I agree that the 50MHz source needs to be calibrated. I have tow methods of checking:
1) The HP 435 meter (and also the 432) Have references taht are known to be very stable - my first go to reference
2) I have a 732 voltage source and a companion divider. I can calibrate a scope(at DC) and make the assumption that a good plug in will not have significant error at 50MHz (e.g. 7104A with 7A29A).
If both these methods agree, it is reasonable to assume the 50MHz reference is accurate.
I also have an HP 432 and an 8478B for comparison. Kind of an "interesting ensamble" ensemble calibration, but good enough for my needs.
Chers!
Bruce
Quoting Lothar baier <Lothar@...>:
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Normally labs in the industry run 24/7 , even if people work 9-5 there are usually test labs that run tests that often run for days or even weeks HALT/HAST tests usually run for a long time non stop but even in labs that have a regular work schedule nobody actually bothers to turn stuff off when not in use , the recommended calibration intervals are based on this type of use.
Power sensors usually are pretty stable especially if they are not used on a daily basis but 5 years is a bit of a stretch , also consider that in order for the sensor to read accurately your 50MHz reference on your meter has to be within specs , if this one is off so will your readings , people often tend to overlook that the 848x sensors actually do not measure absolute power but the power referenced to the 0dBm calibrator , this is also the reason you can not calibrate the 50MHz reference with a 848x sensor but have to use a 478A and 432A to do this , this is why I send the meter out with my sensor
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of Bruce via groups.io
Sent: Monday, March 7, 2022 8:46 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Scoping the Power Rails [8566B]
I was probably a bit heavy handed and overstated my objection. I have a few "standards" that I maintain. I have a fluke 732 that I compare at a friend of mines metrology lab about once a year, and I have an HP8487A that I have calibrated every 5 years or so. Also have a couple of high precision resistance standards. These devices are ONLY used as reference standards and never used on the bench except for that purpose.
I cannot afford to have something like my 8566s professionally calibrated, but I can (and do) execute the calibration procedure after a repair or if I find anything that does not seem right during use.
Essentially, I agree with you but perhaps with a stricter budget constraint.
Also,my comment was periodic calibration was ridiculous - I should have said periodic calibration on the manufacturer's schedule is a wast of money unless it is required as part of the services you perform.
Cheers!
Bruce
Quoting Lothar baier <Lothar@...>:
Bruce ,
In regards to calibration I care to argue that periodic calibration in
a hobby/home lab environment is not a necessity , I do however see a
benefit in having a initial calibration performed when a piece of
equipment has been acquired or if a repair has been performed , first
of it gives you the certainty that the equipment does not have any
faults and in the case of power sensors for example the updated
calibration factors ensure that you are reading correct power levels
-----Original Message-----
From: [email protected]
<[email protected]> On Behalf Of Bruce via
groups.io
Sent: Monday, March 7, 2022 5:14 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Scoping the Power Rails
[8566B]
Periodic calibration is a ridiculous expense. I am a hobbyist - for
about 30 years :-)
Regarding the 10MHz calibration, it is a good idea to have a 10MHz GPS
based standard - they are not overly expensive and give you at least
one source you can depend on for comparison. Your frequency counter
(at least) should be driven by that reference. Ideally ALL
instruments should be driven from a common 10MHz reference (that is
GPS synched).
SA stands for spectrum analyzer
What I was asking is what diagnostic message appear on the screen.
There is a procedure in the adjustments section of the manual for the
100MHz reference oscillator - you should try following it WITHOUT
performing any adjustments - If you find the PLL voltage excessively
far off,you should probably do the oscillator centering adjustment,
but probably best to let us know the results B4 making the adjustment.
Are you seeing REF UNLOCK or just YTO unlock or what ?
Quoting Jinxie <paul666@...>:
@Bruce
When you say "reported by the SA" do you mean the on-screen messages
which are there during normal operation or some kind of internal
diagnostics procedure I'm unfamiliar with?
The persistent one is "YTO Unlock" - that's just on all the time.
The frequency reference is just the internal one in my Philips 10Ghz
counter which I admit hasn't been calibrated for years - but I'm just
a hobbyist and can't justify the expense of periodic calibration.
