In article , doug doug@doug wrote:
Ken Smith wrote:
In article , doug doug@doug wrote:

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.




--
--
forging knowledge

On Mar 1, 6:18 am, MassiveProng
wrote:
On 28 Feb 2007 21:47:49 -0800, "Too_Many_Tools"
Gave us:



If you have used test gear, and you do not intend to PAY to have it
calibrated, you be best off leaving it all the **** ALONE!

LOL

You're a real ray of sunshine, aren't you?

Now go out and play in traffic while we adults talk about serious
stuff..

TMT

Serious? Look, dumb****, 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. Dumb**** to you MiniPrick....now get to
work. LOL

TMT

In article ,
(known to some as Jim Yanik) scribed...

snippety

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.


--
Dr. Anton T. Squeegee, Director, Dutch Surrealist Plumbing Institute
(Known to some as Bruce Lane, KC7GR)
http://www.bluefeathertech.com -- kyrrin a/t bluefeathertech d-o=t calm
"Salvadore Dali's computer has surreal ports..."

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





On Mar 1, 6:23 am, MassiveProng
wrote:
On 28 Feb 2007 21:50:49 -0800, "Too_Many_Tools"
Gave us:



Thanks for the (positive) comments so far.

I look forward to any more you might want to offer.

Any circuits or examples others have done?

Any cal boxes that anyone have built?

TMT

All the circuits suggested here, while appearing good on the surface,
are all likely to introduce more error into your instruments than
correct.

THAT IS WHY REAL calibration services are used, and why I suggested
that if you do not intend to have it professionally calibrated, you...
YOU IN PARTICULAR, should just leave the gear alone, as you are too
****ing stupid to do it without introducing the aforementioned error.

In other words, they are better off UNcalibrated and still reliable,
than after any futzing around a twit like you will do with them. You
LACK the competence.

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

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





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

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

David L. Jones wrote:
On Mar 1, 5:09 pm, Robert Baer wrote:

David L. Jones wrote:

On Mar 1, 12:27 pm, "Too_Many_Tools" wrote:

I have a well stocked test bench at home containing a range of analog,
digital and RF test equipment as I am sure most of you also do.

Well the question I have is how do you handle the calibration of your
equipment? What do you use for calibration standards for resistance,
voltage, current and frequency?

Links to recommended circuits, pictures and sources would be
appreciated.

Since this is a need for anyone who has test equipment, I hope to see
a good discussion on this subject.

If you've got that sort of gear at home then usually you have better
(and calibrated) gear at work as well, in which case most of us would
simply bring in our gear from home and spot check it against the good
gear.

In the absense of this gear, you can simply use precision components.
Voltage reference chips with 0.05% or better are cheap and readilly
available.
0.01% resistors are available too.

If you have multiple meters for example, you can also keep an eye on
them by comparison. Using any old component, if all three meters read
the same then you can be pretty confident they haven't drifted.

Checking scope horizontal timebases is easy with a crystal oscillator
and divider.

There are various methods for getting an accurate frequency standard,
but one of the newst methods is using a GPS derived reference. Second
hand Rubidium standards can also be had on eBay.

Generally though, good quality test gear does not drift out of spec,
so the need for regular calibration is minimal.

Dave

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

Dave

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

JW wrote:

On 28 Feb 2007 22:45:45 -0800 "David L. Jones" wrote
in Message id: .com:


On Mar 1, 5:09 pm, Robert Baer wrote:


[...]


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/DkSea...S&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???

MassiveProng wrote:

On Thu, 1 Mar 2007 03:50:23 +0000 (UTC), (Ken
Smith) Gave us:


In article m,
Too_Many_Tools wrote:

I have a well stocked test bench at home containing a range of analog,
digital and RF test equipment as I am sure most of you also do.

Well the question I have is how do you handle the calibration of your
equipment? What do you use for calibration standards for resistance,
voltage, current and frequency?

For frequency, you can use WWV. You need:
A short wave radio with an audio output.
Perhaps an audio filter tuned to about 1KHz.
A generator you wish to calibrate near the WWV frequency.
A frequency counter that is not too far off.

