开云体育

Thank you all for the great suggestions. I will modify (correct) the TDR slides. I was fascinated to watch the TDR "work" so well with some old coax I had in my shack, and just googled TDR to see if I could understand HOW it works.

Now.. I am at about a 9th grade understanding of this VNA technology, and I should know, since I taught 9th grade Physics for ten years at the end of teaching high school physics for 41 years (then university levels).

I've looked at the Nano VNA as something that I wanted to "tame" and have had fun learning, reading, playing, and even giving a few talks PPT to local clubs and some not so local to Philadelphia. With each presentation, I learn something new from the questions that pop up.

So no, I am not keen to "record" a presentation, although most of the clubs do record an hour or more for their own membership.

So I am still learning, and maybe in a few more months will feel more comfortable with my live presentations to go out on a YOUTUBE. Confidence grows with each presentation (try teaching 9th graders physics some time).

If you have a local club that is looking for an outside speaker, and can deal with this Nano VNA as a 9th grader, I'm your guy. I am not a professional RF engineer who has worked with VNAs his whole life.

If I can introduce someone to a new tool to have in their toolbox and learn as you go, that is enough for me.

Again, I do appreciate the pros explaining to me where a slide is misleading, or simply wrong.

I like the title now: The Nano VNA: An Antenna Stethoscope
(Like the EKG tells you something about the state of health of your heart if you know how to "read" it.
A VNA is one cool gadget

73
Barry k3eui
K3euibarry@...

Not to be offensive but have verified 3 volt and 5 volt power? LEDs lit>

Now let's go off the deep end -

how do you characterize ferrites and powder iron (rod and toroid) for useable frequency as inductors/choke, transformers, and wide band transformers?

Mike
N9XYP

All good ideas. Clubs are always looking for interesting programs.
Before Covid, our in-person club meeting would sometimes have a guest
speaker “live” via Skype. We have a projector and some speakers to see and
hear the remote presenter, plus a camera on a tripod so the presenter can
see the room. We also have a mic on a long cord to pass around for
questions. For presenters, it’s more work than a one time video, but it’s
much more engaging than watching a video too.
Thank you to all who take their time to share what they have learned, no
matter how they make it happen!

Chris, did you get the PDF version of the measurements? Those are the
final version.

I'd be glad to work with you on how I made the measurements. Many were
made using the HP 7653C and not the NANO. There is only one measurement
set that I can not adopt to the NANOs. Ask specific questions and I'll
answer.

Dave - W?LEV


On Wed, Feb 24, 2021 at 4:53 PM c suddell via groups.io <chrissuddell=
[email protected]> wrote:

Hi Dave,

Would love to have a chat to you about your results. I'd like to
republish your findings, but wanted to chat about how you came up with them.

Chris
M0VUE

--
*Dave - W?LEV*
*Just Let Darwin Work*

OK, was finaly able to get the NanoVNA-H in DFU mode and was able to find it in DfuSeDemo...

loaded the proper firmware DFU file and loaded it correctly as per the procedure...

the unit is still dead!...

While in DFU mode the Blue LED stopped flashing and did comeup in win10 as STM32 Bootloader like it should be...

the DfuSeDemo found the unit, I was able to load the proper firmware even did a VERIFY and confirmed it was loaded.

removed the jumper

rebooted the NanoVNA-H, blue led started flashing again and... wait for it... NOTHING

Just a white screen!

looks to me like the unit is not having firmware issues... instead I think this is a HARDWARE display issue???

comments or suggestions please

73

Richard VE2DX

ok!... Let me be clear... the unit was NOT loaded with -H4 firmware...

The unit was sitting on a shelf for a couple of months and when I pulled it out to use it it was... DEAD... Bricked... NOT WORKING... call ot as you wish it stopped working by itself not because I load -H4 firmware in it...

I tried running the DFU procedure and can not detect the unit, and yes I did follow the process to get the unit in DFU mode holding the Select switch while powering up, tried in all 3 possible position...

No I do not see any Jumplers on the pcb

I got myself an ST-Link V2 from Amazon, and I am simply looking for;

1- Software to download firmware in NanoVNA-H (Not using DFU!)
2- Proper site do download latest NanoVNA-H Firmware HEX file.
3- good site for step by step of the procedure

thanks for the help

73

Richard VE2DX

On 2/24/21 9:06 AM, Larry Macionski via groups.io wrote:

Barry K3EUI-
I appreciate your dedication to bring this effort to the group.
Obviously there is a Power Point version. You will be in demand when hamfests, return Shortly.
I encourage you to narrate a Power Point Presentation and place it on DVD for distribution at nominal cost to Clubs.
I spoke to the ARRL at a ARRL convention to promote such presentations that would be available like some sort of traveling virtual speaker.

Or post it on Youtube - No need for a DVD - someone can just download it and save it.

I would suggest getting some help for this. Someone who is familiar with recording, editing, and synchronizing against the slides can do it in the blink of an eye, but hard to do by yourself.

I like the idea but would suggest a USB drive instead of a DVD, as most laptops no longer have DVD drives and USB/thumb drives are quite inexpensive.


From: Larry Macionski via groups.io<mailto:am_fm_radio@...>
Sent: Wednesday, February 24, 2021 12:07 PM
To: [email protected]<mailto:[email protected]>
Subject: Re: [nanovna-users] Nano VNA: An Antenna Stethoscope ( pdf file latest edition de k3eu )

Barry K3EUI-
I appreciate your dedication to bring this effort to the group.
Obviously there is a Power Point version. You will be in demand when hamfests, return Shortly.
I encourage you to narrate a Power Point Presentation and place it on DVD for distribution at nominal cost to Clubs.
I spoke to the ARRL at a ARRL convention to promote such presentations that would be available like some sort of traveling virtual speaker.

