Date   
Re: BFOs [semi OT]

Chuck Harris
 

I certainly cannot answer that. The BFO you have
is intended for use with a B&K receiver.

Any SWL receiver with a bfo should be adequate to
listen to his signal generator's output.

Why should he do that?

Well, just because a generator puts out a frequency
that is on average the right frequency, doesn't mean
that short therm it is right.

For example. I used to have a wavetek synthesized
signal generator, a 3001, if I recall correctly. It
showed on an oscilloscope a nice looking sine wave,
and showed on a frequency counter a stable frequency,
but if you listened to the signal on a receiver with
a BFO, it sounded like a bird nightmare.

Trying a "similar" sythesizer, a Constron 7100, gave
an nice sweet pure tone.

It is all in the phase noise.

-Chuck Harris

John Griessen wrote:

"Do you have any HF receivers around that you can use to
listen to the output of your signal generator at 1, 2, 3,
4... MHz, with a BFO?

I have a feeling it will sound like a aviary full of
birds.

-Chuck Harris"

What kind of receivers and amps that are not too large would be useful along with a BFO
to check for unwanted RF emitted by microcontroller boards and switching power supplies?
I have a Bruel and Kjaer 1022 BFO, and am thinking maybe I could rig an input to use
instead of
the built in one. No manual though. Still worked great the last time I asked it to
wobbulate...

BFOs [semi OT]

John Griessen
 

"Do you have any HF receivers around that you can use to
listen to the output of your signal generator at 1, 2, 3,
4... MHz, with a BFO?

I have a feeling it will sound like a aviary full of
birds.

-Chuck Harris"

What kind of receivers and amps that are not too large would be useful along with a BFO
to check for unwanted RF emitted by microcontroller boards and switching power supplies?
I have a Bruel and Kjaer 1022 BFO, and am thinking maybe I could rig an input to use instead of
the built in one. No manual though. Still worked great the last time I asked it to wobbulate...

Re: Beam modulation on 2465B

Chuck Harris
 

That is an awfully sharp response. What happens when you
turn the readout back on?

I have seen some weird screen displays caused by the
CA3046 array that is used as an external switch for the
channel hybrid.

I think this might be too tough for a digital scope to
display, and I have to say it is sounding more and more
like it is your signal generator.

Do you have any HF receivers around that you can use to
listen to the output of your signal generator at 1, 2, 3,
4... MHz, with a BFO?

I have a feeling it will sound like a aviary full of
birds.

-Chuck Harris

BUR wrote:

Hello,
<mailto:@Raymond?subject=Re:%20Beam%20modulation%20on%202465B>
Raymond Domp Frank,
<mailto:cfharris@...?subject=Re:%20Beam%20modulation%20on%202465B>
Chuck Harris,
<mailto:very_fuzzy_logic@...?subject=Re:%20Beam%20modulation%20on%2024
65B> Roger Evans,

It's awesome, I never expected such high level and precise feedback. Thanks
a lot.

Chuck

moving slightly up or down from those frequencies should
allow him to get a slow motion picture of what is really
happening.

Just 100Hz offset is enough to stop the modulation. It happens only on the
spot of 1, 2,3,4. Up to 9MHz then it goes away.


It would also be a good idea to try it with CH3/4 instead of
just CH1/2... as this would eliminate channel switching issues.

I checked on channel 3 and 4, no changes, same effect.

I would also try his signal generator with a different scope.
It wouldn't be the first time one of us was certain the problem
was the scope, when it turned out to be something else... like
ambient noise, or test equipment anomalies...

Yes, I checked with a second scope it's a RIGOL 1104Z. There is no
modulation or jitter it seems that the signal generator is clean. It's a
SIGLENT 2042X

Re: Tek 585A - Scope repair UPDATE

Chuck Harris
 

Yes, the 600W does tend to warm up a room. It used to be
a killer in the lab I worked in during graduate school. The
scopes would overwhelm the AC and it got upwards of 43C in
there.

