开云体育

There is a tutorial which I have referred to in the past for such a purpose
on the Fair-Rite www site.



Look under "Technical Resources" at the bottom of this folder. You will
find an excellent presentation there on how to determine what you have in
terms of ferrite cores. You can use the NANOVNA at the bottom end of its
frequency coverage to measure the inductance which you will need. What is
required:
1) The dimensions of the core / toroid
2) The measured inductance with a known number of turns (it will guide you
in this respect).
3) The number of turns on the toroid
4) The frequency of measurement (don't remember if this is necessary)

Then there is an applet you input these values into which comes up with the
material. It's golden.

Dave - W?LEV

--
Dave - W?LEV

We can analyze the characteristics of the ferrites in the drawers with a nanoVNA device and a nanoVNA-Saver program.
These "curves" should then be compared with the curves given by the manufacturers.

You can see such curves, e.g. here:

The first ferrite measurements with the nanoVNA were discussed by forum members here: /g/nanovna-users/message/6996 and in subsequent discussions. (/g/nanovna-users/topic/nanovna_saver_0_2_0/54247421?p=Created,,,20,1,20,0&jump=1)
NanoVNA Sorts Unknown Ferrite Suppression Beads

So whoever is interested in the topic can do it. nanoVNA-Saver -> Display setup -> S11 with R/ω & X/ω (?Ω/Hz) selection.

--
Gyula HA3HZ ( )

Good afternoon. I am not sure but I don't think I have seen this mentioned as yet another tool for the NanoVNA. Can the Nano be used to help identify anything about any of the cores that are sold by Amadon or Fairite? I have many unidentified cores and would like to try to identify them as well as many others out there.

Thanks
Fred - n4cla

Sent from Mail for Windows

From: Roger Need via groups.io
Sent: Thursday, June 30, 2022 12:14 PM
To: [email protected]
Subject: Re: [nanovna-users] Where to buy Genuine Nanovna

On Thu, Jun 30, 2022 at 07:57 AM, <wayne@...> wrote:

Hi all, it’s been a while since I followed this group but perhaps somebody
can suggest the best place to buy a genuine Hugen NANOVNA. H4
Any help greatly appreciated

It appears you are in Australia and I have not heard of any dealers there that sell genuine Hugen H4 units. I would suggest you order directly from Hugen's Zeenko store in China. Yo can get courier delivery if you are in a hurry. Buy an SD card from them as well since some products do not work with the H4. If you want to use PayPal send them a message and they can accommodate you...



Roger

Well my original goal was to determine if it was safe to use both antennas at the same time (one TX- one RX) on two different radios. I can see that would not be wise. Thanks for all the help. Can't learn anything without asking dumb questions!

r and l electronice

On Thu, Jun 30, 2022 at 07:57 AM, <wayne@...> wrote:

Hi all, it’s been a while since I followed this group but perhaps somebody
can suggest the best place to buy a genuine Hugen NANOVNA. H4
Any help greatly appreciated

It appears you are in Australia and I have not heard of any dealers there that sell genuine Hugen H4 units. I would suggest you order directly from Hugen's Zeenko store in China. Yo can get courier delivery if you are in a hurry. Buy an SD card from them as well since some products do not work with the H4. If you want to use PayPal send them a message and they can accommodate you...



Roger

What do the creators recommend?
Well, they list all that on their web sites.
First link is NanoVNA, 2nd link is NanoVNA V2

--
Tate Belden

*NOTE: ka7o@... <ka7o@...> has been depreciated, please
use this address instead: wyoham@... <wyoham@...>*

"The Dungeon <>"

"We do not become enlightened by imagining figures of light, but by making
the darkness conscious."

The Nanovna website has some suggestions. Look for "Buy a NanoVNA" in the contents list.

Much more than +64 dBm and you are very close to digital saturation on the
A/D. Personally, I wouldn't go there without at least a 20 dB attenuator
inline. Of course, that will also decrease your general received signals
by 20 dB.

