Calibration Of Electronic Equipment In The Home Workshop

[Ken Smith]

A mistake go read it if you want.

No. One part in 100 million (10^-8) is 100 times

Yes, I misread the statement.

[....]

uncompensated or poorly compensated timebases are basically useless for
any serious work.

That depends a lot on your definition of "serious". There are lots of
things where just being within 100PPM is more than good enough. RS232 is
ok up to 5% error. If the so called 60Hz in your motor home was actually
59.9Hz, I don't think you would mind.

The other nice part about the high stability
references is that you can distribute it to all the synthesizers on your
bench and everything is coherent.
Of course it depends on what you do. For my ham work, one ppm is fine.
I do other work where the Rb source is not good enough.

A lot of them have worse short term noise than a good OCXO.

 

[Too_Many_Tools]

Serious? Look, dumbfuck, if you are concerned with calibration,
then you should be concerned enough to do it right. Asking here the
way you did means that you are beyond your depth to start with.

If you are too stupid to take your device to a place where freshly
calibrated devices are, and check it against them, you are too stupid
to be attempting to do it with some patched up method in the home
without cal manuals from the makers of all those devices. Far too
stupid.

So **** you, pops.

You prove that numeric age does not an adult make. The traffic I
play in runs at 30GHz, so you are screwed with that presumption as
well. I had calibrated meters back in 1970, and knew more then than
you do know.

Damn...you back already? Well I guess the traffic was light today.

Well MiniPrick since you are here taking up bytes, why don't you prove
to us how really brilliant you are?

Why don't you rub both of your brain cells together and come up with a
setup that a home lab can use for general cal purposes? You ARE smart
enough to do that, aren't you? Don't disappoint all of us now....we
are waiting....so either put up or shut up "Genius".

And oh yeah....that's Mr. Dumbfuck to you MiniPrick....now get to
work. LOL

TMT

 

[Dr. Anton T. Squeegee]

www.tegam.com

Unfortunately, according to their product list, they have
discontinued ALL their O-Scope calibration products.

However, that's not necessarily the end of the world, as it were.
This simply means that there is a better chance of such showing up on
the surplus market, which consequently creates a much better chance of
my finding something useful. ;-)

Thanks.

 

[Too_Many_Tools]

You want to attack my adulthood, fine, little boy. You are
BRAINLESS for this task.

I wasn't attacking your adulthood MiniPrick....an adult would not
behave in the manner you are.

Now a child....yes a child could easily be acting this way....so from
now on we will call you MiniPrick.

I have worked in cal labs and in QA for years. You lose, sonny.

Laugh....laugh....laugh....emptying trash cans is NOT working in cal
labs and QA.

Hey MiniPrick....you done with the homework assignment yet?

TMT

 

[Robert Baer]

Not so.
RS Components have 0.01% resistors for AU$34.50 (US$26)
Farnell have 0.02% for as little as AU$20

Dave

You guys outside the US ahve it soooo good!
Here in the US, it is like i mentioned.

 

[Robert Baer]

[...]

True, 0.01% resistors are available, *but* they are extremely
expensive (over $100 each) and they are made when and if the
manufacturer sees fit to do so.

Not so.
RS Components have 0.01% resistors for AU$34.50 (US$26)
Farnell have 0.02% for as little as AU$20

You guys are paying *way* too much. We use Riedon .01% precision resistors
in our A/D products, and pay about 5 bucks apiece. Their site is down at
the moment, but even Digikey has .01% resistors for around the same price:
http://www.digikey.com/scripts/DkSearch/dksus.dll?Criteria?Ref=3107&Site=US&Cat=34342147

"Your search criteria has expired"
Furthermore a search on "34342147" (no quotes) gets zero matches.
A search on "3107" (no quotes) gets matches that are not better than 1%.
Strangely enough, a search on "precision resistors" (no quotes_ is as
bad.
Worse, a search for "resistors" and wading thru the various types
gets *at best* Chip Resistor-Thin Film(67311 items) with 0.02% as the
best or tolerance listed.
So......
Where are those mysterious 0.01% resistors???

 

[Robert Baer]

Joe Kane's audio video set up discs on Laser Disc, and DVD, and now
HD DVD are the bee's knees for a lot of audio spectrum sine wave
tones.

DVD $20, Player $40 TV and Audio gear already owned.

Catching it off some transmission has to be far more inaccurate.
Short wave receiver worth having $100 plus. Then add in audio gear?

Catching you thinking old is better than new after your brow beating
of BAH... priceless.

Hehehe... just kidding...

"Bee's Knees"?? Was that before or after the "Cat's pajamas"?

 

[Robert Baer]

Or if the order is large enough.

Ahhh yesss....the Golden Rule.

 

[Robert Baer]

It depends entirely on what you need the equipment for.

If for any legal reason you need NBS traceability, then the question
of how and how often is already answered by your regulatory agencies.

If you don't, then I cannot imagine that a couple off-the-shelf
precision resistors, voltage references, and frequency references
(total cost: $10) would not be good enough for sanity checking for
almost any pedestrian uses.

If you're the sort who keeps equipment on your bench just to calibrate
equipment on your bench just to calibrate equipment on your bench,
then any rational argument about traceability is pointless because
you've already set yourself up in an infinite circular loop.

Tim.

