This film is a real gem. I'm an engineer (and used to be a professor) and the clarity of explanation in this film is exceptional. It is the best explanation of SWR that I've come across to date. This man would have been a favorite teacher had I had the opportunity to sit under him.

@emylrmm

4 жыл бұрын

indeed, this was very well done

This video acts as an impedance matching network between this topic and my brain. Perfect!

@aaronfrank9649

3 жыл бұрын

Good one!!!!!

@003abhijith

2 жыл бұрын

well said... same for mee too☺️

@donsudduth

Жыл бұрын

Works better with tapered glasses

@Inception1338

11 ай бұрын

I have no clue what you just said.

@Gukworks

11 ай бұрын

Gold

This dude has a very slightly evident grin that appears when he knows he's explaining something enlightening. You can tell he loves what he's teaching.

@projectartichoke

Жыл бұрын

Yes! his love of the material is extremely engaging, at least I found it so.

@faneuil1

11 ай бұрын

agree- probably was a very nice guy -- it is obvious he loved to teach. made me smile

You can tell from his expressions that this guy is having a blast talking about this.

@nukiduki2

3 жыл бұрын

Right? Like he knew we'd get it!

@SplendidKunoichi

Жыл бұрын

I couldnt help but think this the entire video. such a great thing he knows he's been able to do here

I have learned more about waveform in this 30 minute video than 7 years of being an amateur radio operator. Great explanation and video.

What an utterly gifted teacher Dr. Shive was, and what a gift Bell Labs gave us by preserving his work on film.

My dad worked at Bell Lsbs and I had a basement full of test gear and jars of vintage transistors to toy with as a kid, and consequently have always had electronics and radio close to my heart and am still learning the deeper aspects of those subjects. Bell Labs was an amazing place, there were actually two, one in Murry Hill, NJ, where the transistor was invented, and one in Holmdel, NJ, where my father had worked and did quite a bit of transmission cable work and later fiber work. There was a white water tower there at the campus in Holmdel with 3 support columns, which oooked suspiciously like an oversized transistor; the joke was someday someone would paint E, B, and C for emitter, base, and collector on the bottom of the tower to properly label the “leads” of the water tower. That kind of research is where it’s at, we need to get back to that collaborative multidisciplinary approach with a big center and a big budget to push the technology frontiers hard again. For example, the west needs workable fusion power, and the fragmented approach is perhaps costing more in lost time, than it is saving in dollars.

Maybe this has been commented earlier in this thread… About 5:30 into the film, John Shive talks about the termination of an electrical transmission line. At first, I thought John Shive was wrong, since I have truly seen the opposite in our lab. What I have seen on an oscilloscope is a wave that returns “upside down” from a short circuit termination, while an open circuit termination gives a reflected wave with the same phase as the incoming wave. But John Shive talks about a current while an oscilloscope measures voltage. At an open end, the law of conservation of energy results in the pulse having to return to where it came from (since it has nowhere else to go). Going back, a current would have to pass through an imaginary amperemeter in the opposite direction compared to its original direction, thus giving a current with the opposite sign. So, John Shive was right about the current. Why doesn’t the voltage change polarity as well? This also has to do with energy. The termination and the ideal wires do not “steal” (convert) or store any energy. Therefore, the sum of energy from the forward and the return wave must be zero, E(forward) + E(return) = 0 and E(forward) = -E(return). The minus-sign comes from the inverted current, therefor the voltage can’t be inverted. Anyone who agree with me?

@D0nK3yDon

2 жыл бұрын

I had the same initial thought, about shorts vs opens, but just figured I had misremembered my EM classes, since the professor must be right. Thank you so much for explaining the mental disconnect. I'll sleep better, now that Dr shive and I agree.

@paulshankster

Жыл бұрын

I'm glad I'm not the only one who noticed this. Thought maybe I was missing something.

I wish I would have had someone like him when I was studying to get my Amateur Radio license, I might have accidentally learned something instead of just memorizing the correct answer.

Amazing. So clear and direct. I find the further I go back in history, recorded science lectures seem to just make way more sense than today's classes. I'm not sure why. Maybe they weren't trying to teach so much at once then, and they had a script, so the material was presented in a very logical order, but this is definitely easier to understand for me than a lot of more modern videos that seem to just "wing it".

