HP 198A Oscilloscope Camera: Old-School Data Collection

[@noyb7920]

Used a very similar device during my college years to provide "proof" that I'd done the experimental homework for several electrical engineering classes in the late 80s. Still have a pack of film from that time, which very likely won't work properly, but is at least still sealed in the original foil package. Yes, Gilles, I'm older than you 🤗

[@ChrissiX]

Esoteric, yes. Between your channel Technology Connections and Cathode Ray Dude I think the world is well served by such beautiful, esoteric and important information for history. Thank you. I hope you continue to produce such quality content.

[@alistentcanada]

Agreed!

[@fmphotooffice5513]

The vestigial timer is there because it's a "clockwork" Copal shutter. The last Copal shutters were made as recently as 2013. You'll find them on big 4x5 and bigger cameras where the lens is also made by another of many companies. BTW, HP is now Keysight. They still make oscilloscopes and have nothing to do with the HP brand that was sold +20 years ago. Keysight still has offices in silicon valley. Also, the last time I saw a Polaroid CRT camera, in the 1980s, if memory serves, it looked to be manufactured by Polaroid and looked like one of their cheap black plastic cameras but with a long (pre-focused?) nose.

[@steveweinberg462]

In the mid 80s, as an EE student, we used similar but simpler polaroids with the lab's oscilloscopes. Even then it struck me what a wonderfully kludgy solution that was. I recently saw on Adriene's Digital Basement that you can now get an amazingly powerful digital oscilloscope for under $100 that fits in a pocket. Wonderful time to be alive.

[@noyb7920]

lol, so it seems that "In the mid 80s, as an EE student" we both had similar experiences. (Though mine was late 80s, there were still a few profs using that instead of the o-scopes with printers attached)

[@hedgehog3180]

This is basically just the old school version of taking a picture of it with your phone, I always thought that was just a new thing with the rise of smartphones but I guess photos have always been a simple way to record data.

[@railgap]

These haven't been obsolete for TOO long; I owned a Tek scope camera in the 80s, and I still have the enormous "mainframe" o-scope (Tektronix) that it attached to. It is an analog storage scope meaning that the storage function is implemented in the CRT itself - there is no digitization or electronic memory. Interestingly, Tek made a "digitizer" (analog to digital converter) which used a storage tube as well - it was a truly exotic, one-of-a-kind "scan converter" tube designed and made by Tek and concealed inside a rackmount chassis. There was no visible display as the captured signal was exported over the then-new GPIB bus that HP originally developed. The signal from the vertical plug-in deflects a writing beam through distributed deflection plates. The electrons hit a small flat rectangular solid state target, conceptually similar to the image sensor in a digital camera. The resolution of the target is 512×512, giving 512 points in the time domain and 9-bit linear quantization of the input voltage. With a 7B92 sweeping the whole X-axis in 5 ns, and the 7912 capturing 512 samples in that sweep, the 7912 performs the function of a 100 GSample/s A/D converter. (!!) Nearly all of the units produced were purchased by the U.S. gov't. Digitizing scopes existed at the time, but their sample speed was slow, meaning they were fine for repeating signals, but if you wanted to capture a single transient event, one couldn't have a good waveform; there weren't enough samples before the event was over. In fact, the official name of the original R7912 was "Transient Waveform Digitizer". Analog storage tubes and the 7912 could capture one-shot waveforms with excellent resolution. They were breathtakingly expensive even before the plugins were purchased, although it used 7000 series scope plugins so if you had a fast vertical amp already for a scope, you could use it in the 7912. Astonishingly, my old 7904 storage scope, built in the 1980s, still works fine. Tek really built good stuff. When it was new, it was $17K with no options and no plugins. I bought mine in the 90s, stuffed with thousands of dollars worth of great plugins, and including four nice Tek probes, for $200, thankfully the ebay seller was near my town so I didn't have to ship the beast. The dedicated Tek scope cart (you don't want to try carrying the thing, handle or no handle) I picked up at a local surplus store for $10. I also have a logic analyzer plugin which turns the scope into a 16-bit logic analyzer.

[@unixux]

Did you say 100 GS/s

[@brunonikodemski2420]

We used variants of these for very high speed work, mostly for ESD, weapons, or nuclear work. Later they were replaced by electronic versions, where the CRT had an electronic snapshot taken, as fast as possible. These were used as a standard "save the data on the screen" for decades, in all high speed situations. Triggering was a problem, since it was not capable to go anywhere near the 1-microsecond required zone, until later models. Eventually HP designed 1-nanosecond triggering, which worked well, and was capable of capturing slapper explosives as they developed along the plates, and similar 30,000-foot-per-second events. They actually worked very well, for that time, and were state-of-art.