Procedu
Tune in WWV.
Put wire on generator and set it to WWV-1KHz
Listen for tone and move stuff around until it sounds good.
Feed tone into the filter.
Place the counter on the output of the filter.

The number on the counter is X Hz away from 1KHz when the generator is XHz
off from WWV-1KHz.



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"?

MassiveProng wrote:

On Thu, 01 Mar 2007 06:09:35 GMT, Robert Baer
Gave us:


David L. Jones wrote:


On Mar 1, 12:27 pm, "Too_Many_Tools" wrote:


I have a well stocked test bench at home containing a range of analog,
digital and RF test equipment as I am sure most of you also do.

Well the question I have is how do you handle the calibration of your
equipment? What do you use for calibration standards for resistance,
voltage, current and frequency?

Links to recommended circuits, pictures and sources would be
appreciated.

Since this is a need for anyone who has test equipment, I hope to see
a good discussion on this subject.


If you've got that sort of gear at home then usually you have better
(and calibrated) gear at work as well, in which case most of us would
simply bring in our gear from home and spot check it against the good
gear.

In the absense of this gear, you can simply use precision components.
Voltage reference chips with 0.05% or better are cheap and readilly
available.
0.01% resistors are available too.

If you have multiple meters for example, you can also keep an eye on
them by comparison. Using any old component, if all three meters read
the same then you can be pretty confident they haven't drifted.

Checking scope horizontal timebases is easy with a crystal oscillator
and divider.

There are various methods for getting an accurate frequency standard,
but one of the newst methods is using a GPS derived reference. Second
hand Rubidium standards can also be had on eBay.

Generally though, good quality test gear does not drift out of spec,
so the need for regular calibration is minimal.

Dave


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.



Or if the order is large enough.
Ahhh yesss....the Golden Rule.

Tim Shoppa wrote:

On Feb 28, 9:27 pm, "Too_Many_Tools" wrote:

I have a well stocked test bench at home containing a range of analog,
digital and RF test equipment as I am sure most of you also do.

Well the question I have is how do you handle the calibration of your
equipment? What do you use for calibration standards for resistance,
voltage, current and frequency?


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!

Jim Yanik wrote:

chuck wrote in
:


Tim Shoppa wrote:

On Feb 28, 9:27 pm, "Too_Many_Tools"
wrote:

I have a well stocked test bench at home containing a range of
analog, digital and RF test equipment as I am sure most of you also
do.

Well the question I have is how do you handle the calibration of
your equipment? What do you use for calibration standards for
resistance, voltage, current and frequency?

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.


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.


A lot of good points have been made already so I'll just add a small
one.

Don't mess with calibration of quality equipment unless you have
reason to believe the calibration is off AND THAT IS ADVERSELY
AFFECTING YOUR WORK PRODUCTS. An amazing amount of electronics work
has been done using equipment with non-current calibration stickers,
some of which was out of calibration.

If metrology is something that interests you as a hobby, then jump
into it and have fun. Tim's last paragraph ought to be printed and
framed.

Chuck


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!

Bud-- wrote:

Ken Smith wrote:

In article m,
Too_Many_Tools wrote:

I have a well stocked test bench at home containing a range of analog,
digital and RF test equipment as I am sure most of you also do.

Well the question I have is how do you handle the calibration of your
equipment? What do you use for calibration standards for resistance,
voltage, current and frequency?



For frequency, you can use WWV. You need:
A short wave radio with an audio output.
Perhaps an audio filter tuned to about 1KHz.
A generator you wish to calibrate near the WWV frequency.
A frequency counter that is not too far off.

Procedu
Tune in WWV.
Put wire on generator and set it to WWV-1KHz
Listen for tone and move stuff around until it sounds good.
Feed tone into the filter.
Place the counter on the output of the filter.

The number on the counter is X Hz away from 1KHz when the generator is
XHz off from WWV-1KHz.


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.

--
bud--

Check.

On Thu, 1 Mar 2007 06:43:01 -0600, "Anthony Fremont"
Gave us:

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

Huh?

