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Amazing video from ATT archives freely available on youtube

Laurence Oberman
 

https://m.youtube.com/watch?v=DovunOxlY1k&t=1054s

This is amazing. No computer graphics no simulation. Pure mechanical depiction of SWR and wave behavior using a device invented by the folks at ATT.
This is one of the most ingenious videos I have seen in a long time.

Enjoy

73
KB1HKO

Laurence

Kelly Mabry
 

I watched it also... awesome

73,
Kelly K5AID 



Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------
From: Laurence Oberman <oberman.l@...>
Date: 4/25/19 3:30 AM (GMT-06:00)
To: BITX20@groups.io
Subject: [BITX20] Amazing video from ATT archives freely available on youtube

https://m.youtube.com/watch?v=DovunOxlY1k&t=1054s

This is amazing. No computer graphics no simulation. Pure mechanical depiction of SWR and wave behavior using a device invented by the folks at ATT.
This is one of the most ingenious videos I have seen in a long time.

Enjoy

73
KB1HKO

Laurence

馬玉麟 <patrickylma@...>
 

Thanks for your sharing and the links


Laurence Oberman <oberman.l@...> 於 2019年4月25日 週四 下午4:31寫道:

https://m.youtube.com/watch?v=DovunOxlY1k&t=1054s

This is amazing. No computer graphics no simulation. Pure mechanical depiction of SWR and wave behavior using a device invented by the folks at ATT.
This is one of the most ingenious videos I have seen in a long time.

Enjoy

73
KB1HKO

Laurence

Dan Schaefer
 

 Really neat demonstration.   Thanks for sharing. 
Dan. W3BU 



On Apr 25, 2019, at 4:30 AM, Laurence Oberman <oberman.l@...> wrote:

https://m.youtube.com/watch?v=DovunOxlY1k&t=1054s

This is amazing. No computer graphics no simulation. Pure mechanical depiction of SWR and wave behavior using a device invented by the folks at ATT.
This is one of the most ingenious videos I have seen in a long time.

Enjoy

73
KB1HKO

Laurence

Tom, wb6b
 

On Thu, Apr 25, 2019 at 01:31 AM, Laurence Oberman wrote:
This is amazing. No computer graphics no simulation
Hi,

Here is a video (film), in 1959, counting individual photons with nothing but old oscilloscopes, incandescent lamps and a motorized spinning pinhole. Also amazing.

https://youtu.be/HUsNFLpDsTw

I love these old videos.

Better yet, no handwaving, screaming and mugging for the camera, in artificially created excitement about the amazement of quantum physics and light.

Tom, wb6b


Additional comment: The mechanical depiction of SWR video was really interesting, too. Just one point. If you don't have a significant part of a wavelength in a cable or other connection, SWR really is not a factor. Unless you are dealing with microwaves, if you are talking about the impedance match between stages in a transmitter, most likely a "mismatch" in driving the finals (for example, as I often hear described) is not reflecting anything nor has an SWR. But it is still a convenient way to describe impedance matching as so many tools, like smith charts, are built around the concept. 

Nigel
 

Thank you for sharing, absolutely fascinating for sure!  

Wonder how (if?) high schools teach same subject / topic  nowadays?

Guess its the 'old school' I belong to that make watching enjoyable, perhaps not enough 'showbiz' or 'drama' for today's young students.... (as also noted in another comment).

73

Nigel ZS6RN ex G8DEV

Jerry Gaffke
 

SWR was about the only thing they could measure 100 years ago, 
just run some sort of RF voltmeter along the open wire transmission line to the antenna
and measure the peaks and troughs.

Would be more informative to know the complex impedance of the load,
but SWR is still easier to measure and it's what hams are most familiar with.

Jerry, KE7ER


On Thu, Apr 25, 2019 at 08:01 AM, Tom, wb6b wrote:
Additional comment: The mechanical depiction of SWR video was really interesting, too. Just one point. If you don't have a significant part of a wavelength in a cable or other connection, SWR really is not a factor. Unless you are dealing with microwaves, if you are talking about the impedance match between stages in a transmitter, most likely a "mismatch" in driving the finals (for example, as I often hear described) is not reflecting anything nor has an SWR. But it is still a convenient way to describe impedance matching as so many tools, like smith charts, are built around the concept. 

Laurence Oberman
 

Yep, For me the thing about this video was the ingenuity to use the
pivoting metal rods like that to show the wave motion.
Amazing, still cant get over how he came to that idea.

On Thu, Apr 25, 2019 at 4:45 PM Jerry Gaffke via Groups.Io
<jgaffke=yahoo.com@groups.io> wrote:

SWR was about the only thing they could measure 100 years ago,
just run some sort of RF voltmeter along the open wire transmission line to the antenna
and measure the peaks and troughs.

Would be more informative to know the complex impedance of the load,
but SWR is still easier to measure and it's what hams are most familiar with.