@bradleysmith681

7 жыл бұрын

Agree. These basic videos are explained step-by-step with the goal of understanding.... Today's videos seem to focus on flashy presentations but lack clear instruction...

@Jasonificatiation

6 жыл бұрын

because nobody teaching those classes knows it from the ground up unless you go to MIT.

@johanponin1360

6 жыл бұрын

A lot of them (military analog computers comes to mind) had a very interesting non academic, non ceremonious yet charmingly vintage in style. Probably as good as a MOOC :p

@fatpie2.0

6 жыл бұрын

I was wondering the same thing. It is more to the point and informative than most videos.

@whippoorwill1124

4 жыл бұрын

The explanation's rather simple I believe: it's laziness. It takes real effort - persistence, thoroughness, time - to produce instruction of this quality. That's been replaced all too widely by superficiality, glitz and the desire to be considered clever without the requisite work to become clever. What's one of the most common complaints about KZread tutorials? Too much attention paid to background music. Dr Shive's teaching is devoid of such frills - and brimming with evidence that he really knew what he was talking about and went to considerable lengths to communicate it effectively. The same's true, for example, of w2aew's KZread videos and content from the Khan Academy. There are no shortcuts to excellence.

As an old-school extra-class amateur radio operator, I recommend this video as an aid to understanding feedline/antenna matching.

I have been getting into ham radio over the past three years and this video is one of the most helpful things I've found in my learning journey.

This film is precious! The mechanical analogue equivalent is the perfect medium to explain concepts like impedance mismatch and standing waves. It is easy to see the mechanics by which a high SWR can destroy the output stage of a transmitter.

Information is sliding so pleasantly and efficiently into my brain! So much respect for this era of engineering.

look at the smile on his face when he talks through the megaphone.

Multiple "aha!" moments, absolutley Priceless!!!!!!

7:30 is the visual demonstration of how a standing wave forms that I’ve been wanting for so long

The reflection formula at 18:15 made my head blow up. I am unable to continue learning wave behavior as my... well..... my head is gone.

WHO WOULD DISLIKE THIS!?

I remember teachers like this as a child, pleasant, refined, disciplined, and often very conservative. They did not suffer fools lightly. It is a sad reality that the ability to calculate in mathematical terms is extremely difficult for so many people. The best way to counter this condition is through constant repetition. Practice practice practice from a young age, as soon as possible. The torture of that exercise will pay huge dividends later in school. So many geniuses become lost in this struggle, the old left brain right brain argument. Matching the imaginative dreamy brain with the analytical is another form of impedance resulting in miraculous new innovation. Happens every time.

@fisicacomsotaque822

3 жыл бұрын

Repetition may help to memorize but what's generally missing in the first place is meaning. There is a generalized use of mathematics in a meaningless approach. That may be the bigger problem. Meaning may though depend on earlier non symbolic early experiences... Diffcult subject! They are many discussion in this direction in Education in Mathematics but this subject of research is not in an very advanced stage.

@Gladiva19

3 жыл бұрын

Its funny how entitled Incels who think they're better than everyone else spread to every corner of the internet event the education part 🙄 This comment shows a clear lack of understanding how social systems generate behavior.

@JohnnyWishbone85

3 жыл бұрын

I don't know what you're talking about, but it has little to do with this video beyond the one minute or so where he's working at the blackboard.

@RuthvenMurgatroyd

9 ай бұрын

@@Gladiva19 Entitled incel?

A picture is worth a thousand words, it is said. This demo of SWR is worth a million. I am an amateur radio operator, and thought I understood SWR in transmission lines. I certainly understand it a lot better now.

This is so much more than clear, concise education: It's poetic. Absolutely amazing.

@projectartichoke

Жыл бұрын

Yes! It's truly a thing of beauty like a priceless piece of art.

We just don't have awesome professors like this anymore. I could listen to this guy for hours.

This a great video .Truly a treasure. A slight correction would be that the free end of the mechanical system is analogous to an open circuit in an electrical system. While the restrained end in a mechanical system is analogous to a short circuit in an electrical system.

@thomaskragerud8039

3 жыл бұрын

@John King Thanks for clarifying

As I get into amateur radio, KZread brings up these beautiful old educational shorts that demonstrate concepts so succinctly and accessibly. I'm so lucky to live in this age for the accumulation of information that's been possible with the internet.