Still, it was easy to fix, and had a pretty near flawless
display.

I still keep one on a cart, along with a 545B and 547 also
on carts. They tend to spend a lot of time parked off in
a little nook.

-Chuck Harris

Scott McGrath wrote:

Also the VAST heat output in a small shop... it alone could raise room temp by 20 deg...

As soon as i got my first 7603 it was off to a new home. The sad thing is some audiophool probably stripped it for the tubes.






Scanning software (was: Re: [TekScopes] ( the price of) printed original manuals)

Brad Thompson
 

On 11/9/2018 1:22 PM, Ted Rook wrote:
Probably the single most important thing about scanning a schematic is to NOT USE the
default document scan settings.
<snip>

Hello--

You might investigate VueScan Professional software offered by...

www.hamrick.com

The software supports 5831 scanners from 42 manufacturers (including many obsolete
models) and offers a wide range of control settings as supported by particular scanner models.

What sets the software above other packages is the level of technical support--
once you're registered, you receive notifications of free updates *without having to pester the supplier for updates*! You can download a trial version of the software.

I normally refrain from endorsing any software, but I've used VueScan with an --HP--
ScanJet 4P for several years and can highly recommend it.

73--

Brad AA1IP

scanning (was: ( the price of) printed )

John Griessen
 

On 11/9/18 10:51 AM, Brian Symons wrote:
2.  How do you get a good clean scan of paperwork that has various shades of yellowing all over it or even watermarks (from getting damp).
For photos, either documentation or selling photos, I use batch image processing with settings adjusted to the particular images. I create a folder, img-cvt-input, below where I put my camera images. Under that folder is one called output and one called crops. I use a program called cropall.py to trim the margins of photos taken to document things, then use geeqie to view them and move up if good, (overwriting the originals then). Next I run jpgs2contrast.sh from the img-cvt-input directory then view the results in output dir, and move up if good, and delete the rest to get ready for next time.

Here are those scripts if you'd like to fiddle with it.

https://www.ecosensory.com/tek/jpgs2contrast.sh
https://www.ecosensory.com/tek/cropall.py
https://www.ecosensory.com/tek/autowhite


--
John

Re: Beam modulation on 2465B

BUR
 

I just discovered that if I put back the delayed time knob for just
displaying the second trace the modulation is gone?

Re: Beam modulation on 2465B

BUR
 

Hello,
<mailto:@Raymond?subject=Re:%20Beam%20modulation%20on%202465B>
Raymond Domp Frank,
<mailto:cfharris@...?subject=Re:%20Beam%20modulation%20on%202465B>
Chuck Harris,
<mailto:very_fuzzy_logic@...?subject=Re:%20Beam%20modulation%20on%2024
65B> Roger Evans,

It's awesome, I never expected such high level and precise feedback. Thanks
a lot.

Chuck

moving slightly up or down from those frequencies should
allow him to get a slow motion picture of what is really
happening.

Just 100Hz offset is enough to stop the modulation. It happens only on the
spot of 1, 2,3,4. Up to 9MHz then it goes away.


It would also be a good idea to try it with CH3/4 instead of
just CH1/2... as this would eliminate channel switching issues.

I checked on channel 3 and 4, no changes, same effect.

I would also try his signal generator with a different scope.
It wouldn't be the first time one of us was certain the problem
was the scope, when it turned out to be something else... like
ambient noise, or test equipment anomalies...

Yes, I checked with a second scope it's a RIGOL 1104Z. There is no
modulation or jitter it seems that the signal generator is clean. It's a
SIGLENT 2042X



Roger

Rolf, do you have another scope available? If so could you look at the 'A
gate' signal from the rear of the 2465B. I believe the cpu is constantly
refreshing all the parameters that the DAC controls including the trigger
level and holdoff, so maybe if the trigger level is being refreshed just at
the time when it should trigger then the sweep will be delayed by one period
of the the input signal and the trace will appear fainter because of the
longer wait time. You might be able to see some jitter on the duration of
the 'A gate low'. If this theory is correct then going from 1MHz to 3MHz to
5MHz at the same sweep speed, the degree of flicker should decrease since
any additional delay between sweeps (the period of the input signal) should
be a smaller fraction of the period between sweeps.



