Re: [time-nuts] Calibration procedures - what is normal?
Am Sat, 13 Feb 2016 18:41:02 +1300 schrieb "Dave Brown" : > Cobham is a UK based defence and high end security supplier- > originally formed (not too many years ago) by their buying out of > several other companies in their lines of business. More recently > they have got into aerospace activities. As you might expect, they > supply some rather expensive and exotic stuff. Purchase of Aeroflex > seems like a step in a different direction but who knows? > Well to me, purchasing Aeroflex sounds very much in line with their aerospace activities. Aeroflex itself bought a number of smaller aerospace companies in recent years. So much that is, that some people insist that buying space-related companies is all Aeroflex actually does, full stop. ;-) Florian ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Calibration procedures - what is normal?
I have to say, I'm hugely impressed by the Aeroflex 3413 I've bought and Cobham's customer service response has so far been excellent but I suspect it will be far too expensive for me to buy repair parts which is a shame. On 13 Feb 2016 09:14, "Dave Brown" wrote: > Cobham is a UK based defence and high end security supplier- originally > formed (not too many years ago) by their buying out of several other > companies in their lines of business. More recently they have got into > aerospace activities. As you might expect, they supply some rather > expensive and exotic stuff. Purchase of Aeroflex seems like a step in a > different direction but who knows? > DaveB, NZ > > - Original Message - From: "Joseph Gray" > To: "Discussion of precise time and frequency measurement" < > time-nuts@febo.com> > Sent: Saturday, February 13, 2016 6:00 PM > Subject: Re: [time-nuts] Calibration procedures - what is normal? > > > On Fri, Feb 12, 2016 at 3:43 PM, Richard (Rick) Karlquist >> wrote: >> >> I left Agilent just before the split, but I don't know >>> anyone there who liked that name. Or the logo :-) >>> >> >> Another recent name change (acquisition) that is even worse is >> Aeroflex to Cobham. I realize that Cobham is probably a family name >> that was used when their business was started eons ago, but geez, in >> all these years, they couldn't have come up with a better name for the >> company? Even when it went from IFR to Aeroflex, that wasn't a bad >> name at all. >> >> In the coming fiscal year, we'll be spending close to $100K to buy >> some Cobham (yuck!) service monitors (or communication analyzers as >> they like to call them). Going to P25, the venerable HP 8920A just >> doesn't cut it any more. As for the $100K, we're small potatoes. I was >> told that an unnamed customer recently bought hundreds of units. It's >> like that line "A billion here, a billion there, pretty soon, you're >> talking real money." >> >> Joe Gray >> W5JG >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Calibration procedures - what is normal?
Cobham is a UK based defence and high end security supplier- originally formed (not too many years ago) by their buying out of several other companies in their lines of business. More recently they have got into aerospace activities. As you might expect, they supply some rather expensive and exotic stuff. Purchase of Aeroflex seems like a step in a different direction but who knows? DaveB, NZ - Original Message - From: "Joseph Gray" To: "Discussion of precise time and frequency measurement" Sent: Saturday, February 13, 2016 6:00 PM Subject: Re: [time-nuts] Calibration procedures - what is normal? On Fri, Feb 12, 2016 at 3:43 PM, Richard (Rick) Karlquist wrote: I left Agilent just before the split, but I don't know anyone there who liked that name. Or the logo :-) Another recent name change (acquisition) that is even worse is Aeroflex to Cobham. I realize that Cobham is probably a family name that was used when their business was started eons ago, but geez, in all these years, they couldn't have come up with a better name for the company? Even when it went from IFR to Aeroflex, that wasn't a bad name at all. In the coming fiscal year, we'll be spending close to $100K to buy some Cobham (yuck!) service monitors (or communication analyzers as they like to call them). Going to P25, the venerable HP 8920A just doesn't cut it any more. As for the $100K, we're small potatoes. I was told that an unnamed customer recently bought hundreds of units. It's like that line "A billion here, a billion there, pretty soon, you're talking real money." Joe Gray W5JG ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Calibration procedures - what is normal?
