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What is the size of the mp4 file?

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W7BE Bob

365 MB

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This email has been checked for viruses by Avast antivirus software.

So it was :-)

My apologies.

Regards,
Gregg
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VE6WGM

Barry Thank you for that wonderful line " Each time I give this talk, I
learn more about what the hurdles are. I find, as a teacher, we can "say
the words and answer multiple choice exams without any REAL understanding".
I took out a lengthy period and left the Audio Engineering industry and
started teaching Electronics & Sound Engineering to Level IV. The first
book I read in preparation was Isaac Asimov's Guide to Science. I always
had in my mind... "What happens if that kid at the front asks "Yeah but
really Why???".

I've only just found this topic after Googling to see if Barry's talk was uploaded to YouTube or not. I watched part of his talk on Long Island CW Club, but unfortunately it would have over-run. He explained things brilliantly, so it's great that you've posted your slides as a PDF.

73
Trystan G0KAY

Hi Trystan
This is Barry.
I've given what I would call a Beginner's Guide to the Nano VNA talk now ten times.
Each time is different, in that I see where folks "lose" a concept.
So the next time I try to insert a slide or two that gives some reference.

Folks do not in general understand what causes REACTANCE in a dipole antenna, nor do they understand that a wire antenna has multiple resonances. I decided to go to a more common analogy: pushing a child on a swing. Even young kids "know" when grampy needs to push them -

"Grampy - push when I am at the end of the arc, when my velocity is zero. Then your push will be in-phase with my natural resonance, and my amplitude will increase. YEAH."

Of course, the grandkid swinging is like the current on an end-fed dipole, and grampy is the feed line, giving the push to the electrons. We can ALL understand that mechanical analogy of "resonance". If the timing (phase) is wrong, then the antenna has a REACTANCE. Pushing the grandchild on the swing too soon or pushing too late causes a problem - we can call these capacitive or inductive reactance - but these are just names. What is the root cause of the problem anyway?

How do we prevent the feed line from pushing at the wrong time??? Can we correct this phase issue by a better "match" at the antenna? How can this little Nano VNA gadget help?


The Nano VNA as a piece of hardware is very complicated..... just like an EKG if you try to make sense of it (and I do each time I visit my crdiologist, much to his delight).

If you already have a pretty good basic understanding of why an antenna has resistance, reactance, impedance, resonant frequencies (yes, plural) and know what PHASE means, then this is just one cool gadget. For under $100 you can take all kinds of measurements over a variety of HF, VHF, and now UHF frequencies and examine multiple graphs at once on software such as VNA SAVER (fantastic).


I do not think any of my talks are posted on youtube, and actually, I would not want that.
I'm not a trained RF Engineer, and with each talk, there are some errors I make (often the engineers point these out at the end of my talk, or to me personally). That's great. I learn as I go.


I think I can give a pretty good 8th grade version of How a VNA Works now.
Just like my cardiologist says I have an 8th grade understanding of my EKG.
He says I need to concentrate on PHASE, not AMPLITUDE of my EKG.
I can say the same about interpretting your antenna's Smith Chart, or R,X,Z graphs.

It's fun learning with each presentation.
If you really want to understand something, try teaching it to someone else.
I've been doing that as a Physics teacher/professor for almost five decades, and by far, my greatest challenge in my teaching career was teaching 9th graders basic fundamental physics with no more math than some simple algebra one.

De Barry Feierman k3eui
Phila region