Mike Monett wrote: > > For more detail see: > > > http://tf.nist.gov/timefreq/service/fms.htm > > Thanks very much for the link. It is curious they don't seem to > spend much effort on correcting the user's frequency errors. They > just want to report how much they are off. > > Why is that? You'd think they would perform a more valuable service > by applying advanced techniques to adjust the user's equipment to > minimize the error, then report and certify the actual result. Is > there some reason they want to leave the user's equipment > free-running? >
Mike, One of the worst perturbations is that of man himself. Unless one is highly knowledgeable of the effect of an adjustment, usually the act of the adjustment is worst then if it had been left alone. In the world of the "Primary masters," they do not make adjustments, only compare differences and then report those differences. Typically, the standards that are inter compared are of such high quality construction that adjustment is neither possible nor wanted. For inter comparisons, a device of known quality is measured before it starts its journey around the labs, of course it is measured at each lab and then upon return is measured again at the lab where it all started. No human adjustment is ever performed. This way mostly just environmental factors influence the portable reference device and much of that can be mitigated with careful record keeping during its trip. In the case of the "FMS" you mentioned, the only difference is the devices being compared are not being moved. The same methodology still applies however. Bill....WB6BNQ _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
