开云体育

Here is a second report on the effect of calibrating the NanoVNA on SWR and Return Loss measurements. This time a 20M dipole was used as the antenna. It was surprising to me to see how good the measurements were when using the default 50 kHz. to 900 MHz. calibration and setting the Stimulus range to 13 to 15 MHz. Interpolation works well under certain conditions.

Roger

On Sat, 25 Apr 2020 at 17:52, Alex <kimalakia@...> wrote:

I am a partner of SYSJOINT, and I must clarify that BH5HNU used to be an
employee of SYSJOINT. He was responsible for NanoVNA-F project, and -F was
originally sold through SYSJOINT's Aliexpress shop(hamelec.aliexpress.com),
but when -F became popular and produced some benefits, BH5HNU betrayed
SYSJOINT under the drive of interests. He left SYSJOINT and continued to
produce and sell -F in the name of deepelec, we still have some legal
disputes with BU5HNU and his new company.

Unless he signed a non compete contract while he was employed by you there
is nothing that you can do.
OSS project, anyone can sell their own copy/version.

I did some measurements today on a vertical whip antenna tuned for the top end of the 2M amateur band. I wanted to see the effect of calibrating the NanoVNA on SWR and Return Loss measurements? The conventional wisdom is that the closer you calibrate to the frequency range of interest the more accurate the results. How close is close enough? That depends on how important accuracy is to you in your measurements. The first measurement was done using the factory default 50 to 900 MHz. calibration. The second was done by changing the Stimulus range (zooming) of the NanoVNA to 140 to 155 MHz. while still using the factory calibration. I then re-calibrated from 140 to 155 MHz. and repeated the measurement. Subsequent tests did zooming and calibrating to an even narrower range. You can clearly see the effect of calibration on the results...

Roger

BU5HNU has always claimed that he is the original designer of -F, which
literally seems to be true, but the truth is that an employee leaves the
company and starts to manufacture and sell the same products as the former
owner. What do you think of this behavior？

I'd say "Welcome to the world of open source. That's how it's supposed to work."

The whole point of open source is that if someone thinks they can do better, they should have the chance to try. That keeps every supplier on their toes, to the benefit of the customers.

Clifford Heath VK2CLF

macOS Catalina
Version 10.15.4

Rebooted to Recovery Mode
Disabled SIP (csrutil disable)
Restarted in "regular" mode
device shows up as /dev/cu.usbmodem4001

Used NANOVnA to scope out antenna

Rebooted to Recovery Mode
Enabled SIP (csrutil ebable)
Restarted in "regular" mode
device still shows up as /dev/cu.usbmodem4001

Moral of the story is it worked even after re-enabling SIP. Now I have to get it to work using vmWare Fusion and Windows 7. Hope this is helpful...

73 Mark KG0RMS

On Sun, Apr 26, 2020 at 01:46 PM, <reuterr@...> wrote:

Hello DiSlord,
Will you please so kind and provide your firmware version 0.8.4.4 also for the nanoVNA-H (not H4).
===============================================
Rudi,
Please be aware that the H4 has more flash memory space and a faster processor than the -H. Some features that were introduced for the H4 by DiSlord such as 201 pts and 7 configuration slots can not fit in the -H limited flash memory space.

That was one of the prime motivations for me upgrading to the H-4 besides it 4 " display. The H4 is more future proof and I foresee more innovative features for it in the future. DiSlord is already considering implementing support for the optional sandisk capability of the -H4 for saving screen shots and trace data.

- Herb

On Sun, Apr 26, 2020 at 07:28 AM, CT2FZI wrote:

Also, for L/C circuit where can I find a 1% accurate capacitor around 50 or 100 pf?

I have several CDE silver mica capacitors I ordered from Mouser, and have several more on back order. I bought leadless surface mount capacitors, but they also have leaded varieties. The ones I bought are 1 percent tolerance, but some are also available in 0.5 percent tolerance, or even 0.1 pf tolerance. That's probably overkill (also expensive). The 1 percent caps I bought were just under 5 dollars each, if I remember correctly. If you can live with 5 percent tolerance, the price is probably half that, but I figured 5 bucks for a Hi-Q, tight tolerance capacitor I can use for a "standard" is cheap.

Hello DiSlord,
Will you please so kind and provide your firmware version 0.8.4.4 also for the nanoVNA-H (not H4).
73, Rudi DL5FA

On Sun, Apr 26, 2020 at 10:44 AM, Dick wrote:

There must be something else as I cannot reproduce your results.
...... Trying to measure a 10 mH RF Choke, display bounces around from 190pH to 600pH. ..
==============================
Dick,
Sorry for the delayed response. I work at rf frequencies that only requires micro-henries for suppression and steering and haven't testing any chokes in the milli-henry range. It took me a while to hunt down something in my parts bin.

I found an old J. Miller 16mH choke which was too large to fit in the sma-banana plug, so I had to use micro-clips (see attachment). I don't know what test frequency manufacturers specify their chokes at but the J. Miller choke quickly became capacitive with high impedance above 200 kHz. I limited my sweep to 30 kHz-200kHz for testing. In that range values between 16.9 - 22.9 mH were measured. At 50 kHz the impedance of the choke measured closest to the NanoVNA system impedance (50 ohms) and the coil value was 16.7 mH (see screen shot attachment). If I was sorting components I would have used that value.