I think it would do
fine.

Bwuahahahahahahaha! Hilarious!

On 1 Mar 2007 19:28:47 -0800, "Too_Many_Tools"
Gave us:

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 ****head 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 ****... 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.

On Thu, 1 Mar 2007 19:39:00 +0000, Clint Sharp
Gave us:

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
FPD, and I can setup my stereo sicwith the audio diagnostic and
setup section.

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.

On Mar 2, 6:21 pm, MassiveProng
wrote:
On Thu, 1 Mar 2007 06:43:01 -0600, "Anthony Fremont"
Gave us:

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

Huh?

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

I think it would do
fine.

Bwuahahahahahahaha! Hilarious!

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

Dave

On 1 Mar 2007 19:22:16 -0800, "Too_Many_Tools"
Gave us:

And oh yeah....that's Mr. Dumb****


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 ****.

There is no backwoods calibration of perfectly good gear. All there
is is some hillbilly ****tard like you ****ing 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.

On Thu, 01 Mar 2007 16:32:18 -0600, clifto Gave us:

Bud-- wrote:
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.

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!

On 1 Mar 2007 23:53:14 -0800, "David L. Jones"
Gave us:

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.

On 1 Mar 2007 23:53:14 -0800, "David L. Jones"
Gave us:


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, dip****.

MassiveProng wrote:
On Thu, 1 Mar 2007 06:43:01 -0600, "Anthony Fremont"
Gave us:

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

Huh?

Yeah, maybe you should do some reading.

I think it would do
fine.

Bwuahahahahahahaha! Hilarious!

On Fri, 02 Mar 2007 05:38:04 GMT Robert Baer
wrote in Message id:
. net:

JW wrote:

On 28 Feb 2007 22:45:45 -0800 "David L. Jones" wrote
in Message id: .com:


On Mar 1, 5:09 pm, Robert Baer wrote:


[...]


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/DkSea...S&Cat=34342147
"Your search criteria has expired"

I hate it when that happens...

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???

Put .01% into the search box and you'll get a link to the .01% resistors.
For quantity 1 they are 5-6 bucks apiece.

Or maybe this link will work if it doesn't expire, that is:
http://www.digikey.com/scripts/DkSea...S&Cat=34342147

On Mar 1, 10:40 am, Jim Yanik wrote:
chuck wrote :





Tim Shoppa wrote:
On Feb 28, 9:27 pm, "Too_Many_Tools"
wrote:
I have a well stocked test bench at home containing a range of
analog, digital and RF test equipment as I am sure most of you also
do.

Well the question I have is how do you handle the calibration of
your equipment? What do you use for calibration standards for
resistance, voltage, current and frequency?

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.

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.







A lot of good points have been made already so I'll just add a small
one.

Don't mess with calibration of quality equipment unless you have
reason to believe the calibration is off AND THAT IS ADVERSELY
AFFECTING YOUR WORK PRODUCTS. An amazing amount of electronics work
has been done using equipment with non-current calibration stickers,
some of which was out of calibration.

If metrology is something that interests you as a hobby, then jump
into it and have fun. Tim's last paragraph ought to be printed and
framed.

Chuck

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.

--
Jim Yanik
jyanik
at
kua.net- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

I just got done calibrating a AM503 & A6302 current probe / amp
somebody took a screwdriver to. Without the manual and all required
gear (PG506), and cal fixtures it would never have worked properly
again. I work in a cal lab and the best part about iso9002 was
requiring the sealing stickers (cal void if seal is broken). We never
used them prior to iso certification.

On Mar 2, 6:57 am, "carneyke" wrote:
On Mar 1, 10:40 am, Jim Yanik wrote:





chuck wrote :

Tim Shoppa wrote:
On Feb 28, 9:27 pm, "Too_Many_Tools"
wrote:
I have a well stocked test bench at home containing a range of
analog, digital and RF test equipment as I am sure most of you also
do.

Well the question I have is how do you handle the calibration of
your equipment? What do you use for calibration standards for
resistance, voltage, current and frequency?