Jerry, KE7ER

On Thu, Apr 25, 2019 at 08:01 AM, Tom, wb6b wrote:

Additional comment: The mechanical depiction of SWR video was really interesting, too. Just one point. If you don't have a significant part of a wavelength in a cable or other connection, SWR really is not a factor. Unless you are dealing with microwaves, if you are talking about the impedance match between stages in a transmitter, most likely a "mismatch" in driving the finals (for example, as I often hear described) is not reflecting anything nor has an SWR. But it is still a convenient way to describe impedance matching as so many tools, like smith charts, are built around the concept.

Tom, wb6b
 

Hi,

It is interesting that the Bell Labs film and the MIT film both came out in 1959. In reading a little about the presenters in the films it looks like this was no accident. The Sputnik satellite launch sent shockwaves through the US and there was a big push for more and better science education. 

Both of these people (and certainly many more) obviously were very smart and interested in improving the physics education of the time. It is a good thing they were there to invent the teaching tools they did. Without the big science push of the day, maybe only the few that attended their lectures personally would have been lucky enough to see these demonstrations. It is fun (and educational) to see these time capsules from the beginnings of the space age.

https://en.wikipedia.org/wiki/John_N._Shive
https://en.wikipedia.org/wiki/John_G._King_(physicist)
https://en.wikipedia.org/wiki/Physical_Science_Study_Committee

A side note. Right after the Bell Labs wave video was another old video by Tektronix on transmission lines. The interesting thing they did was send narrow pulses down a long coax cable and look at the pulses into the cable with open, short and proper termination. Had fun doing the same experiments this evening with a signal generator, scope and a long piece of cable TV coax. Also tried source termination, where the output of the coax is unterminated, but you terminate the input of the coax with a series resistor to the center conductor. I'd used the source termination method for sending digital data down ribbon cables in the past. Was fun to do this again just for play and remind myself it actually works. 

Thanks Laurence for linking the original video, it lead to a bit of fun and learning.

Tom, wb6b

Robert D. Bowers
 

I enjoyed the video... it was a good example of how physics COULD be taught... very instructive and helpful in showing how they came up with ways to test various hypotheses with relatively simple equipment.  (The video helped me to understand how they tested the idea of photons and their reasoning behind the test, something I'd wondered about in the past - and I'd had a year of physics.  I know how they showed the wave aspects of photons... learned that in high school.)

I would add that I've seen (and even owned, until someone torched my shop/lab) some really old test equipment, dating back into the 20s and 30s (plus a few electronics books and manuals from the same period and earlier - all ashes).  I know that the impedance bridge was old... dating to the mid 20s if not a bit earlier, and hams would 'roll their own' test equipment a lot back then.  They had some interesting ideas and equipment, back to the earliest days of radio.  Some of it would be a big problem today (rotary gap transmitter for instance), but it worked for them, and from what I remember reading back when I was a kid, they were well aware then of many of the problems inherent in the equipment being used and had novel ways of testing different aspects of radio.

My favorite piece that I lost in the fire (besides my books, radios, and modern equipment) was an optically amplified meter - that would measure a tiny fraction of a microamp.  They used a very sensitive meter movement, and used a light source to project it onto a wide screen.  It really worked well, and as I remember (the shop was torched in 2010), it dated well before 1920.  Beautiful finished wood cabinet, brass trim, and very well made (rather typical of the period).  (I also used to have a scope very much like the one in the video, but never really used it much - let it go years before.)

My in-laws, before they passed, had a big receiver that would receive from longwave clear up through shortwave - it dated (again, as I remember) to the 20s or 30s, well before WWII.  Again, gorgeous fancy wood cabinet (I think solid oak), brass and either nickle or silver trim, you name it.  Radios and test equipment were BUILT back then...

Bob

N4FBZ

On 4/26/19 7:31 AM, Tom, wb6b wrote:
Hi,

It is interesting that the Bell Labs film and the MIT film both came out in 1959. In reading a little about the presenters in the films it looks like this was no accident. The Sputnik satellite launch sent shockwaves through the US and there was a big push for more and better science education. 

Both of these people (and certainly many more) obviously were very smart and interested in improving the physics education of the time. It is a good thing they were there to invent the teaching tools they did. Without the big science push of the day, maybe only the few that attended their lectures personally would have been lucky enough to see these demonstrations. It is fun (and educational) to see these time capsules from the beginnings of the space age.

https://en.wikipedia.org/wiki/John_N._Shive
https://en.wikipedia.org/wiki/John_G._King_(physicist)
https://en.wikipedia.org/wiki/Physical_Science_Study_Committee

A side note. Right after the Bell Labs wave video was another old video by Tektronix on transmission lines. The interesting thing they did was send narrow pulses down a long coax cable and look at the pulses into the cable with open, short and proper termination. Had fun doing the same experiments this evening with a signal generator, scope and a long piece of cable TV coax. Also tried source termination, where the output of the coax is unterminated, but you terminate the input of the coax with a series resistor to the center conductor. I'd used the source termination method for sending digital data down ribbon cables in the past. Was fun to do this again just for play and remind myself it actually works. 

Thanks Laurence for linking the original video, it lead to a bit of fun and learning.

