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Hello,

yes, I have also performed an OSL calibration in the 150-190 MHz range. The SWR at 172 MHz is 4.5
I made the legs from copper wire with ~1mm diameter. The legs are mounted in a plastic tube. The feed element is a BNC - 4mm connector as shown in the attached picture. The antenna is mounted in vertical position and hangs from the ceiling.

by the way, the antenna works fine at 172 MHz

Did you do an OSL calibration of the NanoVNA over the frequency range of
interest? How is the antenna supported? How is it fed? I cannot imagine an
antenna being that far off. Your length calculations for 172 MHz are
correct. The third harmonic of 172 MHz IS 513 MHz. So the antenna will work
at that frequency. Dipole antennas typically work well at odd harmonics of
the lowest resonant frequency.

What is the SWR at 172 MHz?

Zack W9SZ

On Mon, Mar 31, 2025 at 2:51?AM hobride via groups.io <hobride=
[email protected]> wrote:

Hello everyone,

I have bought a NANO VNA H4 to build simple dipole antennas.

Now I have made a simple dipole antenna for testing. This should be tuned
for 172 MHz. The total length is ~83 cm (2,72 feet), one leg is ~41.5 cm
(1,36 feet).

When I now connect this antenna and try to measure it, the result is a
lowest SWR (1.15) at 513 MHz.

Can this be possible? I am not a radio specialist. I am an IT guy.

I have flashed the NANO VNA H4 to the latest firmware (tried DiSlord and
Hugen) and also calibrated it.

Perhaps I need to make further settings after flashing?

Hello everyone,

I have bought a NANO VNA H4 to build simple dipole antennas.

Now I have made a simple dipole antenna for testing. This should be tuned for 172 MHz. The total length is ~83 cm (2,72 feet), one leg is ~41.5 cm (1,36 feet).

When I now connect this antenna and try to measure it, the result is a lowest SWR (1.15) at 513 MHz.

Can this be possible? I am not a radio specialist. I am an IT guy.

I have flashed the NANO VNA H4 to the latest firmware (tried DiSlord and Hugen) and also calibrated it.

Perhaps I need to make further settings after flashing?

Hi
a Calibrated smith diagram can show you easily the serial resonance frequency and the parallele one ( Xr = 0 Omh ) ,
- use the 401 sweep points option to have maximum frequency accuracy .
- Stimulus band should be selected to be the minimum needed .
- Calibration and measurement prefered after at least 10 minutes for thermal stability .

you can use open coax terminaison or short one , they should give approximatly the same results .

73's Nizar.

Well that makes it simple doesn't it.

Make it slightly longer than expected, then partially cut through the cable or snip it completely off as needed for the short at freq! Cool!

Joe

Joe,
If you short the far end of the coax and connect the NanoVNA to the other end, each half wave will read a short on the VNA. half wavelengths repeat the impedance on the end, quarter wavelengths invert the impedance at the end, i.e. a short will look like an open.
Gary
W9TD

I have a NanaVNA-H4,

And how would I use it to make an exact 1/2 wave or multiple there-of coax?
1/2, 1.0, 1.5, 2.0, etc...
Joe WB9SBD

Have you tried reducing the sweep range? It might be informative to reduce the sweep to 25MHz starting at 300MHz, OSL calibrate at the measurement plane and run the sweep. Then move up 25MHz and run again. This will help focus down on where the issue is. Instinctively, I agree with Manfred, but there may be some oddity creeping in from the nano internals on such a wide sweep.

Steve
G0AIN

You might be receiving strong signals with that antenna, that interfere with the nanoVNA's measurements. If that's the case, at least some of the excursions to negative resistance should not repeat on every scan.

If that's not the problem, it might be just noise.

What am i doing wrong ?

** I think it would have been relevant, since you use nanaovna-saver, to post your .s1p files with your participation.
--
F1AMM
Fran?ois

-----Message d'origine-----

De la part de kellogs

Envoyé : vendredi 28 mars 2025 21:30

Hello,

v0.7.3 on Windows;

Already had my nanovna calibrated in two range: 30 MHz around 315 and another 30 MHz around 434; used an average of 10 sweeps with ~saver which has produced some partly negative values for resistance - measured two (almost) identical antennas, without any in- ~saver calibration. I can say for sure that nanoVNA did not report any negative resistances.

Having seen the failure, i have then set an interval from ~225MHz to 525MHz, some ~300 points, calibrated inside ~saver, remeasured the two antennas with generally different results, but still having ranges of frequency where the resistance was again negative. I have not properly checked what the naonoVNA was reporting on its screen for the frequency range.

What am i doing wrong ?

Thanks!

Use Zeetk (SMC5351A + custom mixer, but this option also work on SM_ST device) or MS5351

In the latest software version: 1.2.43/NanoVNA-H-ZK_20250220.dfu there is an additional generator setting.
Now we have three options in the MODE 1. MS5351 2. ZEETK 3. Si5351.

