Short term traceable cal gear rentals? - Page 1
Forum section: electronics / general

author: rhb
author_rank: Super Contributor
timestamp: May 08, 2020, 02:57:19 am
content: Would you be interested in short term (e.g. one business week) rentals of references with traceable data for calibrating your gear?I prefer the USA Cal Club version, but there is a lot of commercial gear that is too heavy to meet the Cal Club shipping cost constraint. And the NRE on lighter kit for a lot of things is too high for it to happen.I think I've stumbled into a situation where corporate mergers are causing a lot of old cal gear to be purged, some of which with an OEM cal with data would provide an economical option for people with fairly high end personal labs to do their own annual cals. I think I might be able to negotiate a deal in return for helping the seller with stuff I don't want.General notion is I buy the instruments. The rentals are a proportional share of the cost of OEM cal jobs and shipping costs. So I get my share of the cal cost in return for supplying and maintaining the gear.Generally everything except volts and ohms. I think TiN and Andreas have that well in hand.Reg

author: TiN
author_rank: Super Contributor
timestamp: May 08, 2020, 03:46:56 am
content: It's not realistic. Even if there are 20 people , each ready to pony up cost of shipping 40kg+ kit (calibrator + packaging) insured, nobody would want that much responsibility.Calibration cost of pro calibrators is high (think multiple $k), maintenance even higher. And it's all useless anyway, if there is no understanding of such a machine and all supporting environment behind it.I've actually considered doing it for our internal cal club, with much longer term than a week (1 year per member), but scrapped idea due to napkin cost estimates. And that even considering the fact, that all participating members of such club have experience around the transport 5720A operation and verification procedures. And to make such rental expense meaningful, you must have dozens of high-end insturments that need calibration, not some 6.5 digit DMM, which is very cheap to calibrate at nearest lab.My 5720A's needed to spend no less than 20 days to recover back into their state after shipping, so in one business week you can't even do any measurements.Sure, one may say, no need fancy pancy 7.5-digit calibrators, maybe something simpler and cheaper, like 5440B or 4000/4700 series Datron?. Well, that's even worse, because now you need to ship same 40kg+ kit, and not even get high accuracy in return?It's cheaper just to buy old calibrators off ebay and get them calibrated for your own lab, where you don't have to ponder if somebody misuse the instrument, or worry about validity of performance due to shipping stress.So just take shipping cost of a kit like this, add insurance rate for it, some margin and then you get yourself exactly the number that electronics equipment businesses offer for a loan unit.

author: rhb
author_rank: Super Contributor
timestamp: May 08, 2020, 03:08:51 pm
content: I thought it worth considering the concept, nothing more. And all in one calibrators would be an exception. Other than scopes and meters such things don't really exist except as bespoke systems consisting of 20-30 instruments filling multiple racks. You have to be doing a lot of the same thing to justify the cost of that sort of a set up.From what I saw when picking up my Tek 577 there will probably be much of a 1990's in-house cal lab that is headed for ebay. Certainly good enough for practical needs. I don't need absolute accuracy so much as consistency across instruments with reasonable accuracy. For a lot of RF measurements 100 ppm is all that is practical or required. A selection of standard capacitors, inductors and resistors covers a lot of ground.In the case of my lab, full calibration would require a truck full of gear. There is certainly no such thing as an all in one calibrator that would meet my needs. This is why I'm building an automated switch and attenuator deck from DC to 18 GHz to do regular cal runs. Developing the software for that will be a considerable undertaking and require very detailed understanding of the instruments.Reg

author: e61_phil
author_rank: Frequent Contributor
timestamp: May 20, 2020, 06:58:31 am
content: Quote from: TiN on May 08, 2020, 03:46:56 amI doubt, that the 5720A gives really more accuracy than a 5440B. The specifications are very similar and the stability on the 1kV range is even better on the 5440B (which is interesting for me, but might be not that interesting for calibration purposes). But the 5440B offers DCV only.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: May 20, 2020, 04:23:55 pm
content: Wow, just looked at eBay and the number of GR 1404-A reference caps is amazing. Still can't afford one, but the price is coming down. I wonder if we're on the verge of a surfeit of surplus test equipment?

author: rhb
author_rank: Super Contributor
timestamp: May 20, 2020, 04:57:36 pm
content: I think it likely that a lot of small firms will close or merge in the coming year. A merger was what led to my Tek 577 curve tracer being sold at auction.In the quest for the superfluous, far too many people and businesses run very close to the edge of their finances and even a small downturn will crash them. This is not a small downturn.I've already noticed that LeCroy DDA-120s are listed at 2/3 of what they used to be.Happy cap hunting.Have Fun!Reg

author: rhb
author_rank: Super Contributor
timestamp: May 20, 2020, 05:20:26 pm
content: Jeez, Conrad, the GR 1404-A is an *expensive* bauble. Seems to me you have the skills to make one that was as stable, but not as accurate. I notice that no one lists prices for Invar sheet. You have to ask for quotes.I've got loads of big air variables. Not Invar, but suitably packaged they ought to make good Cal Club standards with rotation disabled after being set as close as possible and stuck in an enclosure as per GR/IET practice.Reg