Re: Getting calibration equipment calibrated

Dave Peterson

For fun last night I characterized my bench DMM with my PG506 in DC mode. I was able to use the deflection error to determine that the entirety of the DMMs range held to within 0.2%. Up to the 100v output of the PG506.

So, having compared my oranges to be the same, I am now ready to make apple pie!

I'm at least getting lots of great references to research on my own. I think the conclusion is, for what I'm doing, no, paying a cal shop isn't really worth the money. I'm not splitting atoms here. I should be able to at least say I'm using crab apples to make apple pie.

On Monday, May 24, 2021, 9:41:00 AM PDT, Dave Daniel <kc0wjn@gmail.com> wrote:

I use one of these. And one can send it back for recalibration.

https://dmmcheckplus.com/

DaveD

On May 24, 2021, at 12:22, Jeff Dutky <jeff.dutky@gmail.com> wrote:

﻿Dave,

for a voltage reference you can get something quite economically (less than \$25) on Amazon or eBay that is based off  an AD584:

https://www.ebay.com/itm/254166950181

This should let you get a good bead on your meters. Of course, if you have more than a couple meters you can just take the average of their readings and call it good enough for government work (or for DIY calibration).

They say that the man with several multimeters never knows the correct value of a measurement, but you can just average them all together and get a pretty good bracket. Also, if you are measuring a "known value" (e.g. the voltage on a new battery) you can get a good idea of 1) how close your meters are to true, 2) the variance is across your meters, and 3) which meters read low or high and by how much.

Frequency standards can be had almost as cheaply:

https://www.amazon.com/WSDMAVIS-Frequency-Reference-Oscillator-Interface/dp/B08R6VQRC3/ref=sr_1_2

everything I saw on eBay was more expensive, but also looked like it was higher quality:

https://www.ebay.com/itm/383586682637

or you can buy a brand new GPSDO from Leo Bodnar for \$140 + s&h:

http://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301

but I know that you already have a tinySA, which will probably serve as a frequency reference too (maybe also as a voltage reference?). Throw in a couple of random TCXOs, average across several different frequency counters, and again, you're good enough for government work.

-- Jeff Dutky

Re: Getting calibration equipment calibrated

Dave Daniel

I use one of these. And one can send it back for recalibration.

https://dmmcheckplus.com/

DaveD

On May 24, 2021, at 12:22, Jeff Dutky <jeff.dutky@gmail.com> wrote:

﻿Dave,

for a voltage reference you can get something quite economically (less than \$25) on Amazon or eBay that is based off an AD584:

https://www.ebay.com/itm/254166950181

This should let you get a good bead on your meters. Of course, if you have more than a couple meters you can just take the average of their readings and call it good enough for government work (or for DIY calibration).

They say that the man with several multimeters never knows the correct value of a measurement, but you can just average them all together and get a pretty good bracket. Also, if you are measuring a "known value" (e.g. the voltage on a new battery) you can get a good idea of 1) how close your meters are to true, 2) the variance is across your meters, and 3) which meters read low or high and by how much.

Frequency standards can be had almost as cheaply:

https://www.amazon.com/WSDMAVIS-Frequency-Reference-Oscillator-Interface/dp/B08R6VQRC3/ref=sr_1_2

everything I saw on eBay was more expensive, but also looked like it was higher quality:

https://www.ebay.com/itm/383586682637

or you can buy a brand new GPSDO from Leo Bodnar for \$140 + s&h:

http://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301

but I know that you already have a tinySA, which will probably serve as a frequency reference too (maybe also as a voltage reference?). Throw in a couple of random TCXOs, average across several different frequency counters, and again, you're good enough for government work.

-- Jeff Dutky

Re: Getting calibration equipment calibrated

Dave,

for a voltage reference you can get something quite economically (less than \$25) on Amazon or eBay that is based off an AD584:

https://www.ebay.com/itm/254166950181

This should let you get a good bead on your meters. Of course, if you have more than a couple meters you can just take the average of their readings and call it good enough for government work (or for DIY calibration).