Ok I checked the A-Gate on my Rigol and it seems to be distorted on the
negative side of the Square Wave. I changed the Frequency up and no change.
Eventually I could detect a small event not certain what happens exactly but
it would correspond to the fact that the modulation goes away above 9-10
Mhz.



Only Rolf can inform us whether or not the entire screen is
flickering in intensity, or if what I suspect, only a small
moving portion is flickering in intensity.

It's just the full trace of the beam like a wandering wave.

One more detail: I also activated the delayed time base and effectively the
modulation is visible on both traces.
I know the videos are not helpful perhaps some pictures at least from the
A-Gate on the second scope.

Soldering tunnel diodes

thespin@...
 

Hey all,

While I was probing the tunnel diode in my 556, one lead of the tunnel diode popped off the board. It's the kind in the gold-colored metal case, rather than the little epoxy blob. It tested spot on with a curve tracer after popping off the board, so it's still okay. I want to know the best way to resolder it to the board without damage. Any suggestions? There's not really enough room for a heat sink clamp since it uses very short leads. I suspect a little silver epoxy would be okay, but this makes it really nasty to remove if that should ever be required. My soldering iron is a metcal so it only does one temperature, so I'd prefer not to have to get an iron just for doing low melt solder. Will long needle nose pliars be okay as a heat sink along with standard solder?

Best,
Evan

Re: ( the price of) printed original manuals

Scott McGrath
 

On number 3 its called Photoshop, restoring a damaged schematic uses same steps as a damaged photo.

Content by Scott
Typos by Siri

Re: Tek 585A - Scope repair UPDATE

Scott McGrath
 

Also the VAST heat output in a small shop... it alone could raise room temp by 20 deg...

As soon as i got my first 7603 it was off to a new home. The sad thing is some audiophool probably stripped it for the tubes.

Re: ( the price of) printed original manuals

John Brown
 

I have several Artekmedia manuals and have recommended them to others. A great value of exceptional quality.

Like Dave I also though still preferred 'the real thing' when it was big, complex, and/or lots of large schematics. As to all those manuals in warehouses; perhaps if along the way some had been priced just a LITTLE more reasonably the warehouse would have been (more) empty. When Tucker emptied out (last year?) I looked at some of the stuff. Uh, if that was reduced I would have hated to see ...

Too few sellers use 'book/media' rate USPS mailing. Everyone is enamored of Priority Mail (as am I) but media is not slow domestically and it's tracked (almost everything is tracked anymore). And it can make an overall price reasonable. Have had good success just asking for media mailing.

I am a fan of the USPS. USPS is caught in an un-win-able spot. Required to provide all kinds of unprofitable services and unable to invoke cost control in any meaningful way they have never-the-less modernized and innovated so that our mail system is still among the worlds best.

So still oem (HP and Tek) manuals whenever I can; but Artek and a 27" monitor otherwise!

I love my iMac 27" Retina.

John
W0MPM

Re: ( the price of) printed original manuals

Chuck Harris
 

Yeah, that must be why I discard all of the grayscale
manuals that show up as soon as I find one done correctly.

The built in image correction features in the grayscale scanner
modes make sure that the paper looks gray, with shadows where
the paper wrinkles, or curves. And they come out to huge pdf
sizes, needing at least a byte per pixel. The large sizes
make them very slow when flipping between the pages in my pdf
reader and the grayscale makes them look sloppy done when you
print them.

The problem with what you are recommending is the documents
you are scanning are not grayscale. They are type set, and
as such are screen printed. There is no intentional shades
of gray anywhere to be found.

Grayscale is for original photographs, and original artifacts,
like a marriage license..

