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Comment by gr33nq | Hacker News Reader

Something I've had a longstanding desire to learn about is radio frequencies. I'm a very visual person, but I have yet to find any resource that explains it in a way that really makes sense to me. Especially when you start getting into modulation and whatnot. I'm fortunate to be able to use a variety of wireless technologies at work (licensed 80GHz, 18GHz and 950MHz frequencies), but I admittedly only have basic working knowledge and don't clearly comprehend what's happening at the lower physical level.

Does anyone have a good recommendation on any material that really made wireless technology understandable for you?

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There's no all in one stop for understanding radio but these 5 resources helped me a lot.

The RF Get Down courses. This is by far the best material online to learn RF and how modulation works: https://www.youtube.com/@rfgetdown/videos

3blue1brown's video tutorial on the fourier transform: https://www.youtube.com/watch?v=spUNpyF58BY

AT&T Archives: Similiarities of Wave Behavior http://www.youtube.com/watch?v=DovunOxlY1k

Quadrature Signals: Complex, But Not Complicated by Richard Lyons, https://dspguru.com/files/QuadSignals.pdf https://dspguru.com/dsp/tutorials/quadrature-signals/

Antenna Theory's website and forums, https://www.antenna-theory.com/antennas/main.php

I also highly recommend getting a $20 rtl-sdr USB software defined radio dongle. They're great toys for learning RF, what modulation is, and exploring the spectrum.

A 20$ RTL-SDR will give you a very broad view of the spectrum and an idea of how one area can be quiet, the other filled with signals and the oddities of atmospheric noise, etc. Super fun and there are 100,000 YouTube videos on how to get it working.

https://www.amazon.com/NooElec-NESDR-Mini-Compatible-Package...

I would argue that a $0 web-sdr bookmark will teach you exactly the same things without you forever wondering if it's your antennae that's the problem.

Very true... only issue is that you wont receive any local signals if there's no local web-SDR in your area.

You sort of back-handedly made a case for using your own antenna to better understand radio. :-)

Oh, there is absolutely a case for trying your own antennae, and experimenting with various antenna topologies, to understand radio.

The issue is if it's the first thing a newbie should be doing while also trying to work out if their USB dongle works at all :D

Where do you find these? Is there an online library?

websdr.org has a huge list. You can find a few more via google.

One place to start peeling the onion is amature radio. In the US, see: https://www.arrl.org/

Introduction to spectrum, freq allocation (bands) and modes.

https://youtu.be/DovunOxlY1k

https://youtu.be/-F7KYLO4Bkg

https://youtu.be/ScOd3ExKFM8

https://youtu.be/I9m2w4DgeVk

Hardware to play with:

1) HackRF : https://greatscottgadgets.com/sdr/

2) RF Explorer : https://j3.rf-explorer.com/

You also need to study Physics (Electromagnetics) and Electronics (Communication Electronics). Checkout both popular textbooks and general audience books.

For a absolute beginner a good place to start is The Essential Guide to RF and Wireless by Carl Weisman.