[alancalverd]

What cancels the backwards wave?

The question is not answered, because it is physically meaningless! Maxwell calculates the Poynting propagation vector from physics, Huygens predicts how it will be affected by reflection, refraction and diffraction. As there is no backwards vector from Maxwell, there is no meaning in the back-projection of Huygens.

[alancalverd]

What's the rule for Huygen's geometric construction?

Every point on a wavefront is the origin of wavelets of the same phase and frequency.

[hamdani yusuf (OP)]

Stopping human sacrifice without causing significant change in the weather should be enough.

Human sacrifice pretty well died out in 1800, around the date that climate "scientists" consider to be the beginning of anthropogenic global warming. The facts speak for themselves.

Do you count holocaust as human sacrifice?
How do you define it?

[hamdani yusuf (OP)]

The signal is due to reflection.

The plate is perpendicular to the beam axis, which means that any reflected energy will be sent back upstream, surely? And the pulse is very narrow compared with the cone of the primary beam

Full marks for an experiment that was sufficiently precise  to display an anomaly!

At that distance, the primary beam is very strong, well over the maximum range of the receiver. That's why a very small portion of it can still be detected.

[hamdani yusuf (OP)]

Huygens predicts how it will be affected by reflection,

How is a wave reflected in Huygen's model?
What makes it different than transmission?

[hamdani yusuf (OP)]

What's the rule for Huygen's geometric construction?

Every point on a wavefront is the origin of wavelets of the same phase and frequency.

But every wavelet only consists of a half sphere, instead of full sphere, for no clear reason.

[hamdani yusuf (OP)]

Huygens predicts how it will be affected by reflection,

How is a wave reflected in Huygen's model?
What makes it different than transmission?

Let's not forget about my experiments in my other thread.

I've finished editing a new video on horizontally tilted diffraction. The first part is just fixing my old clips, while the last part contains new material. I'll share it here when I finished uploading it to my Youtube channel.
Many sources say that diffraction-interference pattern in a single slit experiment require the slit to be narrow, and comparable to the wavelength of the light wave. The word comparable in this context is not well defined.
Some of them also mention that the edges of the slit must be sharp.
My experiments will show that they are not necessarily true.

Here you are.

I just got an even stronger evidence that diffracted light is produced by the edges of the obstacle, instead of the space between those edges. The experiment involves linear polarization.

I've finally uploaded the video.

[evan_au]

half sphere, instead of full sphere, for no clear reason.

This accounts for the direction of propagation.

Huygens didn't know about electromagnetic waves, where the interaction of electric and magnetic fields produces a direction of propagation. So he represented the direction of propagation geometrically.

[alancalverd]

Do you count holocaust as human sacrifice?
How do you define it?

Sacrifice involves ritually killing a small number of chosen victims or volunteers in order to propitiate a supernatural being. The victim is usually a chicken or a sheep but for a really good harvest you need to kill a single human.

Mass murder is about politics, not agriculture. 

[alancalverd]

But every wavelet only consists of a half sphere, instead of full sphere, for no clear reason.

Because, for the umpteenth time, it is a model, not an explanation!

If you plot wind, tide and thrust vectors on a navigation chart, you can work out where the boat will be in an hour's time. It's a perfect model but it doesn't explain why the air, water or boat actually move at those particular velocities..

[alancalverd]

At that distance, the primary beam is very strong, well over the maximum range of the receiver. That's why a very small portion of it can still be detected.

Then why is the primary beam not detected at 1:21 or 1:25? Something rather special happens at 1:23.

A lot of scientific progress comes from the investigation of anomalies, and we must be grateful to experimental geniuses like yourself for finding them. The phenomenon occurs over a movement commensurate with your 2.8 cm wavelength, which is why I asked for confirmation of that value.

[hamdani yusuf (OP)]

Then why is the primary beam not detected at 1:21 or 1:25? Something rather special happens at 1:23.

You're confusing because you skipped 0:24

[hamdani yusuf (OP)]

Huygens predicts how it will be affected by reflection,

How is a wave reflected in Huygen's model?
What makes it different than transmission?

Here's how reflection is explained using antenna model, starting at 5:45.

This is the model I used to come up with blocking mechanism, and designed polarization twister.

[alancalverd]

Then why is the primary beam not detected at 1:21 or 1:25? Something rather special happens at 1:23.

You're confusing because you skipped 0:24

No, I watched what happened as you slid the plate from one side to the other. Fairly smoothly and continuously, And something happened at 1:23.

[hamdani yusuf (OP)]

Then why is the primary beam not detected at 1:21 or 1:25? Something rather special happens at 1:23.

You're confusing because you skipped 0:24

No, I watched what happened as you slid the plate from one side to the other. Fairly smoothly and continuously, And something happened at 1:23.

At 1:21, the plate completely blocked the microwave.
At 1:25, the plate doesn't interact with microwave at all.

[hamdani yusuf (OP)]

Huygens predicts how it will be affected by reflection,

How is a wave reflected in Huygen's model?
What makes it different than transmission?

Here's how reflection is explained using antenna model, starting at 5:45.

This is the model I used to come up with blocking mechanism, and designed polarization twister.

There's a substantial difference between the antenna array model and Huygen's model. In antenna model, the wavelets are always originated from an antenna, which must consist of charged particles. On the other hand, Huygen's principle says that the wavelets can originate from vacuum of space.

[alancalverd]

And at 1:23 there is a signal at the receiver.

Don't be modest - you have demonstrated a phenomenon you didn't expect, by very careful experimentation! That is the best science.

[William Hardy]

What I understand is diffraction is bending of a single wave of light around an obstacle,
whereas interference is the superimposition of two waves to form one wave.
difference_between_diffraction_and_interference.jpg (167.77 kB . 590x312 - viewed 748 times)
You can find some detailed differences here: https://dewwool.com/difference-between-diffraction-and-interference/

[hamdani yusuf (OP)]

What I understand is diffraction is bending of a single wave of light around an obstacle,
whereas interference is the superimposition of two waves to form one wave.
difference_between_diffraction_and_interference.jpg (167.77 kB . 590x312 - viewed 748 times)
You can find some detailed differences here: https://dewwool.com/difference-between-diffraction-and-interference/

I found some inconsistencies in the article, where what it says in one part contradicts what it says in another part. I'll point out one by one in following posts.

[Bored chemist]

But every wavelet only consists of a half sphere, instead of full sphere, for no clear reason.

It's interesting to note that you can do essentially the same maths with water waves as with light waves.
And you get comparable results- diffraction, refraction interference etc.

If you are trying to explain the lack of a "backwards" half of the wavelet, you can invoke the conservation or energy and momentum. There is a "clear reason".

What stops you doing the same with light?

Huygens didn't know about electromagnetic waves

No.
In his day they would have said that they were waves in the luminiferous aether.

The stuff doesn't exist but if you just want to calculate the propagation of light waves, the aether model works.