The only time I would use grayscale on a manual is if it was
super badly abused. Stained paper, dog eared corners, dirt
and greasy finger prints... and I couldn't get a better copy,
as it was the last one on Earth.

A further objection is if you go to grayscale, you will render
the document impossible to ocr using current ocr programs.

I stand by my suggestions. I have scanned hundreds of thousands
of pages, and tried all the different ways, and they work out
the best in my opinion.

Ask Dave Henderson how he scans. I think he qualifies as a
subject expert, even if I don't.

-Chuck Harris

Ted Rook wrote:

Probably the single most important thing about scanning a schematic is to NOT USE the
default document scan settings. These have been provided for a specific purpose and are
good at it, the purpose is the rapid scanning of medium to low resolution monochrome text
pages which is a fancy way of saying typescript and photocopies of typescript. The eye is
very good at extracting information from imperfectly scanned typescript because it is so
familiar to us from constant useage, some fine detail thrown away in scanning doesn't usually
render the text document illegible.

On the other hand your typical manual schematic is not typescript, it includes a lot of very fine
detail, and is possibly worn from handling. When scanning this kind of original instead of
using "document" scan mode the smart thing to do is to use GRAYSCALE scan mode which
when faced with less than perfect originals to scan retains a significantly greater amount of
useful tonal detail that gets thrown away in the high contrast document scan mode. The
difference can be dramatic.

Ted

Re: ( the price of) printed original manuals

Bill Riches
 

I rebuild old ham radio equipment such as R-390A receivers and collins
receivers and transmitters. I take the schematic to Staples - they enlarge
it when they scan in. I then glue it using picture spray adhesive to a
large 1/4 inch rigid foam poster board. They charge about 3 bucks to scan
it. They can do up to blue print size! The longest I have is 13" by 40 "
for a Collins R-390A receiver and a smaller 20" by 30 " for a 51J4 receiver.
Nothing lost in print quality. You need a big workbench as they can get
unwieldly due their size. But at least you can read the fine print!!

73,

Bill, WA2DVU
Cape May, NJ

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of Ted Rook
Sent: Friday, November 9, 2018 1:22 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] ( the price of) printed original manuals

Probably the single most important thing about scanning a schematic is to
NOT USE the default document scan settings. These have been provided for a
specific purpose and are good at it, the purpose is the rapid scanning of
medium to low resolution monochrome text pages which is a fancy way of
saying typescript and photocopies of typescript. The eye is very good at
extracting information from imperfectly scanned typescript because it is so
familiar to us from constant useage, some fine detail thrown away in
scanning doesn't usually render the text document illegible.

On the other hand your typical manual schematic is not typescript, it
includes a lot of very fine detail, and is possibly worn from handling. When
scanning this kind of original instead of using "document" scan mode the
smart thing to do is to use GRAYSCALE scan mode which when faced with less
than perfect originals to scan retains a significantly greater amount of
useful tonal detail that gets thrown away in the high contrast document scan
mode. The difference can be dramatic.

Ted



On 10 Nov 2018 at 2:51, Brian Symons wrote:

Since we have some knowledgeable people talking about digital paperwork
formats, perhaps we can get some hints on how to do a GOOD scan of your own
paperwork.

1.  How can you do the scanning with software & equipment that isn't
expensive.
      Do we have any users that are experts in low cost or open source
software for scanning, working with images, & pdf work.

2.  How do you get a good clean scan of paperwork that has various shades of
yellowing all over it or even watermarks (from getting damp).

3.  How do you clean up scans that are not very good quality?

4.  How do you clean up images?

Regards,
Brian.

Re: Tektronix 067-0681-01 Tunnel pulser diode Calibration tool

 

Hi Craig,

One more thing to add to Craig's extensive setup suggestions:
If I am not mistaken the 067-0681-01 also has a MAXIMUM repetition rate.
Until you figure out what that is I suggest you keep the repetition rate
under 100KHz.

