开云体育

From A Common User's Point of View

Sorry for question, but what means word "facupov"?
It is often mentioned here, but I cannot understand what you're talking about...

Just tried to google it, but unfortunately with no success

From: Ady, YO2NAA: Your suggestion to use a USB extender is a good one, thank you.

What about RF on the USB cable?

Rune,

I attached a screen shot of the image you ask for. That is a full screen of a scan I saved. I noticed when I first loaded the file the image fit the screen perfectly but when I added Marker3 the image changed size to where you see it.

I fi I can supply any additional information will do my best to do so. This is running Win7 with the latest upgrades.

73,

Wes
WA5TKU

If you have calibration data as impedance and delay, but want S11 s1p format,
then VNWA software can generate it, according to Kurt Poulsen.

in the VNWA software you simply open a custom trace

I did not expect this "simply" to be so tricky. It appears that
VNWA documentation >>never explains<< how to open a custom trace window.

Help has a section about what to do when already in custom sweep window,
but getting there may be something that lucky folks are born already knowing...

Also, Frequency Range, under Settings, >>does not set Start and Stop<<, only Linear vs Log vs Listed...?

I guess this software may discourage many from purchasing the supported hardware.

The answers:
* right-click mouse button in the main window and select Trace Options,
which launches a dialog box titled 'Display Settings'
Custom is selected by scrolling down in small box next to color sample for Trace 1-6

* left double-click near Start or Stop frequencies will launch 'Input' dialog box
to set those frequency values. Sweep Mode is also selected here,
making Frequency Range option in main window Settings less than useful.

in the Expression line write s_load or s_open or s_short or s_thrumatch or s_thru
then the trace is shown according for the custom trace to be shown
as you like in Smith, dB of what ever representation
then to save directly as s1p file by a right click on the trace and use the "Export to s1p file" function.

Well, right-click on trace launches another dialog box, but no options for saving it

I don't entirely agree, Erik. GitHub issues can easily be marked as
"enhancement" - I certainly use that a lot to weed out what I need to work
on, and what's optional. As long as you're polite, descriptive, and don't
expect a response from a busy author, adding feature requests can be fine.

I do note that both edy555 and hugen79 could benefit from setting up bug
and feature request templates on their respective githubs, to make it
easier to distinguish.

--
Rune / 5Q5R

PLEASE only give feedback on what is supposed to work but does not.
Don't submit hundreds of new feature requests as there is only one hugen79 and one edy555 (ttrftech)
Github can not be used as some kind of voting system for new features. There exits better solutions
--
Erik, PD0EK

That UTP cable is just as much detuning your antenna by common mode current as
feeding the antenna by coax without balun would do.
Common mode current via the NanoVNA and the UTP cable to ground has just the
same detuning effect.

That detuning should be investigated;
I suppose it depends on match between nanoVNA and antenna.
For antennas typically using a balun to feed coax, then nanoVNA should have the same.

Perhaps running several turns of cat6 thru a ferrite core near the nanoVNA would mitigate.
Supposing that one has some other indication of antenna tune at the shack end of coax,
could useful experiments to minimize nanoVNA + USB-via-cat 6 impacts
be conducted with antennas conveniently lowered?
I have no feel/experimental results for Yagi proximity to earth...

I am wondering what mechanism causes S11 impact depending on a cable (the
rotation speed versus frequency is roughly proportional with the length of the
cable) but with a different rotation speed?
I'm observing a sin(f)*e(f) effect
Could this be the cable capacitance????

Rotations are mostly by cable delay,
and I guess that differences from 180 degrees
between rotations for open and short measurements
are provoked by non-ideal open and short calibration characterization.
This can be simulated e.g. @ 5 MHz with 2m LMR-400
by substituting 3.5 wire turns for short and 390pf for open.

I intend to experiment for reducing this using VNWA software..

Hi Andy,


I cannot support your last statement:

> The UTP cable will have some influence on the antenna but not important I think

That UTP cable is just as much detuning your antenna by common mode current as feeding the antenna by coax without balun would do.
Common mode current via the NanoVNA and the UTP cable to ground has just the same detuning effect.

If in doubt, see attached powerpoint.

NanoVNA grounding by holding it in your hand can be avoided by mounting it on a PE board as shown in the pic.
The 6mm PE board was hot air bent a bit in a vice, because of the inclined SMA connectors. The PE board was
left long for holding it without touching the NanoVNA. Insulation is more practical than needing a suitable balun
for each antenna situation.

