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In answering the 'accuracy' question, error bars must be considered.
Evidently error analysis and calculus of variations is no longer taught in
the schools. They both were part of the advanced physics labs I took some
50 years ago.

Dave - W?LEV

--
*Dave - W?LEV*
*Just Let Darwin Work*

Ken,

you may find /g/nanovna-users/files/Nano%20VNA%20Saver/nanoVNA-H4%20software%20support%20under%20Ubuntu.pdf to be useful. It explains how to set up a Python virtual environment (PVE), effectively an isolated Python install that runs independently of the main system's Python. The PVE sounds complicated, but is quite quick to set up if following instructions *exactly*. Essentially you can run different versions of Python, even different configurations of the same version of Python, quite independently of one another.

The instructions on Github are not written from the point of view of a na?ve user. The document in the files area is built on other people's work, and is "obvious", but only *after* one has researched the solution!

You may well need the PVE solution even on Ubuntu &c. 20.04.

HTH, 73, Stay Safe,

Robin, G8DQX

RAR is an alternative to ZIP. There are several free tools that will
handle them. "7-zip" seemed the least atrocious to me. I try to avoid the
fads for compression tools in favor of 1) STANDARDS, and 2) Open source.
The compression advantages are small and the nuisances are big.

Chuck

Pretty good for a man born in BC. And watches came on the seen in 16fh century

Clayton Heilman

"The world is run by those who show up." Richard George Weingardt

In the mid-January, my old 80m dipole broke due to icing and heavy snow. It had a direct connection with a coax for too many years .... and I decided to be with a Choke when the Weater improve.I started tests with several noname ferrite toroids and nanoVNA-H v.3.3. After some measurements (according to Fair Rite ) the toroides turned out to be MgZn, 40x25x11mm with Initial ?i 2000 or a bit more.
Stacked two with 14 turns 1.12 mm enameled wire in thermo shrink tubing (max diameter 2mm - the toroids are small). Normal winding .... tested and Reisert style... the same result.To avoad fixture capacitance I connected the Choke
direct to calibrated plane of nanoVNA CH0 - CH1.
Used nanoVNA alone, after with NanoVNA Saver, and OneofEleven application.
Full House with Data ...I've made a try to burn the choke with my PA and 250W
noninductive dummy load (with some pauses).KEY Down on CW and 175 volts p/p on Tektronix osci.
That is 612 watts on the peaks....The core and windings were cold as before the test ...I know the real test is up on the feedpoint of the antenna....
Seems the Choke can be used on 3.5Mhz- never have had 1.8 Mhz.Only 3.5-432Mhz.
The screenshots are attached.
Will be good some Expert to say something about this Choke....till I waiting for FT240-31 toroids.

Best Regards !

RAR is similar to a zip file- it's an archive with 1 or more files in it.?
You need to extract it's contents.? Use 7zip or another archiving app


On Sun., 7 Feb. 2021 at 9:14 a.m., Jamie WW3S<ww3s@...> wrote: Are there instructions somewhere on how to load the .rar files? I found
them for the DFU files, but the firmware appears to be in the RAR
format.....

Total comander

Are there instructions somewhere on how to load the .rar files? I found them for the DFU files, but the firmware appears to be in the RAR format.....

On Feb 6, 2021, at 2:56 PM, Joe <k1ike_mail@...> wrote:

?On 2/5/2021 6:12 PM, Mel Farrer via groups.io wrote:

Based on 10 MHz, I built up a series SMT structure of a 0603 50 ohm and a 0603 -j50 ohm cap to ground.

I don't understand what you mean by a " 0603 -j50 ohm

Believe he is referring to a 0603 size chip cap that has 50 ohms reactance at 10 MHz .

-Ray WB6TPU

Ah, Confucius say man with two watches don’t know what time it is.

I downloaded nanovna-saver from github and tried to run the program under kubuntu (ubuntu).

python3.7 nanovna-saver.py
Traceback (most recent call last):
File "nanovna-saver.py", line 21, in <module>
from NanoVNASaver.__main__ import main
File "/home/ken/RadioStuff/VNA/NanoVNA/nanovna-saver/NanoVNASaver/__main__.py", line 33, in <module>
from PyQt5 import QtWidgets, QtCore
ImportError: cannot import name 'QtWidgets' from 'PyQt5' (/usr/lib/python3/dist-packages/PyQt5/__init__.py)

I'm no python expert, not sure how to solve this. Looks like some package is missing.