They say that the man with several multimeters never knows the correct value of a measurement, but you can just average them all together and get a pretty good bracket. Also, if you are measuring a "known value" (e.g. the voltage on a new battery) you can get a good idea of 1) how close your meters are to true, 2) the variance is across your meters, and 3) which meters read low or high and by how much.

Frequency standards can be had almost as cheaply:

https://www.amazon.com/WSDMAVIS-Frequency-Reference-Oscillator-Interface/dp/B08R6VQRC3/ref=sr_1_2

everything I saw on eBay was more expensive, but also looked like it was higher quality:

https://www.ebay.com/itm/383586682637

or you can buy a brand new GPSDO from Leo Bodnar for \$140 + s&h:

http://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301

but I know that you already have a tinySA, which will probably serve as a frequency reference too (maybe also as a voltage reference?). Throw in a couple of random TCXOs, average across several different frequency counters, and again, you're good enough for government work.

-- Jeff Dutky

Re: Getting calibration equipment calibrated

Stephen Hanselman

Walter,

I second your comments. We had a “cal-light” lab. Two GPSDO’s and a HP3458 and a set of Julie labs precision resistors. The 3458 got the stds lab cal at keysight (\$1800) and then everything was aligned to that unit.

Our customers did not consider us a cal lab but a repair station. They were required to use specific labs which caused problems. We received MANY pieces of equipment that “didn’t pass cal” that merely required doing the entire calibration procedure carefully. Even with our loose definition of “cal to zero” we never had a unit rejected by the same lab that failed it originally.

Be careful with who you choose for your cal facility, there are a few good ones and many “Lick and Stick” operations.

Regards,

Stephen Hanselman
Datagate Systems, LLC

On May 24, 2021, at 07:58, walter shawlee <walter2@sphere.bc.ca> wrote:

﻿Outside calibration is complex situation, especially since it is understood differently by the
providers of the service, and their customers. this disconnect can be severe, and often leads to
some significant unhappiness on the part of equipment owners.

I documents all olf this in detail when I was writing for the AEA (Aircraft Electronics Association),
you can grab those articles HERE on our site:
https://www.sphere.bc.ca/test/data.html

look halfway down the left hand yellow area where you see the AEA logo. "understanding calibration"
be aware that you will likely get your gear back just as you sent it, with no improvement at all.

I love metrology, and the whole idea of chasing precision to wind up with things as accurate as possible.
I have a GPS, three rubidium standards, and three high end OCXOs I cross check just to get a clean
known 10.000000Mhz value for doing counter calibration. This path is NOT for everyone, and no single standard,
without regular external validation is of any value in the calibration world. Every lab should have some known
references as a sanity check, even if it's just a few precision resistors and known frequency. Known DC voltage
can be harder, and known AC voltage harder still.

One of my best friends runs a metrology lab here, and I watch what he has to go through each year to
have traceable accredited standards, it is not for the faint of heart. I am eternally grateful he helps me
with my cals, or I could never really be sure of anything.

all the best,
walter

--
Walter Shawlee 2
Sphere Research Corp. 3394 Sunnyside Rd.
West Kelowna, BC, V1Z 2V4 CANADA
Phone: +1 (250-769-1834 -:- http://www.sphere.bc.ca
+We're all in one boat, no matter how it looks to you. (WS2)
+All you need is love. (John Lennon)
+But, that doesn't mean other things don't come in handy. (WS2)
+Nature is trying very hard to make us succeed, but nature does not depend on us.
We are not the only experiment. (R. Buckminster Fuller)

Jon Harrison-Hughes

Hi all,

Having repaired the power supply I've now powered the 'scope up. I've measured the calibration signal on all 4 channels, the buttons and switches all seem to work and the self tests pass.