Dennis Tillman W7PF

-----Original Message-----
From: Craig Sawyers
Sent: Thursday, November 08, 2018 10:37 PM
Subject: Re: [TekScopes] Tektronix 067-0681-01 Tunnel pulser diode
Calibration tool

I?m using a PG506 to generate signal. But after your comment of the
lower voltage that you got the same signal. I checked the output of
the High Amplitude and found that terminated into the 50ohm scope
setting max voltage was 33.18. Into the tunnel diode pulser and with
067-0681-01 connected at the scope bnc.
Reviewed the PG506 manual and it states

Output Load vs Voltage out
(High amplifier Output). (Pulse Amplitude Control dial)
50ohm load Min 0.3 V p-p, Max
5.2 V p-p
600ohm load. Min 1.9 V p-p, Max
32.5 V p-p
1 Mohm load. Min 3.8V p-p, Max
60.0 V p-p
The spec for the 067-0681-01 states that 60-100V is necessary, capable
of supplying at least 11mA. So about a 5.5k load at 60V and 9.1k at
100V.

The datasheet also says "The 067-0681-01 may be driven by a 60-100V
square wave such as the 1kHz square wave from Tektronix 540 series
oscilloscopes. A Tektronix 106 square wave generator, or a PG506
calibration generator may be used at repetition rates exceeding 50Hz"

There is then a footnote to say that the PG506 does not have sufficient
amplitude at frequencies lower than 125Hz.

So the PG506 should work, at least according to Tektronix.

Another Craig



--
Dennis Tillman W7PF
TekScopes Moderator

Re: ( the price of) printed original manuals

Ted Rook
 

Probably the single most important thing about scanning a schematic is to NOT USE the
default document scan settings. These have been provided for a specific purpose and are
good at it, the purpose is the rapid scanning of medium to low resolution monochrome text
pages which is a fancy way of saying typescript and photocopies of typescript. The eye is
very good at extracting information from imperfectly scanned typescript because it is so
familiar to us from constant useage, some fine detail thrown away in scanning doesn't usually
render the text document illegible.

On the other hand your typical manual schematic is not typescript, it includes a lot of very fine
detail, and is possibly worn from handling. When scanning this kind of original instead of
using "document" scan mode the smart thing to do is to use GRAYSCALE scan mode which
when faced with less than perfect originals to scan retains a significantly greater amount of
useful tonal detail that gets thrown away in the high contrast document scan mode. The
difference can be dramatic.

Ted

On 10 Nov 2018 at 2:51, Brian Symons wrote:

Since we have some knowledgeable people talking about digital paperwork
formats, perhaps we can get some hints on how to do a GOOD scan of your
own paperwork.

1.  How can you do the scanning with software & equipment that isn't
expensive.
      Do we have any users that are experts in low cost or open source
software for scanning, working with images, & pdf work.

2.  How do you get a good clean scan of paperwork that has various
shades of yellowing all over it or even watermarks (from getting damp).

3.  How do you clean up scans that are not very good quality?

4.  How do you clean up images?

Regards,
Brian.

scanning (was: ( the price of) printed )

John Griessen
 

On 11/9/18 10:51 AM, Brian Symons wrote:
2.  How do you get a good clean scan of paperwork that has various shades of yellowing all over it or even watermarks (from getting damp).
I use batch image processing with settings adjusted to the particular paper I am scanning. The scanner is run by sane on linux,
started by a script and using two other scripts that don't change much or often. My scripts are not following Dave of Artek's recommendation of thresholding as you scan, but as the image goes from step to step it does get indexed then posterized, (reduces number of greylevels), and compressed afterwards. When I have black and white pages, I call a script that does threshold all pixels into monochrome.