Hi, I had an interesting experience with a local cal lab when I took in my HP 5334B (Option 010). I'd recently purchased the unit and had no idea of its calibration history. At the time I wasn't quite a time nut, and I didn't own a reference to check frequency accuracy myself. I was hoping to get the counter and its timebase calibrated to use as a reference at home. I checked the service manual and got the impression that this was part of the procedure. I also told the tech what I was looking for when I dropped it off. Can you see where this is going? A few days later I picked up the unit, and the cal certificate listed the frequency accuracy as perfect to 9 digits with no adjustment needed. That raised an eyebrow. When I got it home, I immediately noticed the reference selector had been switched to external. Sure enough, no adjustment to the OCXO had been made. They used their lab reference externally during the procedure. I contacted them, they said they followed the listed procedure for this counter, but nonetheless offered to help. I took the unit back and they plugged it in for 10 minutes to let it "stabilize", then gave me the count of their standard on one of the channels written on a sticky note... Needless to say, that experience motivated me to get more serious about this stuff and invest in some good references. Dan On Fri, Feb 12, 2016 at 3:14 PM, Joseph Gray wrote: > I sent my HP 3457A in for cal. I should be getting it back next week. > I won't mention where I sent it, but it wasn't Keysight (I don't like > that name). I recently changed the SRAM battery and purposely did not > save the cal constants. I bought the meter second hand and it wasn't > in spec when I bought it. I didn't care what the past data was. > > The service manual lists an entire sequence of procedures for > calibrating this DMM, starting with storing values for zero and full > scale into the SRAM. All of this is done via the front panel, by > pushing buttons. > > I just found out that this part of the procedure is not normally done > (at least by the lab I sent the DMM to). With no pre-existing cal > constants, the tech I spoke to was rather annoyed that he was having > to spend the time doing the hookups and pushing buttons for each > function and range to store the zero and full scale values. I was told > this added an extra hour to the normal procedure. > > Not knowing what is normally done in the cal lab, I assumed that the > entire procedure as listed in the service manual would be done. It > seems that I was wrong. > > In the end, the lab decided not to charge me for the extra time > involved. I thanked them for that. > > My question is, do any cal labs (including Keysight) normally perform > the zero and full scale procedures as listed in the service manual? > > Joe Gray > W5JG > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Calibration procedures - what is normal?
On Fri, Feb 12, 2016 at 3:43 PM, Richard (Rick) Karlquist wrote: > I left Agilent just before the split, but I don't know > anyone there who liked that name. Or the logo :-) Another recent name change (acquisition) that is even worse is Aeroflex to Cobham. I realize that Cobham is probably a family name that was used when their business was started eons ago, but geez, in all these years, they couldn't have come up with a better name for the company? Even when it went from IFR to Aeroflex, that wasn't a bad name at all. In the coming fiscal year, we'll be spending close to $100K to buy some Cobham (yuck!) service monitors (or communication analyzers as they like to call them). Going to P25, the venerable HP 8920A just doesn't cut it any more. As for the $100K, we're small potatoes. I was told that an unnamed customer recently bought hundreds of units. It's like that line "A billion here, a billion there, pretty soon, you're talking real money." Joe Gray W5JG ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Calibration procedures - what is normal?
