Agilent 8902A Opt 050 Accreditation

[Top Gun Test]

Good to hear about the 11812A and how it is verified and again
we get into the Piston attenuator and laser used for distance .
Know I don't want to burst the bubble but I still think the
11812A is just used for the verification and not really to the
proper specs of the option 050 . So with that being said
and we where alluding to the piston attenuator being used to
calibrate the option 050 , I would conclude that you look for this
type of service , because of course you will be getting a accredited
cal and it has to be correct . I know the option 050 cal has been always
a strange topic that everyone sherked around . Boy the confusion
is getting larger . Hawaii did Keysight say that they could do a accredited
8902A option 050 cal ? OR are you SOL We will get this solved for you !!
And MetVets that shed a lot of light on the subject !!!! Thanks .

[MetVet]

If you want to prove your 8902A meets option 050 specifications, you will require a calibrated 11812A verification kit.  This kit will help you prove it meets the specifications.  If you want this discipline accredited, it is my understanding that the kit will need to be accredited,  as well as all the other items used in the calibration of the 8902A.  You will then have to do a line item uncertainty calculation and have it approved by your accreditor before it can be added to your scope.

You can choose to have as many parameters of the 8902A accredited as you want, but your accreditor will require the proof of your uncertainty calculations (at least they are supposed to require that), for your scope to include those parameters.  You will also need to have a measurement assurance program in place to make sure those parameters are scored for proficiency testing during the period of your accreditation.

What I'm really getting at is this is a complicated, time consuming, and expensive venture and if you want to have all the parameters of the 8902's performance specifications accredited, please make sure the payback is good.  If it is, then this is very doable, but if Keysight won't accredit the 11812A, you may have issues getting it listed on your scope.  The best step is to contact your accreditor and ask for guidance.

As far as optimizing the 8902A's specs for option 050,  it is my understanding that if you have performed the adjustment procedure for the 8902A (some work but not too complicated), then the unit should pass the verification described in the performance test.  If it doesn't pass, then you have to start looking for errors in your calculations, the measurements provided on the 355D, or worse.....

[Hawaii596]

To clarify to MetVet, I do have an HP 11812A, along with some HP 8902A's with -050.

I do understand what is involved in this accreditation.  We are already accredited in many areas, and I am fully familiar with doing the uncertainty budget etc.  We do have all of the other pieces in place, and we are in process of adding a number of RF areas to the scope of accreditation.  This one has just been a little troublesome with Keysight not providing accredited service for this.  Even in looking at their scope of accreditation, it looks like they are well able to do ISO17025 calibrations on this.  But it also looks like it might be a business decision (which I find a little confusing) to no longer do what I think is a relatively simple calibration for a high end RF/microwave lab such as theirs - even though it appears they are capable.  My guess is that they may review line items to maintain their fully automated procedures, etc. (including automated collection of uncertainties for), and if it is out of support/too old, it gets dropped if there isn't enough demand to pay for continuing maintenance of the above.  A notable exception is the 478A-H76, which is one of the only standards available, and it would create a big hole in the metrology community if that were dropped.  But the 11812A is likely not so fortunate (old, probably very low demand).

I just looked on Keysight website, and when you search for calibration prices for 8902A-050, it recognizes the model, but does not list what services are available.  When you search on 8902A, they do list up to and including ISO17025 Accredited for the standard model, but no reference to Option 050.  I'm not sure why the issue.  I just sent an additional email to a customer support rep at Keysight to see if they will do an accredited cal to the 8902A including accrediting the option 050 to better uncertainties.  We'll see how that goes.

What I believe I will pursue is finding an accredited vendor to calibrate the special edition 355D (with N connectors, and 10 dB stick attenuators attached).

So I am guessing that if I find another lab to do an accredited cal on the 11812A, they do not measure the attenuation values of the two stick attenuators, and that they are attached to minimize SWR.  And, I should get the attenuation values of the 355D in accordance with the manual (of which I have a hard copy).  I'll have to take a look to see if there is an SWR spec to be tested.  Basically I just need a good accredited lab that can do high accuracy attenuation measurements at 30 MHz.  Any recommendations of a high accuracy attenuation calibration lab?

[chinman]

Check with U.S. Army Primary Standards Laboratory.  They can provide the accreditation for the 11812A.  Our organization has been using them since Keysight no longer provides the accreditation.

[Hawaii596]

Thanks very much for the input regarding APSL.  I am looking into that.  I'll be looking into what ever level of uncertainty I will legitimately be able to use based on the whole context on them.  APSL looks to be a very high end lab.  Just need to go through all of the various uncertainty contributors, etc.  Have to get accredited for Signal Generators, Power Sensors, etc.  They both will be fun.  If anyone has any uncertainty budgets for any of those they may be willing to share offline, send me a PM and we can discuss email address (don't want to post them here).

[griff61]

APSL looks to be a very high end lab.

They are. The APSL is actually the standard NIST uses for some measurements

[Hawaii596]

And in full fairness, after a few emails, I received input from Keysight that they actually can do an ISO17025 Accredited cal on the 11812A.  Price to have it done be APSL is a little higher than Keysight.  Any thoughts on which would give me the better numbers (MU and readings)?  I have my thoughts, but want to hear from some who have worked with both labs (and I know they both are very good labs).

[microwave-kevin]

You might also look into using an NMI but for this I would recommend a Programmable Step Attenuator, benefit is many frequencies and the entire attenuation range (even though with the 8902 procedure you are only looking at the first 50 dB), you can expect something like this:
   S2,1          S2,1          S1,2           S1,2
(MHz)Mag(dB) u(Mag)(dB)   Mag(dB)   u(Mag) (dB)
0.03   -10.028   0.003   -10.028   0.003
0.03   -20.043   0.003   -20.043   0.004
0.03   -30.071   0.003   -30.071   0.003
0.03   -40.03   0.003   -40.03   0.003
0.03   -50.061   0.003   -50.06   0.003
0.03   -60.074   0.006   -60.074   0.006
0.03   -70.102   0.008   -70.102   0.008

 

[CalLabSolutions]

Now that is a good question?
Who has lower uncertainties / better calibration APSL or Keysight...

I have been to both labs and they are both at the top of their class.  To that is a very hard question.

Mike.

[griff61]

And in full fairness, after a few emails, I received input from Keysight that they actually can do an ISO17025 Accredited cal on the 11812A.  Price to have it done be APSL is a little higher than Keysight.  Any thoughts on which would give me the better numbers (MU and readings)?  I have my thoughts, but want to hear from some who have worked with both labs (and I know they both are very good labs).

I might be a bit biased, but I trust the numbers out of the APSL more than I do Agilent/Keysight/HP...Danaher?
In part because of Agilent's tendency to fudge some things, for instance the calibration of an N1911 (needs .1%) with an E4419 (.6 %) and then implying that the E4419 was calibrated at NIST to a spec a little over 400% better than it's 24 hour specs. and then doing the email equivalent of mumbling and pointing the other way when you request the cal cert for the E4419...
But don't let that sway you...