mmcp42:
your frequency meter looks pretty accurate too
so how do you tell if the frequency meter or the frequency standard is off?
or do you assume the standard is good and adjust the meter?
Yes, any calibration/validation procedure is based on some 'standard' or 'reference' you have avalible to you. The better the standard the more accurate your procedure will be. The old rule of thumb is that your standards or references need to be 10 times the accuracy specification of the thing you are attempting to calibrate.
Of all the electrical measurements possible, frequency is the one that has the best standards and accuracy avalible. That Rubidium Frequency Standard requires no adjustment, it's based on a fixed property of the wavelength of Rubidium, thus making it a very desirable frequency standard.
Lefty