However I seem to have an issue with brightness on the display, particularly with the readouts

1) The traces only appear if the A intensity is turned towards fully clockwise, readable but not exactly burning the phosphor! (self test shows this pot can be adjusted between FF and 00)
2) If the readout pot is turned fully clockwise the readout can be seen very faintly, much fainter than the traces
3) Pressing beam find blanks the display completely

Any hints and tips on where I should start with this issue ?

Thanks,

Jon

Re: P6302 / AM503B 330MHz Oscillation Where is this from?

Albert Otten

(continued) No pronounced resonance with SG503 either. Albert

You normally won't check these current probes with sine waves far above 50
MHz. I tried this with the 220 MHz - up generator because of the mentioned 330
MHz. There was a slight increase in AM503 output about 380 MHz, not very
convincing. Have to repeat this with the SG503. Did you ever try this?

Albert

Re: Tektronix 2246A power supply repair and safe bench testing

Jon Harrison-Hughes

So having repaired the power supply I've powered the 'scope up and tested the LV outputs on J1204, supplies are as follows

+5.24VDC
+5.24VDC
-5.27VDC
-15.96VDC
+14.81VDC
+7.41VDC
-7.50VDC
+58.5VDC
+131.9VDC
+159.8VAC

I had to adjust the trimmer to get the -7.5V within spec which in turn increased the +5V nearer the limit of +5.3V but the supplies are all within spec. I'm going to leave it set here whilst I investigate and repair other issues with this 'scope.

Jon

Re: Getting calibration equipment calibrated

Harvey White

There's a lot of stuff you don't need to do unless you want to.

Remember that the analog scopes you're checking, unless they have digital counters (7D15, et al), you're deciding whether or not you read to the edge of the trace, the middle of the trace, or the other edge of the trace.  Check the specs on the scopes to see what accuracy you *can* read them to.  3%?  You don't need a six figures accurate counter or DMM to set that.

For frequency, you can easily take any available counter and check it to a packaged oscillator.  Then find one that's calibrated (you do have access to that) and see what it reads on that one.  Or if you don't, you're getting close.  Ditto with the voltmeters.

Rise time, well, that is a possible problem, and if you're going after that, you do need bandwidth.

Harmonic Distortion?  Either a good distortion meter at that frequency, or a spectrum analyzer, or a scope with an FFT.

Flatness?  bring on the high bandwidth scope.

However, how much do you need those particular measurements? Most people calibrate the timebases, vertical and horizontal sensitivity, look at the risetime, look at the bandwidth, and let it go at that.

For digital scopes, I'm not even sure you *can* adjust any of the timing.

Harvey

On 5/24/2021 12:31 AM, Dave Peterson via groups.io wrote:
Hmm,

Seems kind of a mixed bag then. I would love to get my own level and time references setup. I have only superficially heard about using GPS based clocks/timing. Seems this might be my opportunity to learn up on that. And thanks for the level reference link Sean. I'll follow up on that too.

The spectral requirements of the SG503/504 sounds out of my league. When opening up my wallet for a place like Keysight, are we talking 100s? It certainly can't be more than, say, \$500 for calibrating one plug-in? Can it? But paying for professional services does get expensive fast.

On Sunday, May 23, 2021, 9:24:27 PM PDT, Eric <ericsp@gmail.com> wrote:
For timing a good (lots of digits) frequency counter hooked to a GPSDO will get you where you need to know then you time reference Is based on the GPS clocks which are HIGHLY accurate. At least WAY more accurate then a 400 series scope at 3%. I did a TG501 and a 184 in my lab with a DMM, Frequency counter, and 100 Mhz scope. There is one adjustment in the 184 that you have to balance 2 trigger points these are the 2 bright spots the should be level.  But the SG503 and 504 need spectral purity characterized as well as the SG503 needs that odd 50 Ohm cable. I have to tare in to my 503 it kind of went nuts on me when I was working on a 465. Sorry for the 2 replies I started this on the small screen and moved to the large one.