I also found a J. Miller 60mH choke but it wouldn't measure correctly and close examination with a magnifying glass showed that one of the wires had broken off its terminal. Tagged and marked for repair.

- Herb

Hi Herb,

Good thing those banana adapters are OK for DC, I will opt for that method.

I will need to measure some coils for end fed antennas and a coil in a
trap, lets see what I can do. At 1MHz I think I will be very happy with 5%
or less! :)




*73 de Luís, CT2FZI*

*QRV @ 145.300 MHz | **CQ0VMST (VHF REP Monsanto)*
<>



<>

Hi DiSlord,

Flashed your latest firmware 0.8.4.4, no problems sofar. Please find attached my results measuring the 50 Ohms standard , 50 Ohms standard paralleled by 50 Ohms and CH1, after calibration.

After flashing, the threshold setting still was 300900000, my setting before the? flashing.

Best regards

Jos

There must be something else as I cannot reproduce your results.
Now, I am using a NanoVNA-F, but I can't see where that matters.
Trying to measure a 10 mH RF Choke, display bounces around from
190pH to 600pH.

Guess it's back to my LCR Meter, at least I can get that to work.

Tnx for the reply,

73, Dick, W1KSZ
________________________________
From: [email protected] <[email protected]> on behalf of hwalker <herbwalker2476@...>
Sent: Sunday, April 26, 2020 10:34 AM
To: [email protected] <[email protected]>
Subject: Re: [nanovna-users] [Measuring] What is your favourite method of measuring inductance in a coil?

Dick 9:58am #12913
What settings did you use to get these measurements ?
=====================================
Dick,
No special settings. Just turned off the CH1 traces, set the frequency sweep from 50k - 1M, and read the inductance on CH0 from the smith chart readout as shown in the screenshot.

- Herb

Dick 9:58am #12913
What settings did you use to get these measurements ?
=====================================
Dick,
No special settings. Just turned off the CH1 traces, set the frequency sweep from 50k - 1M, and read the inductance on CH0 from the smith chart readout as shown in the screenshot.

- Herb

What settings did you use to get these measurements ?

Tnx, Dick, W1KSZ
________________________________
From: [email protected] <[email protected]> on behalf of hwalker <herbwalker2476@...>
Sent: Sunday, April 26, 2020 8:33 AM
To: [email protected] <[email protected]>
Subject: Re: [nanovna-users] [Measuring] What is your favourite method of measuring inductance in a coil?

Luis,
Most commercial LCR meters for less than $200 only measure inductance or capacitance below 1 MHz. Manufacturers specify the values of their inductors or capacitors at a specific test frequency, also usually below 1 MHz. The NanoVNA can give measurements to at least 5% for inductors and capacitors using fairly simple fixtures such as the sma-banana plug adapter in the attached photos.

The attachments shows a Cambion 22 uH inductor being measured. From 50 kHz - 1 MHz the measured values vary from 22 uH by 0.5 uH.

If you attempt to measure the inductance or capacitance of the components at higher frequencies then the lead length, self-resonant frequency, and fixture all start to come into play with your measurements.

- Herb

Luis,
Most commercial LCR meters for less than $200 only measure inductance or capacitance below 1 MHz. Manufacturers specify the values of their inductors or capacitors at a specific test frequency, also usually below 1 MHz. The NanoVNA can give measurements to at least 5% for inductors and capacitors using fairly simple fixtures such as the sma-banana plug adapter in the attached photos.

The attachments shows a Cambion 22 uH inductor being measured. From 50 kHz - 1 MHz the measured values vary from 22 uH by 0.5 uH.

If you attempt to measure the inductance or capacitance of the components at higher frequencies then the lead length, self-resonant frequency, and fixture all start to come into play with your measurements.

- Herb

I use XJW01 digital bridge 0.3% for measure R, L, C

Measure C: 0,1 pF–10000 mF
Measure L: 0,01 uH–1000 H
Measure R: 0,0002 Ом–9,999 МОм

If calibrate on good calibration standarts allow get better result

Use for measure 4 wire line

It show very good result

Hello team,

Trying to understand a good method of measuring the inductance - lets say around 110uH - of a coil.

Is the L/C method the best? Is there any direct method of measuring the L?

Also, for L/C circuit where can I find a 1% accurate capacitor around 50 or 100 pf? If this LC method is the best, then I will make a jig where the capacitor its already embedded and I only add the coil.

Cheers!


Luis CT2FZI

You don't need to add a switch, just use the same jumper as I used which is the method the H4 uses and you only need to hold down the jog switch when turning on the Nano.?
/g/nanovna-users/message/10026





On Sun, 26 Apr 2020 at 5:01 AM, Aleksander Shalygin<shalygin@...> wrote: Did so. It has become convenient to enter programming mode.

Hugen! Go ahead!
Design on max2870, adf 4355

Did so. It has become convenient to enter programming mode.