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.

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.

A lot of good points have been made already so I'll just add a small
one.

Don't mess with calibration of quality equipment unless you have
reason to believe the calibration is off AND THAT IS ADVERSELY
AFFECTING YOUR WORK PRODUCTS. An amazing amount of electronics work
has been done using equipment with non-current calibration stickers,
some of which was out of calibration.

If metrology is something that interests you as a hobby, then jump
into it and have fun. Tim's last paragraph ought to be printed and
framed.

Chuck

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.

--
Jim Yanik
jyanik
at
kua.net- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

I just got done calibrating a AM503 & A6302 current probe / amp
somebody took a screwdriver to. Without the manual and all required
gear (PG506), and cal fixtures it would never have worked properly
again. I work in a cal lab and the best part about iso9002 was
requiring the sealing stickers (cal void if seal is broken). We never
used them prior to iso certification.- Hide quoted text -

- Show quoted text -

Forgot to mention : If you want to cal your own gear, mark any pots /
vari-caps and write down any software codes BEFORE changing. Do not
adjust the compensation capacitors in any Tektronix attenuators
without a PG506 and a procedure.

Jim Yanik - This note isn't for you, as you have seen the damage
too.....

In message , MassiveProng
writes
On Thu, 1 Mar 2007 19:39:00 +0000, Clint Sharp
Gave us:

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.
So varying the reference clock of a DVD player doesn't affect the pitch
of any tones played back off a disk? OK. I wondered because it does on a
CD player.

It carries DTS and THX certified content.
K, so it's a good for setting up home theatre equipment at the very
least

That is the current reference standard for MPEG, if you know who
they are.
Not personally, but I may have heard of them in passing.
That's good enough for me. I can verify the setup of my
FPD,
FPD?
and I can setup my stereo sicwith the audio diagnostic and
setup section.


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!
Hey 'pal' I didn't try to change the scenario, I just speculated that a
GPS source would be better.
A subsequent poster mentioned a GPS setup.
Go back and read.
No need, I read that post, that's why I mentioned it. Turn down the
aggression a notch or two, I only asked a question and speculated that
there might be a better way.
--
Clint Sharp

On Mar 2, 1:46 am, MassiveProng
wrote:
On 1 Mar 2007 19:28:47 -0800, "Too_Many_Tools"
Gave us:

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 ****head 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 ****... 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.

So it sounds like you are having a problem finding two brain cells
MiniPrick...try harder.

No more of your excuses....SHOW us how great you are.

Laugh...laugh...laugh....

TMT

On Mar 2, 7:32 pm, MassiveProng
wrote:
On 1 Mar 2007 23:53:14 -0800, "David L. Jones"
Gave us:



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, dip****.

Not in this case.
If he used a meter with 0.5% accuracy on DC volts then he could check
and adjust his scope's vertical scale to the same 0.5% accuracy.

And if you start crapping on about the tolerance of the resistor chain
adding up etc, then you haven't thought about this one hard enough...

Dave

On Mar 2, 7:31 pm, MassiveProng
wrote:
On 1 Mar 2007 23:53:14 -0800, "David L. Jones"
Gave us:

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.

My 6000 series Agilent is not behind the times, and it's only +/-2%
accurate on the vertical scale.
A good analog scope like say the Tek2465 is only 2% as well.

Perhaps those two are the exception huh? Care to post some links to
prove otherwise?
I could post until the cows come home scopes that are no better than a
few % accurate on the vertical scale.

Dave

On Fri, 2 Mar 2007 18:19:08 +0000, Clint Sharp
Gave us:

That's good enough for me. I can verify the setup of my
FPD,
FPD?


Flat Panel Display.

You ain't too sharp, Sharp.

On Fri, 2 Mar 2007 18:19:08 +0000, Clint Sharp
Gave us:

the scene, pal!
Hey 'pal' I didn't try to change the scenario, I just speculated that a
GPS source would be better.


There's no doubt it would be better for RF frequency locks. Since we
use them at work, I have no doubts about their capabilities.