This is such a wonderful and very visual explanation of the basics of waves. Thank you for preserving this awsome content and making it accessible!

this video is so addictive, the more you watch, the more you like

Absolutely fantastic description of waves, impedance matching and SWR! As a radio amateur, this explanation is wonderful. Thanks for sharing!

This is a great video. Clear and well organized and the physical machine really shows off the concepts easily.

This is so much better than any explanation I've encountered in many textbooks.

I've known about most of these concepts for decades, but now I have a real understanding! This is an amazing film, and Shive is absolutely brilliant in his capacity for imparting knowledge.

Best demonstration of wave behavior that I have seen so far.

This has to be one of the greatest lectures of any kind that there can be.

It's a fantastic presentation - very clear, concise and to the point -

This is gold. I am amazed how the concept of impedance can be applied to so many things at once and how waves are all similar in their nature. I went from having no deep understanding of waves to seieng patterns between different physics areas in one video.

One of the best videos /films I have ever seen in my life !

This video is one of the best that mankind has to offer.

Exceptional tuition and understanding by a most clever man.

This video is gem. The best explanation of standing waves I've ever seen

this channel has become one of my favorites on all of KZread, and why youtube is so amazing. i'm one of those math-challenged liberal arts majors (lol right) but i found the UNIX video *really* cool as a backgrounder on computer science in general as well as UNIX, coding etc etc. this vid is incredibly educational as well. awesome stuff, ATT.

this is a superb demonstration and lecture on the general topic

Watching this in 2022 and it's still extremely useful and clear with building an intuition of transmission lines.

Wish I had this guy as my teacher! Great video!

Old True school of amazing physics it must be incredible to have such a fantastic teacher at least once a time in life, this can change the mind and the way of thinking physically for ever.

A guitar string has a standing wave ratio of infinity, and gears and levers are impedance transformers promoting the transmission of the energy of motion . Just two of the many things I've learnt in 26 minutes watching this lecture.

This is so amazingly clear and easy to understand!

Genius is making the complex simple. What an amazing guy. We are very fortunate a small piece of his knowledge was captured on film.

I wish I'd seen this a few times at college! I could have progressed a lot farther a lot quicker in my career with this Gentleman teaching.

Wow-- what a terrific explanation. Every instructor could learn from his relaxed but deliberate pacing-- gives the student a moment to reflect on what he's saying. For anyone wanting to learn more about what an amazing place Bell Labs was, I really enjoyed Jon Gertner's book.

Amazing Amazing Amazing !!! The examples by Dr. Shive are way better than today's 3D & digital simulations !

Very informative and well presented. But I think I noticed something possibly incorrect. At about 5:48, the speaker mentioned that in an electric transmission line, an open end results in a reversed polarity returning wave, and a short circuit end results in a same polarity returning wave. In another KZread video I viewed, "Tektronix - Transmission Lines", the opposite was demonstrated to be true using an oscilloscope. Which is correct?

@briansauk6837

4 ай бұрын

You are indeed correct - the short inverts the wave. Would be a neat trick if it was the other way.

thanks a lot for the perfect analogy. For years I was struggling to understand the propagation of highspeed currents in the circuit boards with different loads.

A great explanation and a stylish presentation! Really enjoyed this.

Thanks a lot for this amazing video. I love that wave model! Very creative idea.

Absolute genius. Masterpiece

Simply Brilliant.

Remarkable outstanding presentation! imho Very Thanks and Very Well Done to this exceptional teacher (to his memory of course).

Incredibly good explanation for how SWR works!

Nice demonstrations of mechanical 1/4 wave and taper matching elements.

surfs up Waves awesome dude. Maximum shear occurs at nodes in structural analysis. FEM today makes this much easier to calculate. Awesome film Thanks.Shalom

This video is a true gem

Really thought provoking. Excellent.

amazing. great job wherever you are man

Excellent point about studying an area that deals with waves extensively allowing you to understand any other area that where waves are fundamental to the field; absolutely agreed. Particles and waves are what everything eventually comes down to.

Thank you for posting this.

10:51 "impedance" being the ratio of "cause" to "effect" 21:00 It's true, our world is abound with these examples! 26:57 was an insightful remark from Dr. J.N. Shive, "Waves of all types behave alike."

I remember seeing this film ... High School electronics class I think. Great subject .... Goo d presentation!