[@cocotoni1977]

I remember polaroids with oscilloscope traces stuck in my dad's graduate thesis. Always wondered how they were made. Thanks for jogging that memory.

[@billharris6886]

I used a variation of the 197A camera to document oscilloscope and spectrum analyzer traces for reports. This camera used the Polaroid film cartridge that came out in the early 1960's. If I remember right, the film was 1100 ASA B&W. To focus the camera we would pull out the film pack and use a focusing plate in place of the film pack. The camera took relatively good photos, assuming the trace intensity was uniform across the CRT face. Given the fast film, the exposure latitude was quite narrow so, the trace intensity across the CRT face had to be constant. As a bonus feature, the camera could also be used to take passport or driver's license grade photos of your lab mates as a joke. The image barrel distortion made such photos a bit creepy looking.

[@SeanBZA]

Sync input normally is connected to the oscilloscope, set for manual triggering, so that the trace only comes across the screen once the trigger condition is met. Otherwise the screen is blanked. Auto trigger, or on the old oscilloscopes the free run position, always will display a trace in X axis, while the manual trigger mode only will show a trace when either the input passes a threshold, or is above it and above a frequency, or above it and the high frequency noise is filtered out, or uses the incoming AC mains peak as a trigger source, or an external voltage level to trigger. That way your film does not get a big band of bleed light from the base level put on it, which means you can run the screen at a very high brightness, to capture fast events, as they are still able to provide enough light to excite the film. An aside is that later scopes with memory had a multichannel plate in the front of the CRT, and would hold an image for a few minutes after it was written, making it easier to photograph as you simply left the film exposing for a minute or two, so the faint image would be recorded. I had a very similar device, except it used a non developing film, very heat sensitive thermal paper, and ran the CRT very bright, with the film pressed against the glass, so the bright spot would put enough energy into the paper to expose it. Worked well enough, but very slow, used originally as a recorder for ECG or other signals, and if you wanted a long term record you would have to use a photocopier to immediately make a copy, or use a polaroid camera to take a photograph of the paper strip, as it would fade with time.

[@charleslaing3426]

I used the simpler Tektronix camera in EE Lab in 1969. I also used a Visicorder oscillograph that had miniature galvanometers and wrote with UV light on sensitized paper rolls.

[@Dennis-uc2gm]

I never really ran across any of the HP scope cameras, but was very familiar with the Tektronix C50 series in the mid 70's. I use to work in a calibration Lab and we had to issue them out to Lab tech's , keep them clean and loaded with fresh Polaroid film. Thanks for being able to see another side to capturing O scope screen data. 👍

[@SkyhawkSteve]

There were a few years at work where we needed to document waveforms, and the Polaroid scope camera was the tool that we used. Polaroids do generate a lot of trash with each photo, but this was the only way to record waveforms at the time. Modern digital scopes that can just save the image to a thumb drive are an incredible convenience by comparison!

[@rrhine]

I remember a similar thing being used for electronic warfare, where the operators would take photos of the spectrum being monitored. Specific frequencies would come up and be tracked for analysis.

[@nasabear]

When I worked at the Naval Research Laboratory in the late 70s, they used a camera setup like this to take data from their optical experiments. I would then take the photos and digitize them on a very early manual digitizer, pressing the pen onto successive points along the trace in the photo. The digitizer would output the coordinates directly onto punch cards! How times have changed...

[@DerrangedGadgeteer]

At the Atomic Museum in Las Vegas, they have several racks of oscilloscopes from early nuclear weapons testing. They're daisy-chained together, triggering in a cascade one after the other, and they have Polaroid branded film holders over all the screens. It's fascinating!

[@noelandrew3600]

Very interesting, i have a load of Oscilloscopes in my collection including a couple designed to go with this camera and some of the HP scopes that came out after with early Flash type memory and at least one that takes a 3.5inc floppy disk. I collect old test gear so have about 30 scopes in total and plenty of other test gear like VTVM and sig gens and counters. so really enjoy seeing things like this that i will need to add to the collection at some point if i can.