Eric

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of Dave Peterson via groups.io
Sent: Monday, May 24, 2021 12:06 AM
To: TekScopes@groups.io
Subject: [TekScopes] Getting calibration equipment calibrated

Hi All,

How much does it cost to get PG506s, SG503/SG504s, and TG501s calibrated?

I can certainly search for local calibration facilities, but having no experience at all: do they tend to be amenable to DIYer's, is the cost in the realm of reasonable, is it worth it?

I have a PG506 that's working beautifully, but I can't be certain that the voltage levels are in spec.

The SG503 seems to work, and I can tell pretty well that it's level above 100MHz, but only on an un-calibrated 7854 scope. So while I feel good about the 100MHz scopes I'm testing with it, no one could call that calibrated.

The TG501 is dead, the SG504 blew a fuse when pressed the "ref" button. So those will need some repair. If I can get them working it would be nice to add them to the calibration set.

It'd be really nice to have all four of these officially calibrated. That'd give me assurance that the scopes I'm repairing are properly tuned up. I don't have any means at hand otherwise to verify level or timing. I could keep working on finding means of establishing standards for level and time. But would it just be more cost effective to pay for calibration?

Thanks,
Dave

Re: Getting calibration equipment calibrated

Outside calibration is complex situation, especially since it is understood differently by the
providers of the service, and their customers. this disconnect can be severe, and often leads to
some significant unhappiness on the part of equipment owners.

I documents all olf this in detail when I was writing for the AEA (Aircraft Electronics Association),
you can grab those articles HERE on our site:
https://www.sphere.bc.ca/test/data.html

look halfway down the left hand yellow area where you see the AEA logo. "understanding calibration"
be aware that you will likely get your gear back just as you sent it, with no improvement at all.

I love metrology, and the whole idea of chasing precision to wind up with things as accurate as possible.
I have a GPS, three rubidium standards, and three high end OCXOs I cross check just to get a clean
known 10.000000Mhz value for doing counter calibration. This path is NOT for everyone, and no single standard,
without regular external validation is of any value in the calibration world. Every lab should have some known
references as a sanity check, even if it's just a few precision resistors and known frequency. Known DC voltage
can be harder, and known AC voltage harder still.

One of my best friends runs a metrology lab here, and I watch what he has to go through each year to
have traceable accredited standards, it is not for the faint of heart. I am eternally grateful he helps me
with my cals, or I could never really be sure of anything.

all the best,
walter

--
Walter Shawlee 2
Sphere Research Corp. 3394 Sunnyside Rd.
West Kelowna, BC, V1Z 2V4 CANADA
Phone: +1 (250-769-1834 -:- http://www.sphere.bc.ca
+We're all in one boat, no matter how it looks to you. (WS2)
+All you need is love. (John Lennon)
+But, that doesn't mean other things don't come in handy. (WS2)
+Nature is trying very hard to make us succeed, but nature does not depend on us.
We are not the only experiment. (R. Buckminster Fuller)

Re: P6302 / AM503B 330MHz Oscillation Where is this from?

Albert Otten

Dennis, in your pictures I see about 3 periods of oscillation in 20 ns. Isn't that corresponding to 150 MHz in stead of about 300 MHz? (I hesitate to bring this up...).
I tried this with similar setup, HAPG, AM503/A6302, 7854/7A29s. I used 5 mA/div to avoid noise. And guess: I also saw oscillations about 3 periods per 20 ns! These oscillations (excited by the rising and falling edges) fade away long before the next pulse occurs. Hence there is nothing to see prior to the rising edges.
You normally won't check these current probes with sine waves far above 50 MHz. I tried this with the 220 MHz - up generator because of the mentioned 330 MHz. There was a slight increase in AM503 output about 380 MHz, not very convincing. Have to repeat this with the SG503. Did you ever try this?

Albert

Re: 2465B on a 200C scope cart?