On 2/5/2021 6:12 PM, Mel Farrer via groups.io wrote:

Based on 10 MHz, I built up a series SMT structure of a 0603 50 ohm and a 0603 -j50 ohm cap to ground.

I don't understand what you mean by a " 0603 -j50 ohm cap" Would you please clarify this?

Thanks,
Joe

w2aew on YouTube has some good videos of using the NanoNVA. And lots of other stuff.
Use NanoVNA to measure coax length - BONUS Transmission Lines and Smith Charts, SWR and more:



How to Measure the impedance of "unknown" coax using a NanoVNA:

Gyula HA3HZ,
I read somewhere that A man with a clock always knows what time it is.
A man with two or three clocks can never be sure.....................
So in review, I'd say that you're right on the money!


Ron
WRKM750

David Eckhardt <davearea51a@...> added folder /PROCEDURE FOR MEASURING DM LOSS THROUGH COMMON MODE CHOKES

---

The following files have been uploaded to the Files area of the [email protected] group.

• /PROCEDURE for MEASURING CMC DM LOSS - 30 JANUARY 2021.pdf

By: David Eckhardt <davearea51a@...>

Description:
PROCEDURE FOR MEASURING DM LOSS THROUGH BIFILAR WOUND COMMON MODE CHOKES USING THE NANOVNAs

It was requested by a number of responders that I convert to PDF. The
attachments are in .PDF format which should be able to be read by
everyone.

There was also a request to place them in the files section of these
NANOVNA sites. I am a member and will attempt that. However, if the
moderators don't see them there, please place them there.

Dave - W?LEV

On Fri, Feb 5, 2021 at 10:03 AM, Brad Thompson wrote:

NWT70 analyzer

In the HackRF, the majority of the circuit needs to be protected from excursions outside the 3.2v rail voltages. The two diodes near the input achieve this, allowing excursions from the mid-point (set by the 10K resistors) to below -0.7v or above 3.2+0.7, a peak excursion of 2.3v from the centre in either direction.

The LNA needs additional protection when it is switched into the circuit, which is what the diode to ground achieves.

This use of these limiter diodes is a bit off-label, more like you'd use traditional diode clamps. I couldn't use inductors because it's not possible to find inductors that actually act like inductors over the range from 1MHz-6GHz.

I did not have the budget to prototype this and destroy multiple HackRFs in pursuit of exact data on RF immunity, but there have been zero failure reports from any users of the first batch of 1000 units sold. Time will tell, but compared with a typical failure rate of over 30% LNAs being killed within the first year, things are going well so far.

That's RandL.com
Randal.com com sells truck stuff.
;B
W5VZB

There's really no more to it than I've said. I use a long coax cable to connect a reference dipole antenna a few wavelengths away to one VNA connector and the antenna to the other. It usually is easiest to connect the antenna under test to S1 so you can observe the match as well.

For a reference dipole I use a tiny rabbit ears that came with my RTL-SDR because it can be adjusted to be resonant at most VHF/UHF frequencies (it came with two sets of elements). It also has a ferrite isolator installed on the cable. Make sure it's oriented correctly and away from other objects and correctly adjusted for the frequency by adjusting the elements for maximum signal at the frequency of interest.

My extension cables are made of RG316 and were bought premade from Amazon. The loss is much lower than RG174.

I use microphone stands, stage lighting stands and camera tripods to support the antennas (whatever works) - sometimes I use small sections of PVC water pipe to extend them to keep the antennas away from the stands.

The results are excellent out-of-doors, but indoors I have to do some trial and error to find measurement locations for both antennas not affected by reflections, but usually find one fairly easily.

The results are only broadly useful, but I compare the performance with another reference dipole in the same location and it's usually good enough to save a lot of time before going to play in the back yard.

Make sure, of course to calibrate the S1 port at the antenna itself first. I usually do a local (short) cable calibration "through", but I probably should experiment with calibrating out the remote antenna. For my purposes, manual comparison with reference is usually enough...

M