Bill, Would a Josephson Junction standard need to be calibrated?
Adjusted and maybe compared, yes, but you should not need to calibrate a primary standard? Years ago we had HP Cesium Frequency Standards at work. There were primary standards and good to 4E-12 with no additional calibration. Joe On 1/18/2014 3:37 PM, Tom Miller wrote: > Can you imagine what it would cost to get that calibrated? > > Tom > ----- Original Message ----- From: "Bill Gold" <wpgold3...@att.net> > To: "Discussion of precise voltage measurement" <volt-nuts@febo.com> > Sent: Saturday, January 18, 2014 5:17 PM > Subject: Re: [volt-nuts] What made a HP3458A so expensive > > > In fact if you look at a 1982 HP catalog you will see that the 3456A was > selling for around $3,700 and given inflation the 3458A is still a pretty > good bargain when it was introduced in 1989. In 1989 the 3456A was selling > for $4,600 while the 3458A was selling for $5,900. I wonder if there will > > ever be a "3459A" 9.5 digit meter? With a super miniture Josehpson Junction > for a reference? > Bill > > ----- Original Message ----- From: "Tom Knox" <act...@hotmail.com> > To: "Discussion of precise voltage measurement" <volt-nuts@febo.com> > Sent: Saturday, January 18, 2014 1:29 PM > Subject: Re: [volt-nuts] What made a HP3458A so expensive > > > Actually in spite of it's high price I feel the 3458A represents a bargain. > When it was introduced in 1989 it was $5900. A price it held for decades. > Although designed in > then 80's it's accuracy is still unsurpassed. The 8846A is much less > expensive because it has only about a quarter the parts. With few that > are hand selected and/or aged. And all though both meter have well > executed designs the result is the 3458A has about a magnitude greater > accuracy. And anyone in Metrology can attest to the fact that the cost > of accuracy is exponential. But the thought I wanted to contribute to the > dialog is the real value of the 3458A is the body > of knowledge built around the thousands of 358A's some running > continuously for nearly three decades. The characteristics of the 3458A > are perhaps the best documented of any electronic instrument ever made. > That is priceless. When comparing that body of knowledge to individual > units I have found every 3458A is a little different and seem to each > have their own personality. In a side note, recently I owned what appeared > > to be the original 3458A. I cannot remember the serial number, but it had > the numbered stickers identifying the boards that can be seen in the > original service manual. And it was still working flawlessly. > > Thomas Knox > > > >> Date: Sat, 18 Jan 2014 17:41:26 +0100 >> From: frank.stellm...@freenet.de >> To: volt-nuts@febo.com >> Subject: [volt-nuts] What made a HP3458A so expensive >> >> Well, >> >> the 3458A now is in production for about 25 years , and only around 50k >> units have been sold. >> (That's an estimation by Joe Gellers series number collection) >> >> As the 3458A is a niche product with homeopathic series volume, the >> development, verification/validation, special reliability engineering, >> selection and burn-in measures, QA costs had to be paid per unit in the >> beginning. >> >> To my opinion, especially the 3458A was designed mainly for military >> requirements (Tamb 55°C). The military was willing to pay a premium (HP >> = High Price) at that time. So HP was able to realize that price. >> >> All that development budget is long paid, and after end of the Cold War, > >> the military does not order so many devices anymore, what caused the >> problems of the T&M business (finally => Keysight, urgh!). >> >> But as that market is tight, competitors are few, so the price is not >> going down, instead it's increasing over the years, from $5900 to around > >> $8500. >> >> It would be interesting to calcualte the BOM of the 3458A. >> As they use many custom specific components, it should be relatively >> expensive. >> >> >> >> There is no parameter in the HP3458A specifications, that the device has > >> to be powered constantly to meet the specs. >> Those very high 8ppm/yr. drift might apply only during continuous >> operation. >> During power down, the LTZ should not drift at all, as the ageing >> mechanism is driven by temperature. >> But there might be (there are indeed) considerable hysteresis effects. >> >> I have set the temperature of my HP3458A to ~ 60°C, I shut it down after >> usage, and the periodical comparison to 3 other references shows a drift > >> of less than 1ppm/year. >> >> Frank >> _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.