is 75%, divide the reading by 0.75 ( this will result in a larger value of power than that displayed by the meter). If the cal factor is 104%, divide the reading by 1.04 ( this will result in a smaller value of power than that displayed by the meter).

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