73, Hans
DJ7BA



-----Ursprüngliche Nachricht-----
Von: [email protected] <[email protected]> Im Auftrag von Ady, YO2NAA
Gesendet: Montag, 4. November 2019 15:12
An: [email protected]
Betreff: Re: [nanovna-users] Storing and recalling scan later via Nano VNA saver (or similar) #internals #consolecommands

Usually, the distance to the antenna feed point is 15-20m in my case, but it can be more on high towers.
Your suggestion to use a USB extender is a good one, thank you. It will work great for YAGIs on a pole.

However, in the case of a wire dipole, all the UTP cable weight will put a heavy load on the NanoVNA's USB and SMA connectors, unless the UTP cable is tied up to the antenna using nylon rope. The UTP cable will have some influence on the antenna but not important I think.

On Mon, Nov 4, 2019 at 3:45 PM Oristo <ormpoa@...> wrote:

Install the antenna on the working position

How distant is working position?
USB extender up to 150ft costs < US$10

--
Diese E-Mail wurde von Avast Antivirus-Software auf Viren geprüft.

Hi Wes,
can you send me a screenshot? There shouldn't be any problems fitting in
900 pixels vertical space, unless you're running a lot of markers, or quite
a large font...

--
Rune / 5Q5R

Usually, the distance to the antenna feed point is 15-20m in my case, but
it can be more on high towers.
Your suggestion to use a USB extender is a good one, thank you. It will
work great for YAGIs on a pole.

However, in the case of a wire dipole, all the UTP cable weight will put a
heavy load on the NanoVNA's USB and SMA connectors, unless the UTP cable is
tied up to the antenna using nylon rope. The UTP cable will have some
influence on the antenna but not important I think.

How about connecting a Pi or summat running *nix and Python.
Not an expert w either one, but have tinkered w the Pi

A Pi with Python


.. should be able to run a hack of this:


in bash shell scripts for such special case measurements

I was fortunate enough to get some high-quality PTFE (Teflon) coax (RG-174
sized) SMA to BNC jumpers - and these hold up much better, probably because
they have a small piece of heat-shrinkable tubing at the interface between the
connector and the cable which distributes stress over a larger area

These have heat shrink (one layer) twice the length of crimp ferrules;
34cm is longer than typically needed,
so splurged another ~ US$6.50 on four more with 15cm length.

A source for durable pigtails would be good to know.

Rich,

Current calibration is calculated per frequency point so no relation whatsoever with any other point in the scan.
See here:
/g/nanovna-users/wiki/Application-Notes
for the harmonic switch frequencies

I do see however very different behavior once the nanoVNA switches to harmonics mode but this does not influence the regular calibration currently implemented.

At low frequencies the bridge correction model is fairly easy as its impact is in sync with the rotation of the S11 angle. At higher frequencies the observed impact gets out of sync with the observed S11 angle so I am wondering what mechanism causes S11 impact depending on a cable (the rotation speed versus frequency is roughly proportional with the length of the cable) but with a different rotation speed?
I'm observing a sin(f)*e(f) effect
Could this be the cable capacitance????
--
Erik, PD0EK

Install the antenna on the working position

How distant is working position?
USB extender up to 150ft costs < US$10

On Sun, Nov 3, 2019 at 04:07 PM, Clint Turner wrote:

If I could, I would put more heat-shrinkable tubing on them, but this is
difficult with the already-attached connectors.

I have used two alternatives: wrappable heat shrink and Silicone Rubber Self Fusing Tape. The tape come in different thicknesses and widths. A life-saver during some high-altitude balloon missions, because it goes on by itself in the field.
Not as much luck with the wrappable stuff, but if you have some shrink tubing with a high shrink ratio, you can pre-wrap with other material, the slide a larger sleeve over. I have done this, and admit that it can look clunky, but function wins over form for me here.
--
On the banks of the Piscataqua
Rich NE1EE

The ability to resize to fit the display would be a great improvement. My laptop has a 17" display running at 1600x900 but still have the scroll bar for vertical position of the chart. It would be nice not to need to modify my screen settings.


Thank you for all the hard work you put into the software for the Nanno VNA.

73,

Wes
WA5TKU

This may be because it doesn't work on v6x, or maybe the authors have not
configured the page correctly?

The author does not own older Android, so configured the app support for his versions.

you are probably correct, my older android is ver7