Jean-Paul

Sorry I mixed up 200, all of my carts are K212

Jon

Re: Getting calibration equipment calibrated

Eric

Hi Dave,
Ok that changes a LOT of things. If you have access to that lecroy you should be set to do the calibrations on all the plugins. A 6.5 Digit DMM is plenty for the PG 506 did mine on a keithly 6500. What is important is you know that when you set the controls of the plugins they are outputting that you think they are and have confidence in them. Especially If the LeCroy has FFT functions you can actually get rid of the spec an requirements cause the LeCroy can check the spectral purity of the 503 and the 504. During the cal process that is really just to make sure the harmonics and spurious signals are at an acceptable level. Even if you can get all the way there you will have them checked to the limits of the LeCroy which means you will be good to go for a 400 and even 7000 series scope. Vertical accuracy of a 465 Is only +/- 3% when the PG is checked with a DMM at DC and adjusted, You run at 0.0025% but then you know you are good to tune 3%. If that makes sense. I can take a look at the spec sheet of the LeCroy if you would like but I will need to model number. I expect you will be perfect for the calibrations the only question is can it FFT this might be a "software option" and not base functionality. The fastest a PG506 needs for calibration is to check a 1ns rise time so only 350Mhz I would imagine the LeCroy is 1Ghz+ so doing a final check on the 3 plugins should be well in it wheel house.

Eric

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of Dave Peterson via groups.io
Sent: Monday, May 24, 2021 1:18 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Getting calibration equipment calibrated

I might be a bit of an odd bird: I quite enjoy twiddling the variety of pots vs. pure automation. I work in the IC industry, so I get my fill of high level integration, and have spent many hours in the lab with high-end scopes. I could quite easily, and may yet, take in some equipment to check in out at high speed. I'll have to talk to the lab manager. This habby came up after the COVID lock-down. Haven't been in the lab since.

Here's a video of our lab showing our first HBM DDR. I did timing closure on the HBM Phy.

It would be worth seeing, for example, the actual edges coming out of the PG506 as captured on a LeCroy.

After so many years stuck on Si die I quite enjoy the tactile nature of the old scopes. I enjoy tearing them down, giving a good cleaning, fixing their little problems, and making them live again. I'm sure my interests will evolve as I progress.

Thanks for the inputs.

On Sunday, May 23, 2021, 09:38:51 PM PDT, Mark Goldberg <marklgoldberg@gmail.com> wrote:

Keysight and Tektronix will calibrate anything for anyone that brings money. They are pretty expensive though. There are good third party calibration labs, and bad ones. Search for ones with NVLAP or A2LA accreditation or maybe ANAB accreditation. Compare their uncertainties (which they should be able to provide) to the desired accuracy for what you want to calibrate.

I keep a subset of my test equipment calibrated and compare the rest. I get one Scope / Spectrum Analyzer and one Fluke multimeter done. For frequency, GPSDOs are so good I don't see any reason to pay for a frequency calibration of anything, at least for my level of usage. I'm set up to measure frequency very accurately based on a GPSDO and use one as a reference for all my test equipment.

New equipment with computer control have automated calibration routines and are way cheaper to do. Older equipment with lots of pots to turn take a lot of labor and you will pay more. My MDO3024 Scope / Spectrum Analyzer cost about \$140 to calibrate and my Fluke multimeter about \$40 at a third party lab. The quote for my HP 8642A signal generator was about \$300 (lots of pots to turn). Tektronix wanted about \$500 for the scope calibration. I think they provide big discounts to good customers, but not to me.

Regards,

Mark

On Sun, May 23, 2021 at 9:16 PM Sean Turner <sdturne@q.com> wrote:

Dave,

Time standards are easier than ever now, as there are a plethora of
GPSDO products around. That will be orders of magnitude better than
crude) Bulova branded OCXO in my Type 184 to many more decimal places
than needed for scope calibration. I do leave the 184 plugged in at
all times so the oven stays hot.

