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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

John,
IMSAI guy on YouTube as a video

Gary
W9TD

By the way, check tinysa.org on the “Where to Buy” page.

--
Mike, W0IH

TinySA (spectrum analyzer) is available on R and L (Randal.com) for $50. Be wary of clones on other sites.

--
Mike, W0IH

Gary,
Where can I find info on using the tinySA as an rf sniffer? Looked at the video list and on the home page but it is not addressed there.

Thanks,
John
K?JHL

Set bandwidth at maximum (4k on H4), connect antenna to CH1 port, and you can get signal strength in 4kHz range for every measure point.
So if measure on 401 point you can measure in span ?401*4k = 1.6MHz (yes can be little higher) If set span more, you can not get signal data (it can be between 2 points and not measured)

Get a tinySA. Works great for that purpose. You may need shielded loop probe if the interference is caused by current or just the telescoping antenna included and an external LNA to get the best sensitivity. I used it around my house.
Gary
W9TD

For what it's worth, I have a similar OFC dipole setup to what you
describe, and the measurements from my nanoVNA-H4 and my MFJ-226 are almost
identical. So what you are describing is not what I experience; maybe
there is a problem with one of your units.

Has this been implemented for a fix to the issue of protection? I would like to update my unit with the fix.Thank you very much,BillW4MXT

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

And then, all 3 have varying degrees of sensitivity to RFI - you're
measuring an antenna that's outdoors.

This is definitely something to keep in mind when you are testing an antenna at a tower site, like at a repeater site. Other transmitters at the site can affect the readings.

I do antenna testing and certification with an Anritsu Sitemaster analyzer. The Sitemaster has the ability to send a coded signal that it can recognize as a valid test signal. This can eliminate some of the interference (but not always all) at a site during testing. This does affect some testing accuracy. The Sitemaster also has the ability to turn off this coded signal and go into the "CW" mode for greater accuracy.

Just something to keep in mind when using the NanoVNA or other device around other live transmitters.

Joe