Here are the bash shell scripts for B&W and gray, for an Epson V300 photo model of scanner that uses the epkowa driver, and you can email me with questions:

https://www.ecosensory.com/tek/scanit

https://www.ecosensory.com/tek/bwscan_epkowa
https://www.ecosensory.com/tek/pbm2bw_png_scanadf.sh

https://www.ecosensory.com/tek/grayscan_epkowa
https://www.ecosensory.com/tek/grayorcolor2djvu-scanadf.sh

--
John

Re: ( the price of) printed original manuals

YudaMan3 <jamesvyu@...>
 

The free CAMSCANNER HD PRO app for iPhone and iPad make fantastic, READABLE, pdfs.

Re: ( the price of) printed original manuals

Chuck Harris
 

I can help with some of the questions:

1) the open source standard for scanning is XSane. It does
about everything you can do with a scanner.

2) most all of these manuals were printed using screen printing
techniques. That means that the images are made up of full
intensity pixels in varying density regions. Magnify a magazine
picture, you will see...

Since the pixels are either on, or off, it makes sense to scan
in a non gray scale mode, called line art in XSANE. That mode
sets a threshold that should catch the pixel, represents the
pixel as black or white, and should eliminate most of the
coffee stains, etc.

Always scan at the highest resolution that will give good results.
You can take away resolution, but you cannot add it back.

3) You generally can't.
4) manually if at all.

-Chuck Harris

Brian Symons wrote:

Since we have some knowledgeable people talking about digital paperwork formats,
perhaps we can get some hints on how to do a GOOD scan of your own paperwork.

1. How can you do the scanning with software & equipment that isn't expensive.
Do we have any users that are experts in low cost or open source software for
scanning, working with images, & pdf work.

2. How do you get a good clean scan of paperwork that has various shades of
yellowing all over it or even watermarks (from getting damp).

3. How do you clean up scans that are not very good quality?

4. How do you clean up images?

Regards,
Brian.





Re: Beam modulation on 2465B

Chuck Harris
 

First, I cannot reproduce this phenomenon on a 2465B, and
I used a synthesized signal source, and I also extended the
experiment by choosing other multiples of my 60 Hz line
frequency that cooresponded to his multiples of 50Hz line
frequency.


What you said doesn't contradict what I said... Or at least I
don't think so...

If the sweep repetition rate changed on a sweep by sweep basis,
you should see the entire sweep changing intensity... I cannot
be sure because computer video is a highly artifact ridden medium.

Remember what you see with a video camera when it shoots a
video of an airplane's propeller? You see a freeze frame of
the propeller that is totally warped by the CCD sensor's scan
rate.. looks more like a cartoon boom-a-rang than a propeller.

The camera used in these pictures is asynchronous to the sweep,
which is asynchronous to the phenomenon we are studying, among
other things.

Only Rolf can inform us whether or not the entire screen is
flickering in intensity, or if what I suspect, only a small
moving portion is flickering in intensity.

-Chuck Harris

Roger Evans via Groups.Io wrote:

I can't reproduce this effect on my 2465B but I have difficulty in setting my SG503 to better than 500Hz (with a frequency counter tee'd off the output). I have tried hard to find this effect so if it was there I should have seen it even if just fleetingly.

I hesitate to contradict Chuck but changes in the brightness of the trace can also be due to changes in the sweep repetition rate (not the sweep speed) and there may be a clue when Rolf finds that the effect goes away by changing the holdoff control.

Rolf, do you have another scope available? If so could you look at the 'A gate' signal from the rear of the 2465B. I believe the cpu is constantly refreshing all the parameters that the DAC controls including the trigger level and holdoff, so maybe if the trigger level is being refreshed just at the time when it should trigger then the sweep will be delayed by one period of the the input signal and the trace will appear fainter because of the longer wait time. You might be able to see some jitter on the duration of the 'A gate low'. If this theory is correct then going from 1MHz to 3MHz to 5MHz at the same sweep speed, the degree of flicker should decrease since any additional delay between sweeps (the period of the input signal) should be a smaller fraction of the period between sweeps.

This may be complete rubbish but it is fun speculating (here speaks a physicist not an engineer).

Roger