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Nano VNA BASIC WORKSHOP via Zoom

 

The ¡°Five County Digital Training Net¡± (Philadelphia region) is hosting a series of Zoom Workshops on Monday evenings at 7-9 pm. The topic: Nano VNA Fundamentals
All are welcome to join.
Link:

We have already held two sessions covering the fundamentals of what a VNA is capable of measuring and the second session covered how to CALIBRATE the VNA over a frequency range.

The 3rd Zoom session on November 14th will cover what a Nano VNA measures and what it calculates: the forward and the reflected signals are compared (S11) and the following are calculated:

1) Reflection Coefficient (rho) - a fraction from 0 to 1.0 representing the ratio of returning signal to incident signal. In an antenna, you do not want any reflected (return) signal, so the ideal reflection coefficient is zero.

2) Return Loss (dB) - this is based on the reflection coefficient and represents the loss of signal, but measured in decibels (dB) rather than as a percent or fraction. Hams rarely use this measurement. Why?

3) SWR - standing wave ratio - We all use this term but what does it mean? What is an ¡°acceptable¡± SWR in terms of antenna performance.

I will tie these three measurements into what a Smith Chart reveals.

Come join the discussion.
I am not an RF Engineer - so I try to keep this at a moderate level of mathematics.

De k3eui
Barry (k3euibarry - at - gmail.com)
Five County Digital Net manager
Philadelphia PA
November 13 2022
 

Hi, Barry,
Did you happen to record those previous sessions?
Thanks,
--Kirk, NT0Z

My book, "Stealth Amateur Radio," is now available from www.stealthamateur.com and on the Amazon Kindle (soon)

On Sunday, November 13, 2022 at 06:21:03 AM CST, Barry K3EUI <k3euibarry@...> wrote:

The ¡°Five County Digital Training Net¡± (Philadelphia region) is hosting a series of Zoom Workshops on Monday evenings at 7-9 pm. The topic: Nano VNA Fundamentals
All are welcome to join.
Link:

We have already held two sessions covering the fundamentals of what a VNA is capable of measuring and the second session covered how to CALIBRATE the VNA over a frequency range.

The 3rd Zoom session on November 14th will cover what a Nano VNA measures and what it calculates: the forward and the reflected signals are compared (S11) and the following are calculated:

1) Reflection Coefficient (rho) - a fraction from 0 to 1.0 representing the ratio of returning signal to incident signal. In an antenna, you do not want any reflected (return) signal, so the ideal reflection coefficient is zero.

2) Return Loss (dB) - this is based on the reflection coefficient and represents the loss of signal, but measured in decibels (dB) rather than as a percent or fraction. Hams rarely use this measurement. Why?

3) SWR - standing wave ratio? -? We all use this term but what does it mean? What is an ¡°acceptable¡± SWR in terms of antenna performance.

I will tie these three measurements into what a Smith Chart reveals.

Come join the discussion.
I am not an RF Engineer - so I try to keep this at a moderate level of mathematics.

De k3eui
Barry? (k3euibarry - at - gmail.com)
Five County Digital Net manager
Philadelphia PA
November 13 2022
 

Kirk
No, I did not record them because I wanted to encourage questions/comments and when you record these sessions,
(some) folks are hesitant to ask questions or respond.
Barry
 

Nano VNA graphs using VNA SAVER

Lots of folks have asked me how the REFLECTION Coefficient S11 graph, the RETURN LOSS graph (dB) and the SWR graph compare.
Basically they all show similar aspects of the antenna.


This trace around the 80m band, and is AFTER my CLC Antenna Tuner - set up for min SWR around 3600 kHz
The antenna is about 30 ft high, 130 ft long, center-fed with RG213 coax.
It is a great NVIS antenna.

Note the similar shapes of the RETURN LOSS (dB) and the SWR curve (both derived from the reflection coefficient (S11)


de k3eui Barry

November 13 2022

80m dipole post TUNER 4G6 Nov 13 2022.jpg

 

This is what I see with the NANO VNA standard LOAD (50 ohm dummy load R)
Nothing unusual here.

de k3eui Barry

50 ohm dummy load 1 to 30 MHz.jpg

 

oops
here is the much better Dummy Load trace

Barry k3eui

Dummy Load 50 ohm 1 to 30 MHz.jpg

Doug
 

Hi Barry. This sounds like a really invaluable project. It is just too bad that we didn't know about it sooner, so that we could take in all five sessions.

Is there any possibility that any previous viewers might have copied the first two sessions, or even some screen grabs. I always use PrintScreen to keep a record of any Zoom sessions that I view.

