- Видео 3
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Doug LeBlanc
Добавлен 24 янв 2012
Science Videos
Antenna Theory Bandwidth
The National Film Board of Canada for the Canadian Air Forces - Great explanation of Bandwidth
Просмотров: 28 042
Видео
Antenna Theory Directivity
Просмотров 57 тыс.7 лет назад
The National Film Board of Canada for the Canadian Air Forces - Great explanation of Directivity
Antenna Theory Propagation
Просмотров 347 тыс.7 лет назад
The National Film Board of Canada for the Canadian Air Forces - Great explanation of Propagation
When people where forced to plan and draw animations by hand, they really needed to be creative and had the time to conceive such intuitive representations of highly abstract concepts. There are few modern hack-together-the-easiest-animation-your-software-enables-you-to videos that are as informative as this one.
Simply the best.
Old videos just never fail to completely elucidate my confusion.
Always the best to start learning from the simplest and the most basic.
Wow, this is both confusing and boring at the same time. As a Ham radio operator, I'm glad I gained my practical understanding of antenna design and propagation from the ARRL Handbook & Antenna Book which both seemed to make perfect sense.
Even today, October 2024, this is a very educational and well presented video. No fancy graphics or animation. Every EE student should view this video!
Now I totally get this topic. Videos like this are brilliant.
Brilliant I did an RAF course on ground wireless as a boy entrant in the 50's of course we had no video at the time. Photon energy transmission is the same mechanism and this illustrates that principle. The wonders of resonance from the breaking wine glass to a CO2 molecule?
This video is really great! I like the way that they leave space and gives the viewer time so that the Info sinks in.
this one is the best and the simplest explanation & demo of the subject
if you coming here from LinkedIn studying 350-401 in 2024 hit the like button
on dipole electric and magnetic standing waves has 90 degrees phase difference. but propagating electric and magnetic waves has no phase difference. why and how?
as i understand shortly. propagating h (magnetic) wave produced by dipole electric wave, so they are in phase. since changing e fields produce magnetic field at the same phase. from this video maybe we can say whenever e and h waves at 90 phase difference, they produce propagating em waves at the same phase.
Hello sir We need more videos on the antennas📡
Man, the very best explanation, in years. Now I understand. Thank you!!!!
4:37 sytyttää tupakan 4:41 ensimmäinen uloshenkäys
🤭👍
I’m very grateful that you’ve uploaded these. They’ve helped me tremendously with my aviation theory exams.
"the traveling wave is in time phase and space qudrature" What does time phase mean in this context?
My hat is off to those animators, doing it way before we had easily generated computer graphics.
Too right!! They color coded stuff as well. There are things here that more recent animators should really learn from!
For this next 1x 40 minute period ...
Nobody needs this crap
Im still learning....it will make sence soon
@ 0:32 Brilliant in its simplicity, haha
Do I need to be licensed to translate to Spanish? I noticed that there is no text in the video, which made me think it would be an excellent pedagogical tool.
Please reach out to library-archives.canada.ca/eng/collection/basics/Pages/who-we-are.aspx
@@Bonkers01 Thank you for the advice!
@ 0:47 A STATIONARY POINT-SOURCE DOES NOT EMIT EM-RADIATON.
3 videos only!??!? With such high quality of education, we want more! ❤❤❤❤
Today's videos are just a pile of no use compared to this gem!
Just a basket of 💎💎💎💎💎💎💎💎
👍
Welp....time to get serious...
Still dont get why first the the E and H field are 90 degrees out of phase but suddenly they are in phase 😢
Yah i am thinking this also that they should be 90 our of phase
1:04 - it should be noted that this visual representation is not a sign wave form but momentary pulses as it does not fade in and out. Indeed, radiating from one point wouldn't have the dynamic of traveling along a radiating element, so that doesn't mean it is necessarily incorrect, just not representative.
1:43 While electrons do move it is not the electrons themselves that are moving this distance but rather their electrical field, similar you could say to how a wave travels across water though the actual specific molecules of water aren't traveling the full length of the wave's propagation.
👍
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Even grade 10 students will be able to understand from this video. Hat off 🙏🏻🙏🏻
What an amazing video. Such types of animated videos are really helpful to understand different concepts. Thank u so much
I was definitely thinking an episode of Tom and Jerry was about to start after that intro..
2:30 can we actually imagine it as squeezing electrons? Aren't they in similar distances all the time?
These type of videos explains the best. ❤
This video turned my life around.
Man, old dudes must use 100% mind power and 100% effort, creating such billiant people.
I am not as impressed by this film as most other viewers seem to be. There are two major shortcomings: First, the question of why the "pulsating" electric and magnetic near-fields around the dipole travel out into space is not addressed. Instead, at 5:10 they weirdly move the "field of view" away from the antenna and just claim that there is indeed propagation with E always being perpendicular to H (which, of course, is true, but for somebody without prior understanding of electrodynamics, is not evident why that should be at all) Second, when they "explain" reflection at surfaces, they simply state that the E-vector is instantaneously reversed, while the H-vector is not (8:06). For someone who is not an expert (and therefore the target audience of this movie) this seems completely arbitrary, and no explanation is given as to why. So yes, the film is good in parts, but unsatisfactory in others...
In this diagram animation BOTH the VOLTAGE and CURRENT (fields) are drawn as strongest in the middle of the antenna. As far as I know one of them should be stronger at the tips of the antenna and the other weak at the tips but strong at the feed points.
I think it depends on the wavelength relation of the antenna and where the feed point is. I recently saw a video that illustrated your exact point, but I'm trying to remember what was said. I found it by accident. I feel like it had to do with an end fed antenna, made at a fractional wavelength and showing why a center fed dipole is so desirable, but an end fed (while more practical in building and mounting) is a compromise electromagnetically. I think it was regarding building a 160m antenna. The guy was explaining the trade offs and difficulties in building such a long antenna for that band.
Not so - at 3:34 we see the current at one particular instant with a maximum in the center, and with minima (=zero in a perfect antenna) at the ends. Just a few seconds later, at 3:40, we see the voltage curve at that same instant with a minimum at the center, and maxima at each end. This is precisely what one would expect of a 1/4 wavelength conductor cut off at both ends - it is impossible for current to flow at the ends, so the current is low (=0) there, and the voltage must therefore be high there. To underline this, the commentator says "This current standing wave is 90 degrees out of phase with the voltage standing wave." Try watching it again.
Bullshit!
O.k
My marriage was on the brink of collapse before this video cured my wife of wokeism. Thank you so much Canada
I love this, I knew this should be this ease unlike the way my lecturer thought us.
now all it needs is more title screens and dramatic music
Beautiful! Isn't it!
Thank you for Sharing!
Wow