[@ChrisAthanas]

Super cool

[@bluesatin]

I like your addendum at around 14:55, about examining problems that people have run into the past, and how they found solutions to them. Learning how people approached problems and how they came up with innovative solutions is a great way of giving you ideas and frameworks to approaching problems when you run into similar situations yourself, even if they're not directly comparable. One thing I really appreciate about your videos is that you make sure to clearly communicate what was the actual problem that people had, and then you introduce the device that was used to solve that problem and how it achieved that. I notice quite frequently that people just end up explaining what something is doing, rather than *why* it's doing that thing; and without understanding why things are done in a certain way, it's incredibly hard to actually apply that knowledge to other situations.

[@PBGetson]

05:25 The flood pulse gun would probably only have to fire once, and the film would then be able to register many faint traces using the eleven body detente positions.

[@ibrahimkocaalioglu]

Very close to 100k subscribers. Good luck. I thought you would talk about the osciloscope next to as well. You had a large baggage allowance while these things take a lot of space.

[@MM.]

A logical continuation of this approach was to draw and photograph animation frames on the kind of high resolution storage tube CRTs (basically CRT-based etch-a-sketches operating at well below 1fps) that were available on terminals like the Tektronix 4010 series in the second half of the 1970s. Various early CGI was created in this manner.

[@pederschultz3283]

Very fascinating to see, how one took screenshots in the analog age.

[@the_bw_trekkie]

ngl for a second there I thought this was a curiousmarc video just from the title alone

[@maltoNitho]

Same. But I’m not mad

[@tmanF4]

The overlap is insane, loving both their channels

[@Alchemetica]

Now I understand the reason for the look and how they were made of the black and white trace oscilloscope images in books of the day.

[@bshoke]

I knew that was a land camera as soon as I saw it. My first vintage camera was a land camera even though I never had access to that roll film.

[@fakejones6858]

Not to be pedantic, but the shutter speed dial on the 197A actually appears to go from 8 seconds to 1/30th of a second. Either that, or what appears to be an "8" is actually a bulb function, which would keep the shutter open as long as the shutter release is held down. It also has a "T" setting which would likely be for an external timer or could be the bulb function if there actually is an 8 second setting. (That probably makes no sense and really demonstrates how clearly you present obscure subjects.) But as an indicator of how thorough and detailed your videos are, I had been in the professional photo lab industry for 40 years and while I had heard of it, I never understood how pre-fogging film increased it's sensitivity. There's always something new to learn., and you do a great job of passing along information.

[@aritakalo8011]

I think it's actually B, not an 8. As he mentioned later with 198A, this is B for bulb mode for long exposure. In practice meaning, shutter is directly tied to the trigger actuation. As long as trigger button is pressed, shutter stays open. Instead of trigger button triggering the timed shutter sweep. 197A also seems to have T, which would be for (externally) timed exposure. Meaning first trigger triggers the shutter open, but it latches that way. Only closing on trigger being triggered again. Both probably usefull for certain experiments with the external electric trigger connections. One could wire up ones long experiment with external timing module with adherence to the bulb or timed mode. With external rig there would be no problem turning bulb mode to externally timed. Just have electronic timing setup latch down on the trigger for as long as you needed.

[@TomFarrell-p9z]

Is pre-fogging similar to "hypering" the film, that astronomers used to do sometimes? Edit--just looked it up on Wikipedia, and it sounds almost like they are opposite processes, with re-fogging making the film more sensitive for short exposures, while hypersensitizing makes the film work better for long exposures.

[@fakejones6858]

@@aritakalo8011 That's what I get for shooting off my mouth before I finish watching the whole video... And in case anybody is wondering, the term "Bulb" is used because early shutter release systems in photography were pneumatic, so the photographer would trip the shutter by squeezing a rubber bulb like the ball on the end of a turkey baster.

[@cmacvane]

Pedantic, regardless.

[@StubbyPhillips]

Sad how HP went from respectable technology leader to making crappy plastic printers with ink refill scams.

[@noyb7920]

HPE's possibly still not too bad, but I definitely stay away from their consumer products these days.

[@laptop006]

The non-computer/printer bit of HP was spun off as Agilent in the late 90s, then much later the test equipment division got spun off again as Keysight.

[@eyerollthereforeiam1709]

Sigh.. Remember the good old days when a corporation name actually meant something?

[@KeithZim]

Na what is sad is that people still think printing should be cheap. Laser or stay home..... Powdered toner does not dry out. They can sit for months or years between print's without fail...