Just a hopeful wish.

Thanks again for your hard work.

Doug

On 13/11/2022 07:20, Barry K3EUI wrote:
The ¡°Five County Digital Training Net¡± (Philadelphia region) is hosting a series of Zoom Workshops on Monday evenings at 7-9 pm. The topic: Nano VNA Fundamentals
All are welcome to join.
Link:

We have already held two sessions covering the fundamentals of what a VNA is capable of measuring and the second session covered how to CALIBRATE the VNA over a frequency range.

The 3rd Zoom session on November 14th will cover what a Nano VNA measures and what it calculates: the forward and the reflected signals are compared (S11) and the following are calculated:

1) Reflection Coefficient (rho) - a fraction from 0 to 1.0 representing the ratio of returning signal to incident signal. In an antenna, you do not want any reflected (return) signal, so the ideal reflection coefficient is zero.

2) Return Loss (dB) - this is based on the reflection coefficient and represents the loss of signal, but measured in decibels (dB) rather than as a percent or fraction. Hams rarely use this measurement. Why?

3) SWR - standing wave ratio - We all use this term but what does it mean? What is an ¡°acceptable¡± SWR in terms of antenna performance.

I will tie these three measurements into what a Smith Chart reveals.

Come join the discussion.
I am not an RF Engineer - so I try to keep this at a moderate level of mathematics.

De k3eui
Barry (k3euibarry - at - gmail.com)
Five County Digital Net manager
Philadelphia PA
November 13 2022





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73

Doug Kearney VA3DKA

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www.avast.com
 

Are there recordings?

On Sun, Nov 13, 2022 at 7:21 AM Barry K3EUI <k3euibarry@...> wrote:

The ¡°Five County Digital Training Net¡± (Philadelphia region) is hosting a
series of Zoom Workshops on Monday evenings at 7-9 pm. The topic: Nano VNA
Fundamentals
All are welcome to join.
Link:


We have already held two sessions covering the fundamentals of what a VNA
is capable of measuring and the second session covered how to CALIBRATE the
VNA over a frequency range.

The 3rd Zoom session on November 14th will cover what a Nano VNA measures
and what it calculates: the forward and the reflected signals are compared
(S11) and the following are calculated:

1) Reflection Coefficient (rho) - a fraction from 0 to 1.0 representing
the ratio of returning signal to incident signal. In an antenna, you do not
want any reflected (return) signal, so the ideal reflection coefficient is
zero.

2) Return Loss (dB) - this is based on the reflection coefficient and
represents the loss of signal, but measured in decibels (dB) rather than as
a percent or fraction. Hams rarely use this measurement. Why?

3) SWR - standing wave ratio - We all use this term but what does it
mean? What is an ¡°acceptable¡± SWR in terms of antenna performance.

I will tie these three measurements into what a Smith Chart reveals.

Come join the discussion.
I am not an RF Engineer - so I try to keep this at a moderate level of
mathematics.

De k3eui
Barry (k3euibarry - at - gmail.com)
Five County Digital Net manager
Philadelphia PA
November 13 2022







--
-Chris
 

On Sun, Nov 13, 2022 at 10:57 AM, Barry K3EUI wrote:


No, I did not record them because I wanted to encourage questions/comments and
when you record these sessions,
(some) folks are hesitant to ask questions or respond.
That is truly unfortunate. I am sure there are hundreds if not thousands of people including myself who would love to watch the presentation, but who got late notice or were not available at the time. How many viewers fell into the category of too shy to participate? Could you not record the session, maybe have a recorded Q&A, and then have a closed Q&A at the end? I only ask because this Zoom sounds like a great thing you did, but for very limited benefit.
I am reminded of school classes where a few students were too shy to speak up in class, and therefore they fell behind, eventually failing the class. If they were lucky there was a teacher who noticed and took them aside, perhaps arranging private tutoring so they would be more comfortable.
 

I have been asked many times if these Zoom sessions on Nano VNA were recorded.
NO. They were not recorded.

The reason is simple: I wanted these sessions to be discussions, not lectures.
Many folks will not ask or answer questions if the session is recorded (from my experience as a teacher/professor).


I will pause during the zoom session and ask folks to contribute (like a live class)
¡°What is reactance in an antenna?¡±
And then ask for contributions.
How do you measure reactance with a VNA from inside your shack (at the end of X feet of coaxial feed line)?

¡°Does SWR change along the feed line if the attenuation is very low?¡±
That one is interesting.
I suggest you read the Walt Maxwell books on SWR and feed lines from QST articles in the 1970¡¯s.


