When I was studying for my ham radio exams, and didn't understanding something, this was to place to come.

Yup! Forrest Mims "Engineer's Mini-Notebooks" - Fun circuits, well drawn - just like Alan's!

Ditto very good instructor. Wish my electronic teacher back in school was nearly as good as this fellow. Our guy was horrible.

You should consider using it in conjunction with a PC and nanoVNA saver; this will allow you to use practically arbitrary sweep point setups with more accurate averaging capabilities.

You know, it strikes me that RF is *very* similar to audio engineering, but combined with core EM principles. In my 10 years of professional work in audio, I came away with a primary insight: the most important element in getting a good recording is the room itself. "Room acoustics" deals with things like cancellation of standing wave modes and problematic reflections. So anyway, just a tidbit for folks that are technically interested in audio; you can make the leap into RF stuff no problem because it equips you with the core intuition, very very nicely.

@@danmoretti8898 It is! Also the same as, say, engineering a car's suspension. Those pesky waves show up everywhere :) I think the main thing that's different with audio is that you very rarely have to worry about transmission lines so much because the wavelengths are huge relative to most of the parts. Audio synthesizers specifically have a lot of concepts in common with radios and are a good place to start learning the concepts because the components needed and test equipment requirements are far lower and less expensive.

​@@bundo13 ​ Cheers! As you would imagine based on your example of the car suspension, there are plenty of energy buildup problems in audio! The rest of my post here is probably stuff you could have guessed, but I wanted to share anyway. As a rule in audio, transmission issues come into play anytime transduction occurs. So 1) capturing audio (particularly in stereo) and 2) playing audio through speakers. In the former case, phase coherence becomes a really important thing to have a handle on with mic placement. In the second case, we often run into problems with resonant cavities (rooms). If your room is too small, it becomes a high pass filter due to bass frequencies not being able to fully propagate through a cycle. This makes for a dishonest mixing environment, and your mix will sound weird on playback in most environments. HF buildup is a huge problem in small rooms as well. In auditoriums, propagation rates begin changing in a manner that's thermally dependent, which is why live sound sucks for the first couple of songs. The crowd brings a substantial amount of heat. Until thermal equilibrium is reached, the EQ is completely off. So anyway, longitudinal transmission through a gaseous medium is really where transmission stuff gets wacky. Between synthesis; microphone placement; mixing; and live acoustics, audio engineering is a very broad and interdisciplinary process. But again, its just the same as any other type of engineering in that sense.

@@danmoretti8898 Fascinating! Thank you for posting all this, I am certainly no expert in audio or RF but I learned at some point to post what I think I know on the internet because writing it out helps me solidify it in my own head. I should have clarified that I was thinking of the electronics. Audio frequencies propagating at very high speeds in electrical circuits have huge wavelengths, but can certainly come into play when at the speed of sound in air. So I think that reflections and other transmission line effects can mostly be ignored when designing the electrical side. Not to say the electrical side is trivial of course, just different things that are the big factors in overall quality. I have to admit the first thing I was learning about where I feel like I really started to get a handle on wave math was when I was learning about transmission line speakers, because they're just so darn cool. I found it much easier to imagine speakers and sound waves when thinking about stuff because those things are so much more familiar in our day to day lives. I often think about antennas as speakers and impedance matching circuits as horns still! I also use these as analogies when trying to explain what I think I know to other people as well. I find it much easier to imagine how a shout echoes off of a cliff wall than about how an electrical signal reflects off the end of an open transmission line. So I appreciate your examples, I've never messed with audio design at such scales. It's very interesting, and I feel like the more ways we have at looking at the same fundamental concepts, the better we can understand it. Interesting tidbit is that Bose has even worked on electromagnetic dynamic suspensions for cars. I may not always agree with the value prospect of Bose's products, but I've always respected their engineering!

@@bundo13 Cheers, I feel the same way about writing or sharing these concepts aloud! Much appreciate the opportunity to nerd out, my friend.

Sounds like we have the same past. I loved Oki. Did the whole UMUC thing too.

you could always just normalize to a 75Ohm load during calibration to get around this, but the firmware isn't setup to tell you the correct calculated impedances from this normalization. If the NanoVNA firmware developers are reading, a feature to change the impedance normalization of the chart after calibration or before the calibration so the calculated impedances would be correct would be great.

They are evolving so quickly eventually SOON a NanoVNA will do what an 8753ES will do, which costs 7-8k used in ok condiiton. Once they have a reversible test head it'll allll be over.

Silas Marner considering the price point, the nano VNA offers value for education, and hobby use. However, the performance doesn’t come close to a 8753 or a field fox: span, dynamic range, points, coupler,....

I'll try to do more of them with future videos.

Thank you sir! I’m an old timer and this menu driven stuff is a little different. My HP 8921a is bad enough. I’m trying to keep up. Haha.

Thank you - I hope you enjoy my series as you work through them, and please excuse the poor video quality and shaky cam on my early videos. I do talk a bit about complex impedance in later videos. Note that the definition of resonance is the lack of reactance (only resistance). Resonance does NOT always mean 50 ohms!.

yes it can - maybe in a future video.

A little powerpoint animation recorded into a .gif.

@@w2aew Doesn't matter how it's done , important is content , everybody see the main principle. Really great!

The electronic tablet I am using is from www.remarkable.com

I've double checked the VNA a couple of ways (with a professional VNA, as well as using TDR techniques and other measurements. I'm confident in the results I showed. Are you sure you properly accounted for the velocity factor of your transmission line?

Yes it can help a tuner work better, because it does change the impedance looking into the line

If you have no idea of the length, simply start with a low frequency, maybe 30 or 40MHz, and then work your way up to get better resolution.

From what I've found in the manual on page 14, it seems that this technique should work for any type of transmission line. A single open wire is more of an antenna (radiator) than an actual closed field transmission line kinda device (think twin lead cable), so I don't know how well that would work, but I might try using this technique on some microstrip, twin lead, and twinax lines in the future just to see how reliable this method can be. It might be difficult to source a VF figure for some more obscure line types (like twinax), but it would be cool to experiment regardless.