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nanoVNA on Galaxy S5 neo, Android 6.0.1, otg cable, via browser chrome, @
everything works perfectly without other drivers / apps etc
--
*73, Lucio I0LYL Rome, Italy*

As for the Android NanoVNA WebApp (APK off-line version), it now works with
USB-C Android 7.0+ devices that wouldn't work with my other NanoVNA.
NanoVNA-H has the USB-C 1500 ohm resistors installed so I guess if I want
to have my other NanoVNA recognized I'll have to install the resistors manually.

I insert a small USB hub:
so not direct USB-C to USB-C. That hub is not ideal,
because it does not recharge the Android host while it runs NanoVNA WebApp APK

So before purchasing any bad ESN device do a web search and ensure it supports OTG.

FWIW, while Galaxy Nexus nominally supports OTG, the next generation Nexus 4 does not.

I have a VNA that I am working to get sold in kit/assembled form that can
measure 10000+ ohms in the HF in reflection, and can measure 1000+ ohms up
to 600 MHz. I will admit, however, measuring high impedance at VHF/UHF
isnt easy as even tiny amounts of stray capacitance ruin the measurement.
Good fixturing is a must.

In transmission, 10000 ohms is approaching the limit of the S21 measurement
(-50 dB) because of leakage in the SI5351 clock generator. The only way I
know really to fix this would be to use two separate SI5351s to generate
the LO for each port. Not sure if this is worth the effort but certainly
could be done.

It uses the bridge of the EU1KY analyzer which (IHMO) is better designed.
I think the oscillator pins of the SA612s on the NanoVNA are overdriven and
the phase jitter of the IF (which can be considerable when doing a
heterodyne measurement) is not tracked. A Gilbert cell mixer to remain
linear must have its input remain well below 26 mV kT/q (at room
temperature). Also applies common signals to both inputs of the SA612 for
a reason I don't understand, this seems counterproductive.

The design is well shielded and can average over long periods to produce a
relatively high SNR signal from the very low signal input into the SA612.

Hopefully the kit will be available soon....

73,
Dan
KW4TI

For example, if you're transmitting at 3650 kHz and your transmitter has 90W emission at 3650 and 10W at 7300 kHz, your VSWR meter will show you average between 90W at 3650 kHz and 10W at 7300 kHz.

But when you use NanoVNA it will show you VSWR for 3650 kHz with no out-of-band emissions.

if your transmitter has high distortions and out-of-band emission, you will get different VSWR with VSWR meter. Because VSWR meter shows VSWR for all frequencies in the signal. While NanoVNA shows VSWR for specific frequency.

the same, all have 128 kB flash

Hi Herb
My test chamber is just made of parts from the junk box. What you can see is the reverse side of the lid. It has a milled groove along the circumference with same diameter as the inner diameter of the chamber so getting the SMA centerpin on the rod to mate the SMA FF adaptor of the lid is no problem at all. I have a series of test chamber of which I produces the sets so Whitham Reeve and Tom Hagen I the States could measure on the same clamps with same fixture as I did. I attach a zip file with images so you may find inspiration. I also insert a link to the articles we made in thw past.

Kind regards
Kurt

-----Oprindelig meddelelse-----
Fra: [email protected] <[email protected]> P? vegne af hwalker
Sendt: 17. november 2019 01:40
Til: [email protected]
Emne: Re: [nanovna-users] NanoVNA-Saver 0.2.0 #Ferrite_Impedance

Kurt Poulsen wrote:

"Just for the fun of it I measured a blue junkbox core as in my closed chamber as seen on the picture. "

--------------------------------------------------------------------------------------------------------------------

Kurt,
The cylindrical test chamber is impressive. I'm sure the test data it yields is more realistic than the one loop procedure used by the OEM's. Is its construction from a test standard or is it per your own design?

So far I am happy with the numbers I am getting from my fixture. They have been repeatable for identically marked split ferrites.

I was thinking about building something similar to your cylindrical test chamber using a round altoids mint tin or a Tenny Tea tin. Still working on a convenient way to disengage the top cover from the inner conductor to change out solid ferrites.

- Herb

See also W0QE youtube channel - - videos #77, #78, #90 he builds VNA cal sets on all sorts of connectors and compares them with lab-grade cal sets.
--kv5r

With so many vendors selling NanoVNA - does any of them specify the flash size - hence actual processor used ?
Or are they all the same ?