Of course any Idea that takes the ARRL into the 21st century falls on deaf ears. But I would pay easily $20 for a copy that I could use at a club meeting. I am a member of 3 clubs, and trust me, without some sort of presentation such as this would be; those meetings are like watching paint drying. OK now we'll vote on the Treasures Report. All those in Favor?? Why even bring it up, unless the treasury is $0 and - I assure you there would be no Treasurer giving that report of ZERO funds.. Is it any reason, the next generation is not interested in ham clubs and meetings.
W?VFW is now going to alternating monthly meeting with an activity. March will be the 1st meeting since the China plague.

Larry W8LM
ARRL LIFE MEMBER - Licensed 55 years.
VFW post 3115 Amateur Radio Club, W?VFW -Wichita, KANSAS
Past President 2 terms- VE Team Leader 12 years - Training officer.

Barry K3EUI-
I appreciate your dedication to bring this effort to the group.
Obviously there is a Power Point version. You will be in demand when hamfests, return Shortly.
I encourage you to narrate a Power Point Presentation and place it on DVD for distribution at nominal cost to Clubs.
I spoke to the ARRL at a ARRL convention to promote such presentations that would be available like some sort of traveling virtual speaker.

Of course any Idea that takes the ARRL into the 21st century falls on deaf ears. But I would pay easily $20 for a copy that I could use at a club meeting. I am a member of 3 clubs, and trust me, without some sort of presentation such as this would be; those meetings are like watching paint drying. OK now we'll vote on the Treasures Report. All those in Favor?? Why even bring it up, unless the treasury is $0 and - I assure you there would be no Treasurer giving that report of ZERO funds.. Is it any reason, the next generation is not interested in ham clubs and meetings.
W?VFW is now going to alternating monthly meeting with an activity. March will be the 1st meeting since the China plague.

Larry W8LM
ARRL LIFE MEMBER - Licensed 55 years.
VFW post 3115 Amateur Radio Club, W?VFW -Wichita, KANSAS
Past President 2 terms- VE Team Leader 12 years - Training officer.

Hi Dave,

Would love to have a chat to you about your results. I'd like to republish your findings, but wanted to chat about how you came up with them.

Chris
M0VUE

Somewhat off-topic - but at least tangentially related: Just last week I purchased a Comet CA-2X4SR, which is marketed as a dual band 2m/70cm antenna. When I swept it, I discovered it is also resonant on 220, and has less than 1.4:1 across the entire band. Too bad I don't have any radios to take advantage of this!

Sweeps are attached.

Tony W2ASC

This is high quality work. I also had reservations regarding the TDR explanation on the nanoVNA, which was well explained in another post.

I wish there was a bit more commentary to elaborate on the slides so we can hear what you’re thinking when you present them. Perhaps doing up the slide presentation with audio commentary and posting to YouTube? I would very much like to view that.

--
VE6WGM

Barry,
Thanks! Appreciate your hard work. Your explanations parted the clouds for me. Now I feel like I'm flying "VFR on top."
Bob, WA2DLL

On Tue, Feb 23, 2021 at 12:03 PM, Manfred Mornhinweg wrote:

And I hope that this post may help others who have run into the same apparent
dead end.

Thanks for publishing your actions and results!

Please seriously consider writing that up as a sort of "magazine article" and posting it in the group's Files directory. It's a lot easier to find things there than to try to search through a zillion posts in so many threads.

--
Doug, K8RFT

On Wed, Feb 24, 2021 at 04:33 AM, Gyula Molnar wrote:

when the device is connected to the USB port in DFU mode, then the device is not available on the Communication port,

Yes, in DFU mode the NanoVNA is only a memory storage device, not a 'computing' device. No communication, no calculating, no measuring. It is just a "solid state disk drive" thing.

--
Doug, K8RFT

You can also take your Resistive, Reactive, Complex Numbers and run them straight over to Sim Smith for some more fun. I wish we had these Nano's 30 years ago, it's positively amazing what bang for the buck is packed in to the NanoVna. I'm looking forward to design upgrades in the future as far as how it's packaged, would like to see the touch screen done away with for push buttons in a larger model.

Berry -- this is a great bit of work. Lots of meat here and served up very well.

I read this multipule times and get a bit more into my thick skull each time.

Good job!

Don
Km4udx

On Wed, Feb 24, 2021 at 03:28 AM, Barry Feierman wrote:

Nano VNA: An Antenna Stethoscope

I will add my appreciation to Roy's and to his comment about the slightly erroneous TDR explanation.

There are a couple of items i would take up with you-
The picture /display of attenuation versus frequency of the RG-8 is enlightening and you could add a comment that the regularity and smoothness of this graph is a direct indication of the qualities of the cable being sampled. The 'smoother' the better! There are some very nasty variants of Super-8, RG-8, or RG-8Mini type cables with markedly worse characteristics marketed around the world.

I would choose another way of talking about dipole antennas than showing them without a balancing transformer (1:1 balun) at the centre feed point.
As without a balun here one will always have a third element to the antenna i.e. the outside of the coax feeder cable and this extra element will modify all the impedances measured.
As an antenna it still works with both horisontal and vertical radiation components but as a demonstration - I have serious doubts about the results.

Peter

If we have managed to find a solution, please write it down, because we all learn from it. Thanks
--
*** If you are not part of the solution, then you are the problem. ( ) ***