For DC voltages, you can find things like this:
https://www.ianjohnston.com/index.php/onlineshop/handheld-precision-di
gital-voltage-source-v2-detail

With a few things like that on hand, you can easily know that a CRO is
in good shape. Probably not sufficient for more accurate instruments
that require incredibly good calibration accuracy (>=6.5 digit meters,
spectrum analyzers, etc), but will serve you fine for oscilloscopes.

As for professional cal services, I do know Keysight will work on
personally owned stuff (and a lot more old HP stuff than you might
think, a lot of that is still in service in pro labs), but get ready
to open your wallet. Especially if you want NIST traceable.

Sean

Re: 547 Restoration conundrum

Jason A.

Thank you for the recommendations all!

I took a look at the neck as best I could without fully removing it and I don't see any spare magnets or damage inside the tube neck itself. That said, I will need to get it removed to fully inspect it and I haven't had sufficient time for that yet. The Mu metal shield doesn't look like it's suffered any trauma that I can see. At one point in time, I used to have a tape head demagnetizer - I'm pretty sure it has been relegated to the bottom of a box somewhere probably 20 years ago. Once I can put my hands on it, I may try running it over the outside of the shield unless anyone knows this to be a bad idea. Otherwise, I think what I may do is live with it until I can find another CRT for mine. So long as I know what it is doing wrong I can accommodate it in my observations. At some point I will want it to be more correct but for now it sounds like I'll have to wait for a decent CRT to show up to fully fix it or at least fully troubleshoot it.

I really appreciate all the discussion and links to the 475 with similar issues. I'll be curious to see if I can find anything amiss in the neck once I get the CRT out of the shield.

P6042 Probe

Rick

Hi all, is it possible to install and adapt a P6302 probe tip into a P6042 tip? The transformer is bad on my P6042 probe.

Thanks

Re: PG506 Repair - I had a Great Day today/

tek_547

Hi Albert, interesting stuff and info but I have the coming period almost no time for my hobby. An urgent repair in the garage and my car, so when there is more time I dive in again and post the results. Sorry for that...

grtz and stay safe, René

Re: 2465B on a 200C scope cart?

Dave Daniel

I tried doing that when I received my 2465B a while back. The combination of the 2465B and the 200C seemed very unstable. I bought a K212 cart for a very reasonable price and that works just fine.

DaveD

On May 23, 2021, at 23:53, Jeff Keyzer <jeff@mightyohm.com> wrote:

﻿I have a 200C scope cart that I use with my 465B. I'd like to put my 2465B
on the scope cart, but the feet on the 2400 series scope don't line up with
the little plastic cups that keep the scope from sliding off the cart. I
know that at one point Tek suggested that the 200C can be used with the 2400
series scopes. My question is, were there special retaining "cups" for the
2465B to adapt it to the hole pattern on the tray, or did they expect you to
remove the cups, lash the scope to the tray and hope that it doesn't slide
off?

Re: My eye sensitivity to blue-violet higher than normal

ISTR that there are a number of people who have four types of colour sensors which extend vision into what most call the low-UV.

David

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of Carsten Bormann
Sent: 24 May 2021 02:18
To: TekScopes@groups.io
Subject: Re: [TekScopes] My eye sensitivity to blue-violet higher than normal

On 2021-05-24, at 01:34, Mark Vincent wrote:
I have NO problem in seeing, focusing or any form
of eye strain on light that is in the high frequency part of the spectrum
of blue to violet, including indigo.
Well, you’re a mutant then.
(I’m not joking; you might very well be [2].)
Any other anomalies in your color vision?

Re: 2465B on a 200C scope cart?

Dave Seiter

Until a few weeks ago, I had a 7704A on one of the carts meant for portables (forget the model, but it's the one with larger rear wheels).  I needed extra straps to anchor it down and careful knots/tensioning, but it had been there about 10 years without incident.  I only replaced it with a 465 because I've gotten more clumsy recently, and the 7704A was a tad top heavy.
-Dave

On Sunday, May 23, 2021, 11:28:50 PM PDT, Jean-Paul <jonpaul@ix.netcom.com> wrote:

Hello, good question:

I have several  2465/7/B and  carts.