What to choose with the SMC5351A chip, NanoVNA 3.6.1 SM_ST?

Few people on the LibreVNA list did that, maybe ask there.
IMHO it's not worth it. Sourcing some of the components is a problem and
machining the enclosure is another one.

On Fri, 28 Mar 2025 at 08:55, yura717 via groups.io <yura717=
[email protected]> wrote:

I wonder how much will cost to build LibreVNA / BOM + PCB price /.Thank you

I wonder how much will cost to build LibreVNA / BOM + PCB price /.Thank you

Clyde,
THANK YOU!!! I did not catch the difference earlier, used the H4 firmware and all is working well now!
Thank you.
Bill WB6YVK

If I read your post correctly,
"nanoVNA-H4 hardware build 4.3 using the NanoVNA-H.v1.2.40.bin "
Your problem is you used the WRONG firmware!!!
You can not use "H" firmware on a "H4"!!!!!
And expect it to work correctly.
They are two different NVA's
First, download and install the Firmware for the NanoVNA H4, then try it.
Clyde KC7BJE

Just did a quick search re nanovna-saver and mint and found a set of instructions for you to follow here:



________________________________
From: [email protected] <[email protected]> on behalf of M0CNL via groups.io <m1cxz.m0cnl@...>
Sent: Monday, March 24, 2025 6:50:26 PM
To: [email protected] <[email protected]>
Subject: Re: [nanovna-users] Running NanoVNA Saver (or other software) on Linux

Yes Sudo was what I meant to type but either I fat fingered it on my phone or it was auto corrected to Suso. So sorry about that.

________________________________
From: [email protected] <[email protected]> on behalf of Stephen Thornber via groups.io <stephen.g6sga@...>
Sent: Sunday, March 23, 2025 8:09:50 PM
To: [email protected] <[email protected]>
Subject: Re: [nanovna-users] Running NanoVNA Saver (or other software) on Linux

SUSO ………. sudo perhaps ?

On Sun, 23 Mar 2025 at 20:05, k6whp via groups.io <k6whp=
[email protected]> wrote:

My apologies for being so dense but I cannot seem to unpack the advice
given here. I am running Linux Mint 21.0 something and have been able to
install other packages handily, but cannot get my head around what it takes
to install NanoVNA-saver per the instructions here.

Per your instructions..

<11:44|~> Suso apt-cache search nanovna
Suso: command not found
<11:44|~>sudo apt-cache search nanovna
[sudo] password for whp:
<11:45|~> {{{{nothing occurred after password negotiated}}}}

..howeverr, none of this worked out so, in looking for alternatives, I
found this, and was able to bring saver up.

panda@vika:~$ history
1 sudo apt update
2 sudo apt install python3-pip
3 pip3 install

4 echo 'export PATH=$PATH:/home/panda/.local/bin' >> ~/.bashrc
5 source ~/.bashrc
6 NanoVNASaver


Now my question is how does one connect to the NanoVNA like one would do
searching out the Com port on Windows?


--
William, k6whp
--------------------
"Cheer up, things could get worse. So I cheered up and things got worse."

Yes Sudo was what I meant to type but either I fat fingered it on my phone or it was auto corrected to Suso. So sorry about that.

________________________________
From: [email protected] <[email protected]> on behalf of Stephen Thornber via groups.io <stephen.g6sga@...>
Sent: Sunday, March 23, 2025 8:09:50 PM
To: [email protected] <[email protected]>
Subject: Re: [nanovna-users] Running NanoVNA Saver (or other software) on Linux

SUSO ………. sudo perhaps ?

On Sun, 23 Mar 2025 at 20:05, k6whp via groups.io <k6whp=
[email protected]> wrote:

My apologies for being so dense but I cannot seem to unpack the advice
given here. I am running Linux Mint 21.0 something and have been able to
install other packages handily, but cannot get my head around what it takes
to install NanoVNA-saver per the instructions here.

Per your instructions..

<11:44|~> Suso apt-cache search nanovna
Suso: command not found
<11:44|~>sudo apt-cache search nanovna
[sudo] password for whp:
<11:45|~> {{{{nothing occurred after password negotiated}}}}

..howeverr, none of this worked out so, in looking for alternatives, I
found this, and was able to bring saver up.

panda@vika:~$ history
1 sudo apt update
2 sudo apt install python3-pip
3 pip3 install

4 echo 'export PATH=$PATH:/home/panda/.local/bin' >> ~/.bashrc
5 source ~/.bashrc
6 NanoVNASaver


Now my question is how does one connect to the NanoVNA like one would do
searching out the Com port on Windows?


--
William, k6whp
--------------------
"Cheer up, things could get worse. So I cheered up and things got worse."

I am locking this topic as it has gone far afield of discussion related to NanoVNAs.