Excellent demonstration.

(May 2023) - This professor is a passionate GENIUS!! Why have I never heard of this teacher/clever demonstrator before?!

good advice! This is ehat I did as I work on shortwave frequency that I can only mesure with my oscilloscope I decided to experiment also with light and audible frequency as they all behave in the same way but it is easier to understand them when actually we can experience them by hearing or seeing (like sound or visible light) .

At 05:09, I think that load impedance is not correct: positive reflection happens on open circuit (not short circuit), and negative reflection happens on short circuit (not open circuit).

@mangelozzi

4 жыл бұрын

He should explain it with regards to Voltage (not Current). I.e a short circuits does not allow the voltage to change (fixed side), whereas the open circuit allows the voltage to change (open side).

@paulshankster

Жыл бұрын

I noticed that too.

At 5:58, there is a mistake on the chalkboard. If the transmission line is shorted, the voltage reflected will be inverted. This is because the current will flow on the minus terminal momentarily during the return propagation time before the output is zero due to short circuit condition. Otherwise, this is a very informative video.

@badgereclipse

5 күн бұрын

I thought that too. I don't understand how they made this mistake though?

Thank You AT&T Channel

May you rest in peace. I deeply appreciate all the knowldge and the laugh. I needed both.

Brings back memories of the Newton's Cradle I had on my dresser as a kid. A visual reference of the physical characteristics of things that occur and can be seen throughout the natural world around us. I want to build one of these machines. It would be great at parties. BRILLIANT!

Beautiful handwriting and drawing.

Plz add such type of videos on voltage, current etc.

Very informative. Thanks for posting this!

BEST VIDEO EVER teaches alot which universities cant teach in 6 months

Really enjoyed ! Impedance matching looks so simple and effortless...

Love the use of big fractions fractions at around 18:35. When I was in school, oh so long ago it seemed perfectly intuitive for me to use =>1 fractions. I was told that this was wrong, somehow -- though my work was accurate, correct, documented, and mostly legible, I tended to skip the needless reduction of fractions at every step that they expected it of me. Conferences were held, admonishment was dolled. I now feel vindicated by this verification that there is no shame in expressing a number as "seven halves," as everything presented in this film is perfectly cromulent and expertly explained. Thank you.

@kered13

6 жыл бұрын

What did they want you to use, mixed fractions? Mixed fractions are almost never used in math and science because they make arithmetic harder.

@debtminer4976

5 жыл бұрын

@@tarmil Know this is old, but your observation makes sense. We Americans use the imperial system, so ''improper'' fractions have a good deal of practical use to us.

@allthingsharbor

5 жыл бұрын

Ditto, Adam Perry...loads of arguments and discussions with mathematics teachers in high school. But the methods taught to me by my engineer father worked best for me! As long as my answers were correct in the end....

Very good demonstration !

I love this. It's so awesome I have no words.

Best explanation of swr I've ever seen!

Excellent explanation that gives a lot of insights.

This is great. Thanks for sharing.

Excellent talk.. Very interesting... Thanks for posting.

Such films are very useful for everyone

really great, thanks for sharing

Wow, that was the best explanation of resonance and SWR I’ve ever seen or heard. Where’s the subscribe button.......

Responding to +HitAndMissLab comment from a few years ago . . . This video also gets the acoustic wave reflection wrong (kind of). The reflection of a acoustic displacement wave from a free end is upright, while the reflection of an acoustic displacement wave from a rigid closed end is inverted. However, we don't typically measure displacement waves for acoustic sound waves. Instead our ears and microphones respond to pressure instead -- and pressure has phase quadrature (90 degrees out of phase) with displacement. So, the reflection of a pressure wave reflects from a free, open end is inverted, and the reflection of a pressure wave reflects from a rigid closed end is upright -- the opposite of what happens for a transverse mechanical displacement wave.

What an incredible video!!!!

To see what I didnt know was called "superposition behavior" at 9:00, see the video "A perfect standing wave in a computer-controlled wave pool". This video is very short, and a bit hypnotizing

Marvelous!

Excellent lecture!

Damn, this guy is good. He did this all in one take?!?

physics always enlightening me.

Excellent. Hi is so enthusiastic :) That's how knowledge should be shared.

Really awesome vedeo........practical feel ...❤

Great video!