[@JCWren]

@@KeithZim So... printing should not be cheap? Also, a good color ink jet or wax printer prints a far better color image than a CMYK laser. The real problem is that companies are use the Gillette model for printers and screwing customers to the wall with refills. It's said that the cost per gallon of ink based on the amount in a cartridge is between $5K and $10K per gallon. And then these companies want to put cartridge protection to prevent consumers refilling them. Slightly understandable because the printers are designed for ink meeting certain specifications, but you use some garbage Chinese refill ink and then try to warranty the printer when it prints poorly or not at all. Manufacturers need to stop using consumers as cash cows and provide reasonable ink cartridge prices.

[@marjon1703]

I Still have polariods of traces from back in the day making uM detectors.

[@patrickshannon4854]

Recalling many oscilloscope images in instruction texts or hobby magazine articles, it never occurred to me how they captured the images. As a nav equipment tech in the USAF, I used a variety of hp test equipment. I admired & frankly lusted after such finely & cleverly manufactured equipment. Quote from blood sucking Jarrasic Park lawyer, "Is it heavy? Then it's expensive."

[@michaelparker1813]

Welcome back. I hope you had a great vacation.

[@atkelar]

I have recently restored a Tektronix curve tracer and wanted to get a matching camera for it; sadly, the one I found doesn't quite fit. I'm now planning to make my own adapter for a regular tripod mount so I can snap a clean picture with a compact camera.

[@JCWren]

I see you've rearranged the shelves. I'm really hoping you do a video on blowtorches, like the one you had roughly where the E6B Flight Computer is setting.

[@hedgehog3180]

It's weird how smartphones these days are so useful for physics experiments that physics exams are like the only exams where you're allowed to use them. A lot of their features might seem kinda pointless but they're genuinely useful in a lot of physics experiments.

[@DanielLopez-up6os]

For Graflex Backs Fuji still sells film for Oscilloscopes or X ray equipment etc. Standard 4x5 or 8x10 film or any size etc. Fuji Super Hr-U, you can get it either especially sensitive to green, or sensitive to all.

[@theafro]

My own workshop still hasn't progressed past the "squint and try to remember what it looked like" method of oscilloscope capture. an oscilloscope camera is high-tech as far as I'm concerned!

[@RCAvhstape]

You can probably just use your phone camera for many of these applications now.

[@theafro]

@@RCAvhstape wait, your camera has a telephone in it, whatever next!?

[@RCAvhstape]

@@theafro Nope, my camera has a phone in it.

[@theafro]

@@RCAvhstapeit has a phone in it that isn't a telephone? what kind is it? hydrophone? gramophone? xylophone? you have confused me terribly?

[@woodwaker1]

I never used a camera on an O scope, but remember some old ones, I think they were tube based from when I was in the USAF 1969-1973. When I got into repairing early computers we had solid state Tektronic scopes.

[@MrXenon1977]

As always: Fantastic neeche and nerdy content - this is the good stuff in YT! Do you intend to make a video about the phase angle meter of the intro? It looks like a small device that could be quite mighty in the right hands. It´d be fantastic to get an overview about its use cases.

[@Allan_aka_RocKITEman]

Great video, Gilles...👍

[@alasseon99]

Could this type of camera be used with HP curve tracers? Curve tracers used "memory" display with slow phosphorus to allow time for penciling data to paper. As usual, excellent work!

[@MichaelEdelman1954]

We had a simpler HP Polaroid camera in a lab I worked in during my grad school days in the late 1970s. I suspect it dated from much earlier. That one had a pistol grip and was simply held against the scope face.

[@nobilismaximus]

Do an episode on the printrex wireline and LWD printer for oil wells,

[@shmehfleh3115]

I found an early 80s DSO at a thrift store a little while ago, complete with an onboard 5 1/4" full-height Shugart floppy drive. The thing is huge, and must've cost a fortune when it was new; that floppy drive alone probably cost around $500. Still, I'll bet it was a godsend just pushing a button on the scope and saving the trace data to a disk.

[@Grey_Duck]

Was anyone else expecting the oscilloscope in the intro to turn red and say “I’m sorry, Dave. I’m afraid I can’t do that.”

[@ronchappel4812]

Given the green ring i was thinking it was a comedy cartoon version of HAL.Yes,my mind does wander in strange directions😆

[@browntown52]

Great as usual, just wondering if this is a Canadian thing? I hear you say oh-sill-a-scope. Always understood it to be ahh-sill-a-scope just like ahh-sill-late. Scopes will start following you home. Their like chips, can't have just one. Tektronix 400 and 500 series are my faves, but Apollo era HP gear is always the best. Open them up and sit in awe of the engineering and workmanship. Something as simple as a 3310a function generator has 4 boards with gold traces in a box smaller than a toaster.