The consensus seems to be that I was expecting more than I should have. That's what I get for reading service manuals :-) Other than the confusion over what I was expecting, I can't fault the cal lab I sent the meter to. They are charging me a hobbyist-friendly price and aren't going to charge me for the extra time involved to re-enter the cal data (I offered to pay). If I were using this for business, I would probably have used HP/Agilent/Keysight/whatever they'll be called next month. When I think about it, I really don't know if the DMM had cal constants in it when I bought it second hand. I say this because the battery had previously been replaced. I thought it was original, but when I pulled the board, I could see obvious signs of hand soldering. I had asked the previous owner if the battery had been replaced and he said no. I guess I was lied to. Who knows if the person who replaced the battery before did things properly, so as to save the cal data. When I replaced the battery, I purposely didn't bother saving anything. Once I get the 3457A back, I'll check my EDC VS330 voltage standard. I suspect that it is also out of spec. I realize that I should use a 3458A for this, as the specs on the VS330 and the 3457A are similar. The good news is that the cal lab said that they could probably adjust the VS330 if needed. I emailed them the manual and asked. They said they offer a one hour free eval, so if they decide they can't do it, I'd only be out shipping, if I send it to them. David Kirby - Yes, I do remember your talking about removing the battery in your DMM. As for doing it yourself (at least with the 3457A), yes, if you had the proper standards that were also calibrated. As I recall from reading the service manual weeks ago, the procedure is just hooking up the appropriate standard for each function and range, then pushing buttons on the front panel. I don't have the necessary equipment, so I sent it off. I agree that it would make more sense to have fitted a second battery, or at least some pins on the board where you could easily clip in a temporary battery. Otherwise, you have to solder something in temporarily. Thankfully, modern equipment uses non-volatile memory that doesn't need a battery. Thanks to all for the feedback. Joe Gray W5JG On Fri, Feb 12, 2016 at 4:24 PM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote: > On 12 Feb 2016 21:12, "Joseph Gray" wrote: >> >> I sent my HP 3457A in for cal. I should be getting it back next week. >> I won't mention where I sent it, but it wasn't Keysight (I don't like >> that name). I recently changed the SRAM battery and purposely did not >> save the cal constants. > > You may have seen my recent post on the 3457A. I was tempted to do as you > done, on the assumption that Keysight would adjust the meter to give the > best possible accuracy rather than just leave something untouched if it was > within spec. Someone warned me that if it caused errors at startup, it > might be considered needing a repair rather than just calibration. > > Did the meter indicate in any way that the cal constants were lost? A POST > error or similar? > >> The service manual lists an entire sequence of procedures for >> calibrating this DMM, starting with storing values for zero and full >> scale into the SRAM. All of this is done via the front panel, by >> pushing buttons. > > So does that mean it is something one could do oneself without accurate > standards? > >> I just found out that this part of the procedure is not normally done >> (at least by the lab I sent the DMM to). With no pre-existing cal >> constants, the tech I spoke to was rather annoyed that he was having >> to spend the time doing the hookups and pushing buttons for each >> function and range to store the zero and full scale values. I was told >> this added an extra hour to the normal procedure. > > Ouch. > > I assume this means that your meter is probably calibrated more accurately > than it would have been had any settings left unchanged if they were in > spec. > > I have just bought a battery and intend fitting it soon. I might ask > Keysight about the constants. > > I really can't understand why they don't put two battery holders and a > couple of diodes so a good battery in an one would be ok. Having to mess > around desoldering batteries and hooking up power supplies seems crazy to > me. > > Dr David Kirkby > Managing Director > Kirkby Microwave Ltd > Registered office: Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 > 6DT, United Kingdom > Registered in England and Wales as company number 08914892 > http://www.kirkbymicrowave.co.uk/ > Tel 07910 441670 / +44 7910 441670 (0900-2100 GMT) > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.
Re: [time-nuts] Calibration procedures - what is normal?
Generally, whenever I've had a non manufacturer 'calibration' it's been a certification service that tells you your equipment is within spec and gives you the variances and probability of uncertainty, a pass/fail test. Where equipment was out of spec then any service to bring it within spec was usually charged extra but the level of equipment we needed meant the test year was thrown away and new was purchased it was cheaper than having it adjusted. I sent my HP 3457A in for cal. I should be getting it back next week. I won't mention where I sent it, but it wasn't Keysight (I don't like that name). I recently changed the SRAM battery and purposely did not save the cal constants. I bought the meter second hand and it wasn't in spec when I bought it. I didn't care what the past data was. The service manual lists an entire sequence of procedures for calibrating this DMM, starting with storing values for zero and full scale into the SRAM. All of this is done via the front panel, by pushing buttons. I just found out that this part of the procedure is not normally done (at least by the lab I sent the DMM to). With no pre-existing cal constants, the tech I spoke to was rather annoyed that he was having to spend the time doing the hookups and pushing buttons for each function and range to store the zero and full scale values. I was told this added an extra hour to the normal procedure. Not knowing what is normally done in the cal lab, I assumed that the entire procedure as listed in the service manual would be done. It seems that I was wrong. In the end, the lab decided not to charge me for the extra time involved. I thanked them for that. My question is, do any cal labs (including Keysight) normally perform the zero and full scale procedures as listed in the service manual? Joe Gray W5JG ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Calibration procedures - what is normal?
