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Just wondering about how to increase the highest value of impedance
measurements. Since it tops out at about 600 ohms in HF
I was thinking along the lines of resistive shunt and back calculating.

Without fully working thru the math, I >>guess<< that back-calculating shunt
would lack better accuracy (S/N) than straight measurement.

I wonder how others tackle the problem?

A green (not blue) ~US$10 reflection bridge
e.g. from eBay
with matched SMA references (want a matched pair to calibrate nanoVNA CH1)

Thanks for the reminder and suggestions. Yes, I have calibrated using my
cables to connect with my antenna. This users group is great!

Dick,
I forgot to add that currently all firmware releases for the NanoVNA-F are single sourced by BH5HNU. One of the advantages of the smaller NanoVNA is it has a number of creative firmware developers who continually push the limits of its measurement capabilities. Features that these developers have added to the NanoVNA, such as TDR measurement, extending the frequency range to 10 kHz and 1 Hz frequency resolution, will mostly likely only be added to the NanoVNA-F through direct request to BH5HNU.

- Herb

Dick,
The Nano-F has different firmware that is not compatible with the smaller NanoVNA. You can still perform TDR measurements from the PC side using NanoVNA-Saver or NanoVNA-Sharp. You can also make a request to BH5HNU on the NanoVNA-F group forum ( /g/nanovna-f) to add TDR to a future firmware release.

- Herb

Accidental issues are not the end of the world - just turn it in again.

I have a NanoVNA-F (Firmware Ver. 0.0.3). I also have
a Users Guide that talks about the TDR function.

I cannot find that function on this NanoVNA. Was the
TDR function a Firmware Update ?

Thanks for the help on this.

Dick, W1KSZ

An electronic switch that has to be pressed for a second or two to turn the device on or off would be even better in order to prevent accidental issues.?



On Sat, 16 Nov 2019 at 10:13 AM, Harold Farrenkopf via Groups.Io<hfarrenkopf@...> wrote: I knew they were crappy switches and replaced mine with a good quality toggle switch while I installed it in the printed case i bought. I replaced the jog switch as well and mounted a small slide switch where the jog switch was to use for the firmware writing (recessed so it needs a small rod/tool to move it)

Please be aware you may be able to calibrate till 1500MHz but the measurement of anything different from SOL can still be completely wrong due to non linearity errors

--
NanoVNA Wiki: /g/nanovna-users/wiki/home
NanoVNA Files: /g/nanovna-users/files
Erik, PD0EK

Ron,

Have you calibrated he nano with a calibration standard of the same style that your antenna connector is? I.E if your cable connected to the radio has a male UHF connector, your nano needs to be calibrated with a male uhf set. If you calibrating with the SMA set and then attaching an adaptor or adaptor cable to connect to the antenna cable the readings will be off. A VNA no matter if it cost $50 or $100k always needs to be calibrated at the plane of measurement. Here, the plane of measurement is the point you attaching your antenna cable. Since the VNA looks not only at forward and reflected power but also at phase not calibrating it right will cause errors in either direction...i.e. either read too good or too bad. You can make male calibration sets yourself that are adequate and only have minute errors vs commercial sets. U-tube has quite a few instruction videos how to do it.

John,
Try Dennis Real's firmware release for an even better antenna analyser experience. Search for forum member reald here or on GitHub.?



On Sat, 16 Nov 2019 at 11:00 AM, John Ackermann N8UR<jra@...> wrote: Thanks!? That seems like a really useful combination then -- simple,
easy to read display on the go, with full power when you're connected to
a host.

Thanks! That seems like a really useful combination then -- simple,
easy to read display on the go, with full power when you're connected to
a host.

On Sat, Nov 16, 2019 at 11:45 PM, John Ackermann N8UR wrote:

Will this firmware version provide full functionality when used with an
external program like NanoVNA-Saver?

Thanks,
John
----

On 11/16/19 10:11 AM, rolf.ch.bucher@... wrote:

Excellent alternative. It helps dramatically to read the display.
Rolf

Yes, full functionality is available.

hugen

Will this firmware version provide full functionality when used with an
external program like NanoVNA-Saver?