Tom, wb6b
_._,_._,_


David Wilcox
 

If you watch the YouTube videos of how Japan became an electronics center after WWII they also couldn’t measure current small enough with their available meters so they put a mirror on the needle of the large meter they had, shined a light on the mirror, and measured the changes on a spot on the wall many feet away.  They did that with many of their manufacturing ideas when the US would give them the specs on a chip or other part but didn’t give them the “how to” for the project.  Used a lot of brain power of a few young minds when the US used massive research facilities and high end equipment developed during the war.  Neat four part series “A video history of Japans electronics industry”.... well worth watching. Explains a lot of things I never knew since I was born after the war. 

David J. Wilcox K8WPE’s iPad

On Apr 26, 2019, at 11:44 AM, Robert D. Bowers <n4fbz@...> wrote:

I enjoyed the video... it was a good example of how physics COULD be taught... very instructive and helpful in showing how they came up with ways to test various hypotheses with relatively simple equipment.  (The video helped me to understand how they tested the idea of photons and their reasoning behind the test, something I'd wondered about in the past - and I'd had a year of physics.  I know how they showed the wave aspects of photons... learned that in high school.)

I would add that I've seen (and even owned, until someone torched my shop/lab) some really old test equipment, dating back into the 20s and 30s (plus a few electronics books and manuals from the same period and earlier - all ashes).  I know that the impedance bridge was old... dating to the mid 20s if not a bit earlier, and hams would 'roll their own' test equipment a lot back then.  They had some interesting ideas and equipment, back to the earliest days of radio.  Some of it would be a big problem today (rotary gap transmitter for instance), but it worked for them, and from what I remember reading back when I was a kid, they were well aware then of many of the problems inherent in the equipment being used and had novel ways of testing different aspects of radio.

My favorite piece that I lost in the fire (besides my books, radios, and modern equipment) was an optically amplified meter - that would measure a tiny fraction of a microamp.  They used a very sensitive meter movement, and used a light source to project it onto a wide screen.  It really worked well, and as I remember (the shop was torched in 2010), it dated well before 1920.  Beautiful finished wood cabinet, brass trim, and very well made (rather typical of the period).  (I also used to have a scope very much like the one in the video, but never really used it much - let it go years before.)

My in-laws, before they passed, had a big receiver that would receive from longwave clear up through shortwave - it dated (again, as I remember) to the 20s or 30s, well before WWII.  Again, gorgeous fancy wood cabinet (I think solid oak), brass and either nickle or silver trim, you name it.  Radios and test equipment were BUILT back then...

Bob

N4FBZ

On 4/26/19 7:31 AM, Tom, wb6b wrote:
Hi,

It is interesting that the Bell Labs film and the MIT film both came out in 1959. In reading a little about the presenters in the films it looks like this was no accident. The Sputnik satellite launch sent shockwaves through the US and there was a big push for more and better science education. 

Both of these people (and certainly many more) obviously were very smart and interested in improving the physics education of the time. It is a good thing they were there to invent the teaching tools they did. Without the big science push of the day, maybe only the few that attended their lectures personally would have been lucky enough to see these demonstrations. It is fun (and educational) to see these time capsules from the beginnings of the space age.

https://en.wikipedia.org/wiki/John_N._Shive
https://en.wikipedia.org/wiki/John_G._King_(physicist)
https://en.wikipedia.org/wiki/Physical_Science_Study_Committee

A side note. Right after the Bell Labs wave video was another old video by Tektronix on transmission lines. The interesting thing they did was send narrow pulses down a long coax cable and look at the pulses into the cable with open, short and proper termination. Had fun doing the same experiments this evening with a signal generator, scope and a long piece of cable TV coax. Also tried source termination, where the output of the coax is unterminated, but you terminate the input of the coax with a series resistor to the center conductor. I'd used the source termination method for sending digital data down ribbon cables in the past. Was fun to do this again just for play and remind myself it actually works. 

Thanks Laurence for linking the original video, it lead to a bit of fun and learning.

Tom, wb6b

Jerry Gaffke
 

Japanese electronics were about on par with the US during the war, 
but by the end of the war all their facilities were piles of rubble.
They still knew how.

The first translantic telegraph cables of 160 years ago were fighting a huge capacitive load.
Search for "329" in this text     http://atlantic-cable.com/CablePioneers/Kelvin/
to see a description of the mirror galvanometer developed by Lord Kelvin for the project.

Jerry, KE7ER


On Sat, Apr 27, 2019 at 02:56 AM, David Wilcox wrote:
If you watch the YouTube videos of how Japan became an electronics center after WWII they also couldn’t measure current small enough with their available meters so they put a mirror on the needle of the large meter they had, shined a light on the mirror, and measured the changes on a spot on the wall many feet away.  They did that with many of their manufacturing ideas when the US would give them the specs on a chip or other part but didn’t give them the “how to” for the project.  Used a lot of brain power of a few young minds when the US used massive research facilities and high end equipment developed during the war.  Neat four part series “A video history of Japans electronics industry”.... well worth watching. Explains a lot of things I never knew since I was born after the war. 

David J. Wilcox K8WPE’s iPad