On 12 Feb 2016 21:12, "Joseph Gray" wrote: > > I sent my HP 3457A in for cal. I should be getting it back next week. > I won't mention where I sent it, but it wasn't Keysight (I don't like > that name). I recently changed the SRAM battery and purposely did not > save the cal constants. You may have seen my recent post on the 3457A. I was tempted to do as you done, on the assumption that Keysight would adjust the meter to give the best possible accuracy rather than just leave something untouched if it was within spec. Someone warned me that if it caused errors at startup, it might be considered needing a repair rather than just calibration. Did the meter indicate in any way that the cal constants were lost? A POST error or similar? > The service manual lists an entire sequence of procedures for > calibrating this DMM, starting with storing values for zero and full > scale into the SRAM. All of this is done via the front panel, by > pushing buttons. So does that mean it is something one could do oneself without accurate standards? > I just found out that this part of the procedure is not normally done > (at least by the lab I sent the DMM to). With no pre-existing cal > constants, the tech I spoke to was rather annoyed that he was having > to spend the time doing the hookups and pushing buttons for each > function and range to store the zero and full scale values. I was told > this added an extra hour to the normal procedure. Ouch. I assume this means that your meter is probably calibrated more accurately than it would have been had any settings left unchanged if they were in spec. I have just bought a battery and intend fitting it soon. I might ask Keysight about the constants. I really can't understand why they don't put two battery holders and a couple of diodes so a good battery in an one would be ok. Having to mess around desoldering batteries and hooking up power supplies seems crazy to me. Dr David Kirkby Managing Director Kirkby Microwave Ltd Registered office: Stokes Hall Lodge, Burnham Rd, Chelmsford, Essex, CM3 6DT, United Kingdom Registered in England and Wales as company number 08914892 http://www.kirkbymicrowave.co.uk/ Tel 07910 441670 / +44 7910 441670 (0900-2100 GMT) ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Calibration procedures - what is normal?
On 2/12/2016 12:14 PM, Joseph Gray wrote: I sent my HP 3457A in for cal. I should be getting it back next week. I won't mention where I sent it, but it wasn't Keysight (I don't like that name). I recently changed the SRAM battery and purposely did not I left Agilent just before the split, but I don't know anyone there who liked that name. Or the logo :-) You need to understand that the mission of service depots at Agilent was mainly to be profit centers. They were not there to make customers happy in order to enhance Agilent sales. At best, they needed to do warranty repairs to support equipment under warranty, but even the whole warranty thing was a way to make extra money, not to sell instruments in the first place. What you describe is perfectly consistent with my experience using them as an internal customer. BTW, they charge internal customers the same high prices they charge for external customers. There is an attitude that it is not worth making reliable products because they can make so much money fixing them. Consider yourself lucky you got the extra effort. They remind me of car dealer service departments, in terms of the business model. Specifically, the "tune up" racket or the XXX,000 mile "service" racket. Rick N6RK Not knowing what is normally done in the cal lab, I assumed that the entire procedure as listed in the service manual would be done. It seems that I was wrong. In the end, the lab decided not to charge me for the extra time involved. I thanked them for that. My question is, do any cal labs (including Keysight) normally perform the zero and full scale procedures as listed in the service manual? Joe Gray W5JG ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Calibration procedures - what is normal?
