Antenna Briefs 7, Part 2 - Radio Wave Reflections in Propagation and Antenna Design

This is the second half of episode 7 which shows how reflections are important in radio / wireless wave propagation, and in the design and construction of antennas as well. Part 1 overviewed both, and touched on related effects including refraction, diffraction, absorption, and scattering. Part 2 (this video) provides some key theoretical background concepts showing how reflection occurs and then presents real-world measurements of reflection and absorption / attenuation caused by typical materials found in building construction. We also repeat Hertz's original experiment using modern TinySA instruments and a household mirror. In both videos, the focus is at frequencies of VHF and above, including cellular radio bands. However, much of the material is applicable at HF as well.

[@dominicestebanrice7460]

Simply FANTASTIC content. Thank you! The EM spectrum is SO fascinating.....a window we can see through yet inhibits UV & IR and is essentially opaque to radio.....how fascinating.

[@feeatlastfeeatlast5283]

In four words or less, rate this video series - "This is GOOD stuff."

[@MegawattKS]

Thank you !

[@acestudioscouk-Ace-G0ACE]

You make this stuff so easy to understand... even for this 70 year old who has spent a lifetime in the arts because he failed Physics and Maths at school. I so wish you had been my teacher back then! As for the Corvette, one of my dream cars!

[@MegawattKS]

I waited till my 60's to get that one. Wanted to relive driving a manual. Wow - the ZF6 transmission in the '92 is awesome. So much better than my 3-speed 60's GTO :-)

[@acestudioscouk-Ace-G0ACE]

@@MegawattKS Very nice car! Here in the UK we don't have the roads to do them justice. I gave up sports cars and now I'm 70yrs, I'm happier with my classic 98 Range Rover.

[@W1RMD]

I love seeing this science in action! You may find this fascinating as well. "AT&T Archives: Similiarities of Wave Behavior (Bonus Edition)" The misspelling is in the linked title of the video.

[@samadams6487]

Reminds me of my electromagnetic classes years ago. Of course the reason why there's no e field in the metal is because the electric field is negative the gradient of the voltage. In a perfect conductor the voltage everywhere is equal and so the electric field is zero. I remember the boundary conditions as well in the mathematics for that lots of good stuff. Electronics and antenna design and I took an intended design theory in college at the University of Lowell back in the 80s, is Now useful to me only in my hobby as an amateur radio operator. As I said good stuff you got there

[@scollyer.tuition]

This is a very enjoyable series. Thanks. I'd just make the point that I for one would not be averse to your covering substantially more theory in your lectures - maybe you could revisit some of this from a more theoretical POV in a separate series?

[@MegawattKS]

That's a good idea. Maybe I can do a few "Appendix" videos with the theory plus math at the end of the series. I experimented with including a little in Episode 6, but KZbin analytics shows that about 1/3 of the audience stopped shortly after the derivations began. Math is literally a foreign language, so that's understandable and I've tried to avoid it whenever possible. But for something like the Fourier transform relation between aperture antenna field distribution (for dish antennas) and the far-field patterns, it would be nice to show. Thanks for the feedback.

[@samadams6487]

Good stuff

[@MegawattKS]

Thanks !