FS: ROHDE & SCHWARZ ADS-B1 Waveform Generator

[Randy Nachtrieb]

For Sale:
ROHDE & SCHWARZ ADS Dual Arbitrary Waveform Generator(DC-25MHz); w/B1
Clock Generator Option

Both Channels Fully Independently Programmable

Low Distortion Sine & Traingle Waveforms

64K Memory Depth per Channel

12-Bit Resolution

Includes Manual etc.

Excellent Condition; New Price $6000
PRICE: $1895

Please E-mail or call (323)851-8844
Randy Nachtrieb

 

[Jeremy D. Grotte]

I just tried out my 'new' Tek 2246 that I got from ebay. Didn't come with
any probes so I had to find some. Thanks to the guy that gave me the link
to ProbeMaster. Looks like they're good probes, cost enough though! Ya get
what ya pay for.
Anyways, just went thru and cal'd the probes, and just generally checking
out the scope. All of the functions work fine, I fired it up, let it run
for about 1/2 hour, let it run thru it's self-cal. Voltage measurements all
seem to be right on the money since each of those match 2 other meters I've
got down to a couple decimals.
That I double-checked the probes calibration and checked out the cursors.
When I do the probe cal, it shoots out a .5v 1khz pulse. I got the reading
on the scope all nice and square like the book says, but the cursors say
that I've got 1050hz instead of 1000hz. Both of my meters say it's 1050hz,
I ran a 1khz test tone thru the o-scope generated from my PC and the scope
says it's 1050hz. So, from this I can deduce that either the time base is
50hz off at 1khz or my cursors are off 50hz at 1khz, either way it looks
like the scope's time base is off by 5%.

I've got numerous ways of generating an accurate time base, at least much
more accurate than 5% (crystals, ovens, etc), here in the lab, and a few
ways of cross-checking (one being the other 2 meters that say the output is
1000hz whereas the scope says it's 1050hz).

Question is...how do I go about adjusting my scope to match? Any simple
answers to this? It wouldn't be as simple as a single pot to turn in or out
would it?
JDG

 

[Jeremy D. Grotte]

I forgot to mention.
It's a Tektronix 2246 MOD A, Ser# B102449.

"Jeremy D. Grotte" <jdgrotte@ndak.net> wrote in message
news:vlj79u1ttrr0aa@corp.supernews.com...

I just tried out my 'new' Tek 2246 that I got from ebay. Didn't come with
any probes so I had to find some. Thanks to the guy that gave me the link
to ProbeMaster. Looks like they're good probes, cost enough though! Ya
get
what ya pay for.
Anyways, just went thru and cal'd the probes, and just generally checking
out the scope. All of the functions work fine, I fired it up, let it run
for about 1/2 hour, let it run thru it's self-cal. Voltage measurements
all
seem to be right on the money since each of those match 2 other meters
I've
got down to a couple decimals.
That I double-checked the probes calibration and checked out the cursors.
When I do the probe cal, it shoots out a .5v 1khz pulse. I got the
reading
on the scope all nice and square like the book says, but the cursors say
that I've got 1050hz instead of 1000hz. Both of my meters say it's
1050hz,
I ran a 1khz test tone thru the o-scope generated from my PC and the scope
says it's 1050hz. So, from this I can deduce that either the time base is
50hz off at 1khz or my cursors are off 50hz at 1khz, either way it looks
like the scope's time base is off by 5%.

I've got numerous ways of generating an accurate time base, at least much
more accurate than 5% (crystals, ovens, etc), here in the lab, and a few
ways of cross-checking (one being the other 2 meters that say the output
is
1000hz whereas the scope says it's 1050hz).

Question is...how do I go about adjusting my scope to match? Any simple
answers to this? It wouldn't be as simple as a single pot to turn in or
out
would it?
JDG

 

[Jeremy D. Grotte]

I found a manual online a few hours after I posted the message.
If I take the accuracy of the time-base (1/2 digit + 2% of scale) and ADD in
the accuracy of the cursors (1/2 digit + 2% of scale), then I'm still barely
within tolerance.
Guess I'll have to look around for a service manual.
Otherwise, I'll just remember to subtract 5% from the readings! I think
that's worth the $$$ it would cost to get it cal'd.
JDG

"Jim Yanik" <jyanik@abuse.gov> wrote in message
news:Xns93EE828A41842jyanikkuanet@204.117.192.21...

"Jeremy D. Grotte" <jdgrotte@ndak.net> wrote in
news:vlj79u1ttrr0aa@corp.supernews.com:

I just tried out my 'new' Tek 2246 that I got from ebay. Didn't come
with any probes so I had to find some. Thanks to the guy that gave me
the link to ProbeMaster. Looks like they're good probes, cost enough
though! Ya get what ya pay for.
Anyways, just went thru and cal'd the probes, and just generally
checking out the scope. All of the functions work fine, I fired it
up, let it run for about 1/2 hour, let it run thru it's self-cal.
Voltage measurements all seem to be right on the money since each of
those match 2 other meters I've got down to a couple decimals.
That I double-checked the probes calibration and checked out the
cursors. When I do the probe cal, it shoots out a .5v 1khz pulse. I
got the reading on the scope all nice and square like the book says,
but the cursors say that I've got 1050hz instead of 1000hz. Both of
my meters say it's 1050hz, I ran a 1khz test tone thru the o-scope
generated from my PC and the scope says it's 1050hz. So, from this I
can deduce that either the time base is 50hz off at 1khz or my cursors
are off 50hz at 1khz, either way it looks like the scope's time base
is off by 5%.

I've got numerous ways of generating an accurate time base, at least
much more accurate than 5% (crystals, ovens, etc), here in the lab,
and a few ways of cross-checking (one being the other 2 meters that
say the output is 1000hz whereas the scope says it's 1050hz).

Question is...how do I go about adjusting my scope to match? Any
simple answers to this? It wouldn't be as simple as a single pot to
turn in or out would it?
JDG



No,you're going to need a service manual cal procedure(which I don't
have,btw.),and the magnified adjustments are tough without the TEK CG551
calibration generator.Perhaps a Wavetek 9100 series calibrator can do it
too,I'm not certain,though.

BTW,check the specs on cursor measurements,they aren't as accurate as they
can resolve.Definitely not counter accurate.And most TEK scope calibrators
are not very accurate,either,they're intended for probe comp and probe
amplitude checks.A few models did have freq. accurate calibrators,2445/65
series,and a 7704A modified product.

--
Jim Yanik,NRA member
jyanik@kua.net