Dave - W?LEV

--
Dave - W?LEV

Hi all, it’s been a while since I followed this group but perhaps somebody can suggest the best place to buy a genuine Hugen NANOVNA. H4
Any help greatly appreciated

Thanks

Wayne. VK6EH

Hi Marv,

The previous reply showed you that the signal level in the second antenna would be -9 dBm.

Normal signal level calibration for a receiver is a S9 signal is 50 microvolts at the antenna, in dBm this is -73 dBm.

Your signal level of -9 dBm is 64 dB above that. That would read S9+64dB on you S meter.

Some S meters read S9+40 some S9+60. This would be full scale on you S meter and more.

This may be close to the receiver overload point.

If your receiver has built in attenuator, I would select 20dB or 40 dB or more to get the signal to where the receiver can comfortably handle it.

Hope this helps

73 Greg WA1JXR

Hello Marv,

I can tell by reading your question that some of your understanding of how the Nano VNA works is not clear.

First the Nano VNA has two connectors they are referred to as Channel0 and Channel1

The Nano VNA has two operation modes, Refection and Thru

Cannel0 is used for reflection mode measurements

Channel0 and channel1 are used for thru mode measurements

Think of the two antennas as a two-port network. Measuring the insertion loss (S21) between the two antennas will give you the coupling from one to the other.

You only need the display set up for LogMag

There is no crossing of one trace to the other. The LogMag trace gives you the coupling between the antennas as a function of frequency.

I assume you are doing the correct frequency start stop set up and a full SOLT calibration

The previous reply showed you how to calculate the amount of power induced into the second antenna when 25 watts is present on the first one

Hope this helps clear up things for you.

73 Greg WA1JXR

Thanks - that's exactly what I was looking for. Now I need to figure out how something like 1/10th milliwatt coming in on my ICOM IC-7300 receiver's front-end relates to its specs. Its sensitivity is about 1/10 microVolt.

That would be 25 Watts minus 53 dB.
25 watts is 44 dBm
44 - 53 = -9 dBm? ?Or about? 1/10th milliwatt
Now you know why they like to keep the loops REAL close for inductive charging.
Kent WA5VJB

I am trying to use my NanoVNA-H to see how much near-field coupling I have between two antennas in my backyard that are about 10 feet apart. I have one antenna connected to the S11 port and the other to the S21 port. I have S11 set to SWR and S21 set to LOGMAG. LOGMAG is -53dB at the point in the graph that both lines cross. I assume that is the amount of power being induced in the antenna connected to S21 by the antenna connected to S11.

Since the NanoVNA is only putting out a small amount of RF power, how would I relate that to for example transmitting 25 watts on one of these antennas and determining how much power is being induced in the other antenna?

In one of these threads someone mentioned the special SD formatting app that you can download for free, and in cases where you get strange behaviour you can always try that.

An SD card appears as at least one "drive" in many operating systems, but this is sort of a convenience rather than reflecting an actual mountable file system on the device itself. If you ever wondered why the advice for cameras and so on was to format the card on the device instead of using the OS tools, this is why. The SD format can be made to appear as a mounted file system on a modern OS, but it is actually a much different beast, physically. And some devices will refuse to recognize an SD card that has not been SD formatted because the SD format is quite specific to the hardware and software on the card.

Some devices just can't figure this out if the card has only been formatted using typical OS tools -- mostly because those tools do not actually do an SD level format. Most modern devices are more forgiving, but embedded devices (like cameras) have long had a problem accessing anything on the card unless it was formatted by the engine on the embedded device, which is a kind of format not at all like the one on the OS.

This is probably why factory fresh cards may work, but any older ones floating around in a box that has previously been written to by Windows may not always work in all devices.

We had an in-depth discussion on this subject a few months ago in this group....
/g/nanovna-users/topic/90696010#27854

Roger

I had a write fail using a 16MB SanDisk, "properly formatted." Right.

A few days ago I received and tried the 16MB Patriot. It saved instantly, and without having to format it.

NanoVNA-H