Audio though? Most of the respondents referred to audio spectrum
frequencies.

On 2 Mar 2007 13:06:24 -0800, "David L. Jones"
Gave us:

On Mar 2, 7:32 pm, MassiveProng
wrote:
On 1 Mar 2007 23:53:14 -0800, "David L. Jones"
Gave us:



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, dip****.

Not in this case.
If he used a meter with 0.5% accuracy on DC volts then he could check
and adjust his scope's vertical scale to the same 0.5% accuracy.

And if you start crapping on about the tolerance of the resistor chain
adding up etc, then you haven't thought about this one hard enough...


If you set a scope up with 0.5% accurate source validator, the scope
will NOT have that accuracy level. It will ONLY have that accuracy
level at that set point, and that is even questionable.

In message , MassiveProng
writes
On Fri, 2 Mar 2007 18:19:08 +0000, Clint Sharp
Gave us:

That's good enough for me. I can verify the setup of my
FPD,
FPD?


Flat Panel Display.

You ain't too sharp, Sharp.
Ahh, so you're recommending calibrating test equipment using the same
DVD as you use to set up your boob tube. Explains a lot.
--
Clint Sharp

On Mar 3, 9:30 am, MassiveProng
wrote:
On 2 Mar 2007 13:06:24 -0800, "David L. Jones"
Gave us:



On Mar 2, 7:32 pm, MassiveProng
wrote:
On 1 Mar 2007 23:53:14 -0800, "David L. Jones"
Gave us:

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, dip****.

Not in this case.
If he used a meter with 0.5% accuracy on DC volts then he could check
and adjust his scope's vertical scale to the same 0.5% accuracy.

And if you start crapping on about the tolerance of the resistor chain
adding up etc, then you haven't thought about this one hard enough...

If you set a scope up with 0.5% accurate source validator, the scope
will NOT have that accuracy level. It will ONLY have that accuracy
level at that set point, and that is even questionable.

Which is why you do it for each range and then spot check it to see
that there is no funny business. Perfectly valid technique for home
calibration of a scope vertical scale.

Dave

"David L. Jones" wrote in
ups.com:

On Mar 2, 7:31 pm, MassiveProng
wrote:
On 1 Mar 2007 23:53:14 -0800, "David L. Jones"
Gave us:

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.

My 6000 series Agilent is not behind the times, and it's only +/-2%
accurate on the vertical scale.
A good analog scope like say the Tek2465 is only 2% as well.

Better look again;IIRC,it's 1.25% . That does not include the cursors.

It's not really significant,as you can't get that resolution on the screen.


--
Jim Yanik
jyanik
at
kua.net

Robert Baer wrote:
JW wrote:

On 28 Feb 2007 22:45:45 -0800 "David L. Jones" wrote
in Message id: .com:


On Mar 1, 5:09 pm, Robert Baer wrote:



[...]


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/DkSea...S&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???


Try DigiKey Part # MR102-100-.01-ND

Ed

Too_Many_Tools wrote:
I have a well stocked test bench at home containing a range of analog,
digital and RF test equipment as I am sure most of you also do.

Well the question I have is how do you handle the calibration of your
equipment? What do you use for calibration standards for resistance,
voltage, current and frequency?

Links to recommended circuits, pictures and sources would be
appreciated.

Since this is a need for anyone who has test equipment, I hope to see
a good discussion on this subject.

Thanks

TMT


The real question is how much precision do you
really need in the home "lab"? How often have
you needed to use your DMM with how many
*accurate* significant digits? 100 minus some
*very* small percent of the time, 2 significant
digits is all you need. Do you _really_ care
if your 5.055 volt reading is really 5.06 or 5.04?

Oh hell yes, I want to puff out my chest like everyone
else and think I have *accurate* equipment.

But I'm curious as to what home circuits need meters
that can read voltage accurately to 3 decimal places?
2 decimal places? The question for current measurement:
in what home brew circuit design/troubleshooting do you
need accuracy below the tens of mA digit ? *Need*, not
*want*. Do you even trust your DMM on an amps setting
for those measurements, or do you measure the current
indirectly? How about ohms? Would you trust any
DMM, regardless of who calibrated it, to measure
down in the miliohm numbers?