Thanks,
John
----

On Sat, Nov 16, 2019 at 11:23 AM, hwalker wrote:

On Wed, Nov 13, 2019 at 07:16 AM, Larry Rothman wrote:

"There is an interesting discussion on hugen79's NanoVNA Issues page on

Github

regarding circuit changes/mods to reduce overall noise levels."

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

Larry,
Hugen posted a chart a few hours ago showing the results of a new PCB with
some of the recent improvements installed (see attachment). S11 looks to be
<= 40 dB to 1500 MHz and S21 dynamic range is >= 50 dB to 1500 MHz.

- Herb

This image shows uncalibrated data and is used only to show that the resistance bridge on the optimized pcb still works well up to 1.3G. But because the 5th harmonic will be small, the sa612a itself produces harmonics, and the calibrated effective dynamic is still only 20dB.

I knew they were crappy switches and replaced mine with a good quality toggle switch while I installed it in the printed case i bought. I replaced the jog switch as well and mounted a small slide switch where the jog switch was to use for the firmware writing (recessed so it needs a small rod/tool to move it)

Excellent alternative. It helps dramatically to read the display.
Rolf

On Sat, Nov 16, 2019 at 10:31 PM, Larry Rothman wrote:

You are correct for scanraw and color...not needed for pc.?
Capture used for screendump.?
Dump used to dump Cal and measured parameters.?
Please look at my Console Commands doc in files section.?
On Sat, 16 Nov 2019 at 8:32 am, Karsten, DD1KT<ktholmann@...> wrote:
Hi all,

sorry to ask , but I need a translator help for "DUMP, SCANRAW, COLOR commands
are not available".

Please correct me, if I got it wrong:
Dump? is "screen dump", so a copy of the screen by a PC software.
SCANRAW : reading of scan values without correction applied: Do I need this
for a Software linke NanoVNA-Saver or is it an unused feature?
COLOR: sounds like a manual setting of the colors ? Is it used by PC software
and which?

@Cornellu:
Others may again correct me, but aa-Version is the name for
"Antenna-Analyser", which means, that that only S11 (CH0) and 2 traces on the
device are supported, but with bigger Fonts. No S22 "through" measurements
possible.

vy73 de Karsten, DD1KT

The aa version can still be used for s21 measurements, and just to display larger fonts, trace 2 and 3 are removed, and you can still display s21 data in trace 0 and 1.

hugen

Just wondering about how to increase the highest value of impedance measurements.

Since it tops out at about 600 ohms in HF how would I measure a half wave endfed of similar ?

I was thinking along the lines of resistive shunt and back calculating.

I wonder how others tackle the problem ?

73 de Andy

You are correct for scanraw and color...not needed for pc.?
Capture used for screendump.?
Dump used to dump Cal and measured parameters.?
Please look at my Console Commands doc in files section.?
On Sat, 16 Nov 2019 at 8:32 am, Karsten, DD1KT<ktholmann@...> wrote: Hi all,

sorry to ask , but I need a translator help for "DUMP, SCANRAW, COLOR commands are not available".

Please correct me, if I got it wrong:
Dump? is "screen dump", so a copy of the screen by a PC software.
SCANRAW : reading of scan values without correction applied: Do I need this for a Software linke NanoVNA-Saver or is it an unused feature?
COLOR: sounds like a manual setting of the colors ? Is it used by PC software and which?

@Cornellu:
Others may again correct me, but aa-Version is the name for "Antenna-Analyser", which means, that that only S11 (CH0) and 2 traces on the device are supported, but with bigger Fonts. No S22 "through" measurements possible.

vy73 de Karsten, DD1KT

D.M.Kerns and R.W.Beatty : "An understanding of this introductory microwave
network analysis is essential to the serious worker in the ?eld of microwave
measurements. In order to investigate errors in measurements, one must have
in mind precisely what quantity is desired in the measurement. Basic definitions
of these quantities involve both explicit and implicit assumptions which must be
recognized. In addition a knowledge of these analytical tools should be helpful
in understanding error analyses already performed by others and described in
the literature.", Basic Theory of Wave guide Junctions and Introductory
Microwave Network Analysis, Part 2, Introductory Microwave Network Analysis,
2.0.Introduction to Part 2, p.34, Paragraph 3, International Series of Monographs
in Electromagnetic Waves, Editors: A. L. Cullen, V. A. Fock J. R. Wait, Volume
13, Pergamon Press Inc, First Edition, 1967.