Exactly and completely correct in all aspects.
I made a 0.1% resistance reference box: 100 ohms, 1K, 10K, 100K, 1M,
10M and 100M that has been invaluable.
I made a voltage reference box using an Intersil (was Xicor) 5V FGA
reference powered by a 9V battery; good for source and sink and that
initial accuracy of 0.5mV was hard to beat; my HP 5326B verifies the
value within its accuracy as well as the 0.5mV of the reference; both in
the same region of fuzziness - so not too bad.
My handheld DVMs are "fair"; actually the 3.5 digit one os more
stable and reliable in readings than the 4.5 digit.
That one can be set by only one pot which either makes the resistor
readings within spec or makes the DC readings in spec - but not both; i
opted for DC reading accuracy.
I hate it when i have to fiddle with what seems to be a perfectly
good meter, just to make it read correctly (based on two other references).
One of these daze, i may be rich enough to get a Fluke 88845A; and if
*really* rich, will pay for a traceable meter!

 

[Robert Baer]

reminds me of the local TV station techs who insisted that the video gear
of theirs I serviced and calibrated was off,and it turned out their 75 Ohm
termination was 87ohms.Other techs double-terminated monitors and
complained of low brightness,tried to tweak it in,screwed it all up.
Or they would have a "reference" generator at the end of 100's of feet of
coax and complain it was a few percent off.




this is good advice,because without a service manual and cal procedure,you
have no way of knowing what adjustments INTERACT with others.
Adjust a power supply,and gain and timing goes out the window.
Freq.response tweaks can affect more than one area of the signal.


for example,
TEK 475s have multiple vertical gain adjustments,and different adjustments
for the 2/5-10mv ranges.And the gain affects F-response.

Some TV stations had so much RFI that even a VOM had trouble reading
properly on any scale!

 

[Robert Baer]

I believe the color subcarrier in a color TV is phase locked to the
transmitted signal and, for network studio transmissions, is derived
from a cesium clock. From what I have read it is more accurate than WWV
and doesn't require extra equipment other than a TV displaying an image
with a studio source. Frequency is 3.579545 MHz.

Check.

 

[MassiveProng]

Since 3% accuracy is considered good in the scope world,
Huh?

I think it would do
fine.

Bwuahahahahahahaha! Hilarious!

 

[MassiveProng]

Laugh....laugh....laugh....emptying trash cans is NOT working in cal
labs and QA.

Said the utter retard that needed to ask in a BASIC electronics
groups about something which he should already know if he planned to
attempt such a procedure.

Nice try, retard boy. Too bad you are wrong.... again.

Hey MiniPrick....you done with the homework assignment yet?

That of calling you the retarded fuckhead that you are? Sure...
done.

TMT, the total Usenet retard

Yep... that'd be you. Your nym is more correct than you'll ever
know. You're a jack-of-no-trades.

You're a real piece of shit... errr... work, there, bub.

My first advice was spot on. To make a proper cal, the source has
to be ten times better than the accuracy you wish to claim for the
instrument.

NONE of the circuits given in this thread are good enough. ALL of
those IC chips drift with T so much that calling them a cal source is
ludicrous. So are you if you think I don't now quality assurance, and
proper procedure.

You ain't it.

 

[MassiveProng]

Aren't you reliant on the stability of the DVD player reference clock
for the stability of the test tones?

For audio? absolutely. It had nothing to do with the DVD player's
clock. There are several industry standard tones provided, and the
disc replaced hardware TV test generators for years.

It carries DTS and THX certified content.

That is the current reference standard for MPEG, if you know who
they are. That's good enough for me. I can verify the setup of my

I would suspect a GPS reference
would be considerably better. Of course, I could be wrong!

Hey, chucko! He didn't give a GPS source. You don't get to change
the scene, pal! A subsequent poster mentioned a GPS setup.

Go back and read.

 

[David L. Jones]

Huh?

Yep, didn't you know that scope you are using is only a few % accurate
on the vertical scale?

Bwuahahahahahahaha! Hilarious!

Hardly, it would be perfectly adequate for the job actually.

Dave

 

[MassiveProng]

And oh yeah....that's Mr. Dumbfuck

You're an idiot. You're busted.

Proven beyond your depth.

You are too stupid to even know that if you DID make a cal source
device, you would have to get it calibrated to make it worth a shit.

There is no backwoods calibration of perfectly good gear. All there
is is some hillbilly fucktard like you fucking up what was once
perfectly good gear by thinking you have one tenth the brains you need
to do such a chore correctly. You do not.

So **** off.

 

[MassiveProng]

I've seen that discussed elsewhere, and although it would take me a week
to find the particulars, (1) the frequency can be off as much as 10 Hz
by FCC standards, (2) from what I've read it's frequently off by more
than that, even on network feeds, (3) IIRC they don't even use the good
clocks on the networks any more, (4) NIST clocks are going to be a couple
of orders of magnitude better than the best a network would buy for the
purpose of meeting FCC regulations, (5) IIRC the frequency should
actually be 3,579,545.454545454545..... Hz, and (6) Doppler shift on
the incoming television signal could potentially cause the subcarrier
frequency to vary up and down.

So there!

 

[MassiveProng]

Yep, didn't you know that scope you are using is only a few % accurate
on the vertical scale?

You guys must be behind the times.

 

[MassiveProng]

Hardly, it would be perfectly adequate for the job actually.

Wrong. That could easily leave the scope over 6% off.

It takes a much finer source to calibrate a device than the final
accuracy of the device being calibrated, dipshit.

 

[Anthony Fremont]

Huh?

Yeah, maybe you should do some reading.