Hi Dick, I am a little confused as to your needs. On the one hand you feel the hp3458A is a fine instrument only needing CAL every 2 years, yet you then say it needed to be CALd every 2 days to stay repeatable. That does not sound very encouraging and is indicative of other problems.
I would like to know why you feel this particular instrument is so crucial ? Particularly as you have within your own means just about everything to verify your own equipment beyond anything reasonably needed. The only item missing from your list is a damn good null meter; the Fluke 845. You have the best there is in a voltage standard with the 732A, assuming they are working correctly and verified (i.e., calibrated) by a highly reputable source like Fluke. Even without the null meter you could easily jump start your own verification process to improve your confidence. The only other NICE thing to have would be Fluke 720A Kelvin-Varley divider. For $1000 you could easily obtain the 845 and 720A. With the 720A you could prove, without doubt, each and every digit in your 7 ½ digit meters, not to mention the 5440B. The race for digits is a fun hobby but a truly wasteful effort because the real world does not operate in a finely tuned calibration lab with every nuance of the environment controlled beyond reason. Even if you had such a lab in the basement (some do), playing around at even just 6 digits requires knowing how to account for a number of not so easily proved variables in the measurement process. Of course, if this is a commercial concern like trying to satisfy a government contract, then all bets are off. Such a game guarantees the race. Bill....WB6BNQ [email protected] Dick Moore wrote: > A couple of times a year, I could really use an HP 3458A. No way can I > justify spending upwards of $4-5k for such limited use. So, maybe some > of us could form a buyer/user group to share the cost of one of these > instruments, which could put it in the range of affordability for > each. For example, ten of us could have the instrument for two weeks > each twice a year, and the cost for each comes down to that for a > 34401A. > > These instruments ship well (at least within the continental US, via > FedEx or UPS), are very stable, and self-calibrate, needing a full cal > (which uses a 10kohm resistor and a 10VDC source) once every couple of > years to keep within tolerable specs. I've rented one once and I found > that it really needed to self-cal once every couple of days to stay > repeatable, especially on ohms and AC. > > My confidence in my Fluke 5440B Direct Valtage Calibrator, two Fluke > 732A 10V standards, and two Datron 1082 7-1/2-digit DMMs would go way > up, not to mention keeping a few other things checked and accounted > for, like resistance standards. > > I'm willing to ante-up up to $1k to get us started, if there is any > interest here among the US time-nuts. > > Best to reply to me at: > [email protected]. > > We can work our details if the interest is sufficient. > > Best, > Dick Moore > > _______________________________________________ > 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. _______________________________________________ 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.
