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I have to agree - I have been pulling out my hair trying to tune a 70cm QFH (Dual 1/2 turn helix) antenna.

The results I get is very sensitive to length, so much so that I gave up in the end. I have tried to re-calibrate further down the feed line, but it just move the results around.

Hello all, just a quick introduction from myself. Recently purchased nanovna H.
Looking forward to getting to grips with it potential.
Thanks to all those who have shared their technical knowledge, I am finding great info for a total beginner.
73s for now
Ernie. GM0EZP

v0.1.4 2020-03-26 : This update requires recalibration of the device
1) Supports 0dBm output (fundamental frequency, for HW V3.1 & HW V2.3 only, for HW V2.2 still -13dBm output);
2) No new features were added compared to firmware v0.1.1.
How to know my NanoVNA-F HW version?: /g/nanovna-f/wiki/How-to-know-my-NanoVNA-F-HW-version
v0.1.0&v0.1.1 2020-02-03 : This update requires recalibration of the device
1) Add TDR feature;
2) Add marker tracking feature & dynamic update of frequency and other information when the mark moves;
3) Add ordinate display
4) Support to 10kHz frequency
5) Some font, color, and layout optimizations
6) Suggestions from groups.io/nanovna-f & facebook group members and much more, thank you for your feedback
(1) a beep to the end of each standard measurement in calibration
(2) callsign.txt expanded to 44 chars, not limited to call sign display, can display your phone and email address, etc.
7) The startup information is not displayed for a long time at present, you can call it up in the menu. Just into the menu: CONFIG -> ABOUT
v0.0.5 2019-12-30 : This update requires recalibration of the device
1) Support measurable frequency to 1.5 GHz, default setting 1 GHz, accurate measurement up to 1.35GHz;
2) Fix: unexpected 0.3dB offset of s21 in thru;
3) Fix: mark all off bug;
4) Fix: clutter display when standing wave ratio is infinite;
5) Add version & info command;
6) Add REAL IMAG R X trace format.
v0.0.4 2019-10-30 : This update does not require recalibration of the device
1) Can display call sign;
2) fix BUG: CW=100MHz do not output
3) Optimize Chinese translation
4) How to display your call sign: /g/nanovna-f/wiki/How-to-add-call-sign-display
v0.0.3 2019-10-07 : This update requires recalibration of the device
1) support NanoVNA's PC software;
2) Add a boot tone;
3) Optimize band (<100MHz) S11 measurement results
v0.0.2 2019-08-29 : First Release

Github:
Groups.io: /g/nanovna-f
Files: /g/nanovna-f/files
Wiki: /g/nanovna-f/wiki
Facebook:
Website: deepelec.com
Thank you for your support to BH5HNU and deepelec :-)

On Fri, 24 Apr 2020 at 15:51, <whdpc113@...> wrote:

If you have a bad mismatch, the reactive part of the impedance will vary

along the length of the feed line. What your rig sees at the end of the
feedline, and what the MFJ sees with a jumper and your rig behind it may
differ. Does the SWR reading on the rig change with and without the MFJ
inline? I have found VHF and UHF antenna SWR very sensitive to small
changes in length/tuning.

With a VSWR > 1, *both* the real and imaginary (reactive) part of the
impedance vary as one moves along a transmission line. It is not just the
imaginary component as you say. If that transmission lines was lossless,
the VSWR would remain a *constant*, not vary as you say. The impedance
varies along the transmission line, but the VSWR remains constant.

What any piece of test equipment shows depends on its quality.

Dave, G8WRB.
--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United
Kingdom

On Sun, Apr 26, 2020 at 11:09 PM, Alex wrote:

Developers can release binary files without publishing the source code, is
that okay?

Not if any portion of the code is open source. If the code was entirely rewritten from scratch (doesn't seem likely), then it's OK.

Hello,
NanoVNA-F has it's own groups.io and after-sale support~
You can visit groups wiki to get what you want: /g/nanovna-f/wiki/How-do-I-upgrade-the-firmware

Yes, I agree. Because it is an OSS project, we have not restricted BH5HNU to continue to sell NanoVNA-F.
But do you think NanoVNA-F is still an OSS project? Developers can release binary files without publishing the source code, is that okay?

All,

Where can I find the instructions on upgrading to the latest firmware version for the -F model and what is the latest version? Thanks in advance...

Larry, K4MLA

Doug, I will try that tomorrow.... that’s one thing I didn’t check

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)*
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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