To me, the design of the circuit being mesured has
to take care of all of that crap. If it is so
poorly designed that a 10 mV departure from nominal
(that is missed by my innaccurate meter) will keep
it from working, that suggests other problems.
Yes, the home "lab" person wants extreme accuracy
to as many decimal places as he can get. But when does
he ever really need it?

None of this is to argue against having the best
instrumentation you can afford, or references to
check it against, or paying for calibration and so
forth. But for myself, I need a dose of reality
from time to time when I start drooling over some
accuracy specs that I will never need at home. My
bet is that most of us are seduced by that same muse.

Ed

ehsjr wrote:
Too_Many_Tools wrote:
I have a well stocked test bench at home containing a range of
analog, digital and RF test equipment as I am sure most of you also
do. Well the question I have is how do you handle the calibration of your
equipment? What do you use for calibration standards for resistance,
voltage, current and frequency?

Links to recommended circuits, pictures and sources would be
appreciated.

Since this is a need for anyone who has test equipment, I hope to see
a good discussion on this subject.

Thanks

TMT


The real question is how much precision do you
really need in the home "lab"? How often have
you needed to use your DMM with how many
*accurate* significant digits? 100 minus some
*very* small percent of the time, 2 significant
digits is all you need. Do you _really_ care
if your 5.055 volt reading is really 5.06 or 5.04?

Oh hell yes, I want to puff out my chest like everyone
else and think I have *accurate* equipment.

But I'm curious as to what home circuits need meters
that can read voltage accurately to 3 decimal places?
2 decimal places? The question for current measurement:
in what home brew circuit design/troubleshooting do you
need accuracy below the tens of mA digit ? *Need*, not

You surely didn't mean tens of _mA_, did you? I build stuff with PICs as
you know, and some of it is designed to run on batteries and needs to go for
long periods of time unattended. The current draw for a 12F683 running at
31kHz is 11uA, sleep current is 50nA. If I could only measure current to
"tens of mA", I'd never know if the PIC was setup right for low current draw
and I certainly couldn't have any idea of expected battery life. I wouldn't
even know if it was sleeping until it ate thru some batteries in a few days
instead of six or eight months. I think I have a need to measure fractions
of a uA.

*want*. Do you even trust your DMM on an amps setting
for those measurements, or do you measure the current
indirectly? How about ohms? Would you trust any
DMM, regardless of who calibrated it, to measure
down in the miliohm numbers?

To me, the design of the circuit being mesured has
to take care of all of that crap. If it is so
poorly designed that a 10 mV departure from nominal
(that is missed by my innaccurate meter) will keep
it from working, that suggests other problems.
Yes, the home "lab" person wants extreme accuracy
to as many decimal places as he can get. But when does
he ever really need it?

When he needs it he needs it, what can I say? Do I really "need" a new DSO?
Well I've managed to get by all this time without one, so maybe you think I
don't really "need" one. I see it like this though, I don't get allot of
time to tinker anymore. I'd like to spend it more productively. Instead of
fumbling around and trying to devise silly methods to make my existing
equipment do something it wasn't designed to (like going off on a tangent to
build a PIC circuit that will trigger my scope early so I can try to see
some pre-trigger history).

None of this is to argue against having the best
instrumentation you can afford, or references to
check it against, or paying for calibration and so

I don't know if I really agree with that. ;-)

forth. But for myself, I need a dose of reality
from time to time when I start drooling over some
accuracy specs that I will never need at home. My
bet is that most of us are seduced by that same muse.

Ed

On Fri, 2 Mar 2007 23:06:13 +0000, Clint Sharp
Gave us:

In message , MassiveProng
writes
On Fri, 2 Mar 2007 18:19:08 +0000, Clint Sharp
Gave us:

That's good enough for me. I can verify the setup of my
FPD,
FPD?


Flat Panel Display.