[@bborkzilla]

I used to have one of those scopes - I always wondered what that function was for.

[@dell177]

We used the Tektronix equivlent with a pack fil;m back. Later on we had a small epson plotter that ran over GPIB and had 4 pens so you could plot in color.

[@davidbono9359]

I have a Tektronix 2252 oscilloscope that produces screen copies on an Centronics-compatible PC printer attached to a parallel port on the scope. Unfortunately, I don't (currently) have a printer to try it out. These are kind of a transitional solution between the earlier scope cameras, and the digital storage scopes that came later.

[@SeniorChief604]

Back in the 1970's we used a similar Polaroid camera system to record CT scans.

[@jamesrivettcarnac]

That is a great meterology tie

[@jimsvideos7201]

Aw dang Gilles, you have the best toys.

[@michaelogden5958]

I used a lot of HP measurement and recording (not sound recording) equipment in labs in the early 80s. The thing I think about when early-ish HP products come to mind is so-called Reverse Polish Notation - a programming language (?) they used. It worked just fine, but you kinda had to put your brain on backwards when programming.

[@robertschnobert9090]

Awesome video 🌈

[@MrSearay1962]

Great video!

[@nobilismaximus]

Your suits are getting better. Still too heavy on the shoulder pads. Really enjoy the content. 10/10

[@charlesurrea1451]

Sorry to hear about the Tin Cup. You do have a real job though right? Do you sell digital copies of the old manuals and such? It seems that information is highly valued. I had seen two fellows nearly come to blows at an auction over a water purifying machine manual .

[@jeffclark2725]

Thumbs up,great camera video

[@Rutherfordium2023]

polaroid pack film was used so extensively it really is a tragedy that it went out

[@bobcfi1306]

Well done

[@campbellmorrison8540]

Funny you should talk about oscilloscope cameras, I was clearing my shed ( or trying to ) and came across a Tektronix one, now I'm feeling bad for having dumped it

[@olafzijnbuis]

At 11:16 It's so stupid that you can not lock the focus setting. (as far as I can see that is).

[@kidmohair8151]

yaknow. I thought your channel's mission was to present us with inventions and devices that the majority of the population would have never dreamed were necessary or even wanted, but were made anyways...

[@Laundry_Hamper]

Ever see an analogue fundus camera? Nikon made one using an F body, I'm sure there are others but theirs is fairly easy to find. A Bond-style barrel-vision intro wearing a doctor's head mirror would be fitting :P

[@huddunlap3999]

I remember a photography trying out a 30,000 ASA film from this era.

[@RCAvhstape]

Ah yes, the days when HP was known not for consumer laptops but for high quality test equipment, which weighed a ton and cost a lot, and was worth every penny. The general rule for electronics labs back then was "Tektronix for oscilloscopes, HP for everything else. And don't forget your Simson 260 multimeter."

[@RickO.-vq8oh]

HAL's Cousin in the Intro ??

[@megazoid]

I'm sorry Dave, I'm afraid i didn't get that... reference.

[@311stylin]

Wait.... was that intro swell from the movie Heavy Metal?

[@WOFFY-qc9te]

Phasenwinkel-Messgerät Now thats interesting, with a name like that a must have for any chaps cave.

[@philgiglio7922]

9:32 sorry Giles, but those appear to be 'D' cells NOT 'C'

[@petersage5157]

8:55 Nice.

[@User_Un_Friendly]

I thought it was a toaster...designed by you, Giles. 😂🤣 Having owned an HP RPN (Reverse Polish Notation) calculator in high school, I can verify if there was a complicated way to do ANYTHING, HP will inevitably choose that paradigm. Every calculator I was looking at, had ways to reinsert the modulus back into the current calculation on the Stack. WHO DOES THAT?! 😂🤪😵‍💫

[@Themanwithnoscreenname]

[another camera video] Where does Gilles get all these picture perfect devices?

[@dziban303]

What kind of UV bulb was used?

[@zinckensteel]

4 cm/ns? Holy crap, that's like 10% the speed of light!

[@hypercomms2001]

A time when Hewlett Packard was not "In Search of Excellence", as it was an excellent company that engineers like myself scrambled to have.. Now it is a company that screws it customers with its printers and ink print cartridges.... I threw out my HP printer because of it...

[@alansmith8837]

Sorry cheap shot but wouldnt it have been easier to take a screen shot

[@conradharcourt8263]

To be honest the unfunny short opening sequences are getting a little tiresome.