Sometimes (actually often) an open ended question leads to a lively debate!


I have about 200 slides (PPT) that I made over the past three years covering all aspect of VNA and antennas and Smith charts.
I¡¯d be happy to share those, as a PPT or as a PDF file.
The slides are just key points to get a discussion going.

Learning is an iterative process with a lot of mistakes along the way.

Come join in on the presentation/discussion,

de k3eui. Barry
Philly
Nov 14th
 

Hello Barry,

Some of us in the NanoVNA community actually live outside continental USA.
Not sure where your QTH is, but there is also a 5 hour time difference across the continental USA as well.

It would be great to have access to your obvious vast experience in RF topics, especially when it shows the application of the fabulous NanoVNA.

Would you reconsider recording? (Even delay access to encourage as much online participation as possible)

73...Bob VK2ZRE (Downunder in Australia)

On 15/11/2022 12:38 am, Barry K3EUI wrote:
I have been asked many times if these Zoom sessions on Nano VNA were recorded.
NO. They were not recorded.

The reason is simple: I wanted these sessions to be discussions, not lectures.
Many folks will not ask or answer questions if the session is recorded (from my experience as a teacher/professor).


I will pause during the zoom session and ask folks to contribute (like a live class)
¡°What is reactance in an antenna?¡±
And then ask for contributions.
How do you measure reactance with a VNA from inside your shack (at the end of X feet of coaxial feed line)?

¡°Does SWR change along the feed line if the attenuation is very low?¡±
That one is interesting.
I suggest you read the Walt Maxwell books on SWR and feed lines from QST articles in the 1970¡¯s.


Sometimes (actually often) an open ended question leads to a lively debate!


I have about 200 slides (PPT) that I made over the past three years covering all aspect of VNA and antennas and Smith charts.
I¡¯d be happy to share those, as a PPT or as a PDF file.
The slides are just key points to get a discussion going.

Learning is an iterative process with a lot of mistakes along the way.

Come join in on the presentation/discussion,

de k3eui. Barry
Philly
Nov 14th
 

Might I suggest that we continue to meet via Zoom on Monday evenings at 7 pm (EST) to share what we know about the VNA?

I don¡¯t see my talk as a ¡°lecture¡± to record and watch. I¡¯m not a VNA engineer.
But I can see why this technique (record and play back) might work for some who just can¡¯t make the ¡°live¡± session.


We have met three times now via Zoom and discussed these topics:
1) What is a VNA and in broad strokes how does it work?
I compared the VNA to a dolphin or a bat and SONAR - what do you learn from the reflected SOUND waves

2) Why is CALIBRATING the device over a frequency range important - and how do you do that?
The SAVER software makes this process easy - and I can save a file with thousands of data points.


We then talked about
Why an antenna has a resistance, a reactance, and an impedance?
What kinds of graphs can you plot to understand an antenna?
I did a live demo with my own 80m dipole in my yard.


3) Yesterday we talked about some of the VNA guts
Reflection Coefficient (rho) as a RATIO of reflected voltage to forward voltage and why 0<rho<1
RETURN LOSS - what is it, why is it measured in decibels, and why is it a positive value
SWR - how is this related to reflection coefficient and Return Loss

We ran out of time (8 pm EST) and stopped but there were some good questions and discussions.

Might I suggest we continue to meet via Zoom on Monday evenings at 7 pm EST.
I realize that makes it awful for other time zones distant from N.America

I hinted that I could use my own Nano VNA (model 4 H) to help me adjust my MANUAL antenna tuner for HF antennas.
I then showed how the various graphs (SWR, Return Loss) change as I mess with the capacitor/inductor setting in my ¡°TUNER¡±.

So come join in on this discussion of Nano VNA next Monday evening.

De k3eui Barry
Philadelphia PA USA
 

The time didn't work the first time, and nothing has changed so it won't work again.

Steve
W5RRX
Las Cruces, NM
 

Barry,

I enjoyed your talk yesterday evening ..
Next Monday at 7PM is fine with me¡­

Should I use the same zoom invite?

Tnx & 73s

Doug KD4NC

Kennesaw, Ga
 

Good morning Barry

super.... unfortunately I have missed the three sessions ,and this is not recorded I would be happy to share your 200 slides and ask questions . I have experiment with VNA an anything related. I am a retired engineer and would welcome to share some of the presentation from university of liege ( this is in Belgium)
I believe this is in English must check.
again this is a super idea, how do we link with soon the conference and what is the difference in time between your location and Belgium ?

de ONL11812 Pierre
Nov 16th

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