You ain't too sharp, Sharp.
Ahh, so you're recommending calibrating test equipment using the same
DVD as you use to set up your boob tube. Explains a lot.

No, dip****. I recommended an industry standard source, and I don't
"set-up" my boob tube you brainless twit, I CHECK its setup, and use
the disc to actually set-up my home audio system.

This ain't the days of the sixties where you get to tweak a bunch of
pots.

Stop being so think.

In message , MassiveProng
writes
No, dip****. I recommended an industry standard source,
To calibrate test gear. As specified in the original post.
and I don't
"set-up" my boob tube you brainless twit,
So you don't know how to access the service menu and make changes to the
setup of your boob tube. Fair enough, I thought someone as knowledgeable
as you would know how to do that but I guess I was wrong.
I CHECK its setup, and use
the disc to actually set-up my home audio system.
Good for you, please explain how the OP was going to use a DVD to
calibrate his test equipment.

This ain't the days of the sixties where you get to tweak a bunch of
pots.
No, you don't, all the adjustments are done via menu now.

Stop being so think.
I think, you just rant. Please get it right. Maybe you could use that
DVD to calibrate your anger response, maybe you could eBay it and your
home audio system to pay for some anger management?
--
Clint Sharp

Good comments Ed.

I want to thank everyone else who has offered *positive* comments
also.

Like I said, I think this is a need for anyone who has equipment at
home.

TMT


On Mar 2, 11:22 pm, ehsjr wrote:
Too_Many_Tools wrote:
I have a well stocked test bench at home containing a range of analog,
digital and RF test equipment as I am sure most of you also do.

Well the question I have is how do you handle the calibration of your
equipment? What do you use for calibration standards for resistance,
voltage, current and frequency?

Links to recommended circuits, pictures and sources would be
appreciated.

Since this is a need for anyone who has test equipment, I hope to see
a good discussion on this subject.

Thanks

TMT

The real question is how much precision do you
really need in the home "lab"? How often have
you needed to use your DMM with how many
*accurate* significant digits? 100 minus some
*very* small percent of the time, 2 significant
digits is all you need. Do you _really_ care
if your 5.055 volt reading is really 5.06 or 5.04?

Oh hell yes, I want to puff out my chest like everyone
else and think I have *accurate* equipment.

But I'm curious as to what home circuits need meters
that can read voltage accurately to 3 decimal places?
2 decimal places? The question for current measurement:
in what home brew circuit design/troubleshooting do you
need accuracy below the tens of mA digit ? *Need*, not
*want*. Do you even trust your DMM on an amps setting
for those measurements, or do you measure the current
indirectly? How about ohms? Would you trust any
DMM, regardless of who calibrated it, to measure
down in the miliohm numbers?

To me, the design of the circuit being mesured has
to take care of all of that crap. If it is so
poorly designed that a 10 mV departure from nominal
(that is missed by my innaccurate meter) will keep
it from working, that suggests other problems.
Yes, the home "lab" person wants extreme accuracy
to as many decimal places as he can get. But when does
he ever really need it?

None of this is to argue against having the best
instrumentation you can afford, or references to
check it against, or paying for calibration and so
forth. But for myself, I need a dose of reality
from time to time when I start drooling over some
accuracy specs that I will never need at home. My
bet is that most of us are seduced by that same muse.

Ed- Hide quoted text -

- Show quoted text -

On 2 Mar 2007 15:09:30 -0800, "David L. Jones"
Gave us:

Which is why you do it for each range and then spot check it to see
that there is no funny business. Perfectly valid technique for home
calibration of a scope vertical scale.

Dave

It doesn't matter how many "places" you "spot check" it, you are not
going to get the accuracy of your comparison standard on the device
you intend to set with it. What you do is take the basic INaccuracy
of the device needing to be set, and add to it the basic INaccuracy of
the standard to which you are setting it. You CANNOT get any closer
than that. So, a 0.5% meter, and a 0.5% scope cannot be used together
to make the scope that accurate. You need a *finer* standard than the
accuracy level you wish to achieve.

You need to understand that as a basic fact, chucko.