开云体育

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. ( ) ***

Hello everybody,

Because the product can be connected to multiple versions and multiple operating systems, it’s pretty hard for everyone to “chew by mouth” what to do.
I’m not even talking about people being at different levels of electronics knowledge.
Therefore, in many cases, the description is either too detailed or provides too little information.
When someone asks a question, they either know the answer (it mostly turns out the way they ask) or don’t really understand what they need to do.
In the latter case, he is still in an enhanced nerve condition. It is nervous that this is happening with His structure.
So there are many of us and we react to a given question or answer in many different ways.

The forum will help us try to solve the problem.
As the firmware and PC software development of the products is likely to push its limits, there is probably not much development i.e. change not expected.
We know the time course of product development. For those who don’t know, it’s worth reading my website.
From the first release, I try to gather the information and if I find that someone else needs to know it, I will publish it.

Now, for example, a firmware upgrade has occurred.
In DFU (Device Firmware Upgrade) mode, the device cannot be accessed through a COM port.
After all, the firmware required for the operation of the device is uploaded (or downloaded).
In DFU mode, the device driver must be searched among the USB contollers as the STM Bootloader driver when the device is connected to the USB port in DFU mode.
I repeat, then the device is not available on the Communication port, it makes sense.
Earlier operating systems required more manual installations, there were no automatic driver installations.
We learn all this together. You can just build on the basics, do you.

73, Gyula HA3HZ
--
*** If you are not part of the solution, then you are the problem. ( ) ***

Hi everyone

Thank You Don, for msg #20899
A little addition for those who run into this problem under Windows XP.
The STM Bootloader driver is not automatically installed on this operating system when installing the DfuSe demo, so you must do so as above (exclamation point in yellow triangle for USB contorollers in Device Manager) after placing NanoVNA in DFU mode and PC USB connection in Device Manager.
So look for the error message, click on it, and after unpacking, mark the STM Bootloader Driver package so that the system can install it.
If you have already installed something, delete it and install it. This package also solves the problem on XP.
Link:
If you still get stuck, visit my website as well.

73, Gyula HA3HZ
--
*** If you are not part of the solution, then you are the problem. ( ) ***

Barry-

Very nice presentation on the basics of VNA analysis. Quite well done. I’m sure you put in considerable time on it.

After doing a quick review of your slides there were only a couple items that I felt needed correction.

They both relate to your discussion of TDR measurements using a VNA. In slides # 9 and 19 you speak about pulses of RF being sent out. That would be correct for a conventional TDR, however the TDR plots generated by a VNA are created by applying a FFT to the steady state (not pulsed) reflected signal of the VNA. No electrical pulses are involved. The TDR function is based on the mathematical FFT.

The remainder of the slide set looked pretty good based on my quick reading.

Best Regards,

Ray
WB6TPU

Here is my latest rendition of the pdf file: Nano VNA: An Antenna Stethoscope
After giving a few Zoom club talks on the Nano VNA, I've changed my approach a bit.
This is still a very basic look at how a VNA can be used as a "tool" in your antenna toolbox.
I hope it explains why impedance changes with feed line length and approaches resonance in a novel way.

Feedback is appreciated, both on and off this IO group.

de K3eui
Barry
West Chester PA
k3euibarry@...

Good Afternoon,

Did you reset and calibrate per band you were sweeping? In my
experience, getting those kinds of results usually means either the antenna
is not resonant on those bands or there is something wrong with the
calibration. I usually calibrate each band separately and save them out.
Set the sweep start and stop points. Go to the calibration menu, hit
reset, then perform a calibration.



Jim Barber
KJ7JGB
Phone: 503.547.9524
<>

Properly used it only links to other subjects with the same hashtag - it's superfluous in a group like this and should be constrained to twitter where the trendy junk originated from..

Don:

You were spot-on. I opened Windows Device Manager, manually updated the driver to the DFU-capable driver. NanoVNA H is now running version 1.x build from Jan 2021.

72,

Marc, W6MGV

Ref Dave W0LEV antenna drawing

I don't see any dimensions for the horizontal elements? Can you add them to drawing?

Thanks

On Mon, Feb 22, 2021 at 11:58 AM, Chris wrote:

I’m having exactly the same problem

Well then, you should try the same solution.