Not a  problem to mount the scopes,  feet and straps need careful  fiddling to position.

I recall t scope rests about 1" forward of the expected position so front cover can fit.

The  feet  on the scope were not  removed.

Finally the straps must be carefully secured or the scope can fall off at high tilt angles.

Bon Chance,

Jon

Re: 2465B on a 200C scope cart?

Jean-Paul

Hello, good question:

I have several 2465/7/B and carts.

Not a problem to mount the scopes, feet and straps need careful fiddling to position.

I recall t scope rests about 1" forward of the expected position so front cover can fit.

The feet on the scope were not removed.

Finally the straps must be carefully secured or the scope can fall off at high tilt angles.

Bon Chance,

Jon

Re: Getting calibration equipment calibrated

Dave Peterson

I might be a bit of an odd bird: I quite enjoy twiddling the variety of pots vs. pure automation. I work in the IC industry, so I get my fill of high level integration, and have spent many hours in the lab with high-end scopes. I could quite easily, and may yet, take in some equipment to check in out at high speed. I'll have to talk to the lab manager. This habby came up after the COVID lock-down. Haven't been in the lab since.

Here's a video of our lab showing our first HBM DDR. I did timing closure on the HBM Phy.

It would be worth seeing, for example, the actual edges coming out of the PG506 as captured on a LeCroy.

After so many years stuck on Si die I quite enjoy the tactile nature of the old scopes. I enjoy tearing them down, giving a good cleaning, fixing their little problems, and making them live again. I'm sure my interests will evolve as I progress.

Thanks for the inputs.

On Sunday, May 23, 2021, 09:38:51 PM PDT, Mark Goldberg <marklgoldberg@gmail.com> wrote:

Keysight and Tektronix will calibrate anything for anyone that brings
money. They are pretty expensive though. There are good third party
calibration labs, and bad ones. Search for ones with NVLAP or A2LA
accreditation or maybe ANAB accreditation. Compare their uncertainties
(which they should be able to provide) to the desired accuracy for what you
want to calibrate.

I keep a subset of my test equipment calibrated and compare the rest. I get
one Scope / Spectrum Analyzer and one Fluke multimeter done. For frequency,
GPSDOs are so good I don't see any reason to pay for a frequency
calibration of anything, at least for my level of usage. I'm set up to
measure frequency very accurately based on a GPSDO and use one as a
reference for all my test equipment.

New equipment with computer control have automated calibration routines and
are way cheaper to do. Older equipment with lots of pots to turn take a lot
of labor and you will pay more. My MDO3024 Scope / Spectrum Analyzer cost
about \$140 to calibrate and my Fluke multimeter about \$40 at a third party
lab. The quote for my HP 8642A signal generator was about \$300 (lots of
pots to turn). Tektronix wanted about \$500 for the scope calibration. I
think they provide big discounts to good customers, but not to me.

Regards,

Mark

On Sun, May 23, 2021 at 9:16 PM Sean Turner <sdturne@q.com> wrote:

Dave,

Time standards are easier than ever now, as there are a plethora of GPSDO
products around. That will be orders of magnitude better than needed for
branded OCXO in my Type 184 to many more decimal places than needed for
scope calibration. I do leave the 184 plugged in at all times so the oven
stays hot.

For DC voltages, you can find things like this:
https://www.ianjohnston.com/index.php/onlineshop/handheld-precision-digital-voltage-source-v2-detail

With a few things like that on hand, you can easily know that a CRO is in
good shape. Probably not sufficient for more accurate instruments that
require incredibly good calibration accuracy (>=6.5 digit meters, spectrum
analyzers, etc), but will serve you fine for oscilloscopes.

As for professional cal services, I do know Keysight will work on
personally owned stuff (and a lot more old HP stuff than you might think, a
lot of that is still in service in pro labs), but get ready to open your
wallet. Especially if you want NIST traceable.

Sean

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