Joe I will believe they only do that procedure in a real repair. I had to do the same thing on a tek 2465b scope. O man what a complete pain in the rear and literally 8+ hours of work. So I can fully appreciate the reality that a Calibration is a check and trim for accuracy. Most likely an hour or so in total. Regards Paul WB8TSL On Fri, Feb 12, 2016 at 3:14 PM, Joseph Gray wrote: > I sent my HP 3457A in for cal. I should be getting it back next week. > I won't mention where I sent it, but it wasn't Keysight (I don't like > that name). I recently changed the SRAM battery and purposely did not > save the cal constants. I bought the meter second hand and it wasn't > in spec when I bought it. I didn't care what the past data was. > > The service manual lists an entire sequence of procedures for > calibrating this DMM, starting with storing values for zero and full > scale into the SRAM. All of this is done via the front panel, by > pushing buttons. > > I just found out that this part of the procedure is not normally done > (at least by the lab I sent the DMM to). With no pre-existing cal > constants, the tech I spoke to was rather annoyed that he was having > to spend the time doing the hookups and pushing buttons for each > function and range to store the zero and full scale values. I was told > this added an extra hour to the normal procedure. > > Not knowing what is normally done in the cal lab, I assumed that the > entire procedure as listed in the service manual would be done. It > seems that I was wrong. > > In the end, the lab decided not to charge me for the extra time > involved. I thanked them for that. > > My question is, do any cal labs (including Keysight) normally perform > the zero and full scale procedures as listed in the service manual? > > Joe Gray > W5JG > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Calibration procedures - what is normal?
'Normal' calibration is a performance check and adjustments as required Performance checks are applying stimulus and checking instrument response is within the acceptable range. A Full calibration is adjust each parameter to as close as practicable to ideal value and may include new cal constants and is generally far more expensive than a normal calibration Content by Scott Typos by Siri > On Feb 12, 2016, at 3:14 PM, Joseph Gray wrote: > > I sent my HP 3457A in for cal. I should be getting it back next week. > I won't mention where I sent it, but it wasn't Keysight (I don't like > that name). I recently changed the SRAM battery and purposely did not > save the cal constants. I bought the meter second hand and it wasn't > in spec when I bought it. I didn't care what the past data was. > > The service manual lists an entire sequence of procedures for > calibrating this DMM, starting with storing values for zero and full > scale into the SRAM. All of this is done via the front panel, by > pushing buttons. > > I just found out that this part of the procedure is not normally done > (at least by the lab I sent the DMM to). With no pre-existing cal > constants, the tech I spoke to was rather annoyed that he was having > to spend the time doing the hookups and pushing buttons for each > function and range to store the zero and full scale values. I was told > this added an extra hour to the normal procedure. > > Not knowing what is normally done in the cal lab, I assumed that the > entire procedure as listed in the service manual would be done. It > seems that I was wrong. > > In the end, the lab decided not to charge me for the extra time > involved. I thanked them for that. > > My question is, do any cal labs (including Keysight) normally perform > the zero and full scale procedures as listed in the service manual? > > Joe Gray > W5JG > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Calibration procedures - what is normal?
I sent my HP 3457A in for cal. I should be getting it back next week. I won't mention where I sent it, but it wasn't Keysight (I don't like that name). I recently changed the SRAM battery and purposely did not save the cal constants. I bought the meter second hand and it wasn't in spec when I bought it. I didn't care what the past data was. The service manual lists an entire sequence of procedures for calibrating this DMM, starting with storing values for zero and full scale into the SRAM. All of this is done via the front panel, by pushing buttons. I just found out that this part of the procedure is not normally done (at least by the lab I sent the DMM to). With no pre-existing cal constants, the tech I spoke to was rather annoyed that he was having to spend the time doing the hookups and pushing buttons for each function and range to store the zero and full scale values. I was told this added an extra hour to the normal procedure. Not knowing what is normally done in the cal lab, I assumed that the entire procedure as listed in the service manual would be done. It seems that I was wrong. In the end, the lab decided not to charge me for the extra time involved. I thanked them for that. My question is, do any cal labs (including Keysight) normally perform the zero and full scale procedures as listed in the service manual? Joe Gray W5JG ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.