Daniel,
Please reference this document, /g/nanovna-users/files/Miscellaneous/NanoVNA%20design%20notes%20by%20edy555/Make%20your%20own%20calibration%20kit%20CALKIT%20for%20calibration.pdf , from this groups "Files" repository.

- Herb

How are the calibration standards that come with the NanoVNA made? I tried to make some out of SMA cable end connectors and it was a miserable failure. It is extremely hard to crimp/solder anything on to the cable except a RG316. Is there a better part to start with?

The band that the primary problem is 40 meters; my xmtr is running on a
conventional power supply, not battery powered.

Yes, see message #401 from RF And Microwave Mag on this topic.

Alan

On Sat, Nov 16, 2019 at 05:04 PM, Larry Rothman wrote:

Herb,If you know a plumber** and can get a short length of 2 or 3 in Dia
copper pipe, stick some copper end-caps on it and you're good to go after
mounting the hardware. It's not as flimsy as an Altoids container and it's
easy to solder to.?

**Home Despot only has pipe in fixed lengths so a plumber is your best bet.?

---------------------------------------------------------------------------------------------------
Thanks for the suggestion Larry,
The enclosure can be constructed in several ways and to me is the easy part. Disengaging the enclosure top from the inner conductor using readily available coaxial connectors is what I'm trying to wrap head around. I'm thinking of going with some type of friction contact connection like Kurt used. I'm sure my junk pile will turn up something.

- Herb

Oristo,
I ordered a NanoVNA-H which arrived today. In addition to now having a case, it has the battery display diode already installed and also has firmware 0.2.3.2 installed for upgrading without using a jumper to get into the DFU mode.

As for the Android NanoVNA WebApp (APK off-line version), it now works with USB-C Android 7.0+ devices that wouldn't work with my other NanoVNA. NanoVNA-H has the USB-C 1500 ohm resistors installed so I guess if I want to have my other NanoVNA recognized I'll have to install the resistors manually.

NanVNA-H didn't help my Chromebook, it still only recognizes the NanoVNA through the Webapp but not off-line using the APK app.

My wife's ZTE phone has android 7.0 and USB-C but from my research doesn't support OTG, so it doesn't recognize either NanoVNA. So before purchasing any bad ESN device do a web search and ensure it supports OTG. You would think all android 7.0+ smartphones do, but some don't.

- Herb

Has any thought been given to adding some marker math to both the NanoVNA firmware and also to VNA Saver? For example on a log mag plot it would really be handy to display the frequency and the level difference between two markers.

Sam
W3OHM

Herb,If you know a plumber** and can get a short length of 2 or 3 in Dia copper pipe, stick some copper end-caps on it and you're good to go after mounting the hardware. It's not as flimsy as an Altoids container and it's easy to solder to.?

**Home Despot only has pipe in fixed lengths so a plumber is your best bet.?
... Larry

Kurt Poulsen wrote:

"Just for the fun of it I measured a blue junkbox core as in my closed chamber as seen on the picture. "

--------------------------------------------------------------------------------------------------------------------

Kurt,
The cylindrical test chamber is impressive. I'm sure the test data it yields is more realistic than the one loop procedure used by the OEM's. Is its construction from a test standard or is it per your own design?

So far I am happy with the numbers I am getting from my fixture. They have been repeatable for identically marked split ferrites.

I was thinking about building something similar to your cylindrical test chamber using a round altoids mint tin or a Tenny Tea tin. Still working on a convenient way to disengage the top cover from the inner conductor to change out solid ferrites.

- Herb

Hi Andy,

if you are able to do a little Math, you can use an S21 through measurement to measure an impedance.
Only issue: there is in the moment no software available for the nanovna to do the calculation. With the DG8SAQ VNWA the software supports this measurement as well as much other analysis modes. For the nanovna we will have to wait, if somebody implements it into the firmware (e.g. the Smith diagram for S21 could do the math) or software.

Some calculations: with 70dB noise flour and usable 60dB dynamic range of S21 (up to 300MHz) using a divider X to 50Ohm you could roughly calculated measure up to 50kOhm (60dB is a 1/1000 voltage divider, 50K Ohm and 50Ohm roughly give 1:1000)

shows that for high impedance S21 serious through and for low impedance S21 shunt through should be used. In between the S11 reflection method delivers good values.

vy73 de Karsten, DD1KT