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Ok new question.
I'm following the setup in the beginner's guide for process of calibration, get it done according to the guide and try to verify with the Smith chart . I screw my open to port 1 trace 1 (trace 0 is my swr trace) were I did the calibrate and according to the guide it should go to the far right of the Smith chart. It dont, it just sits in the same place. What am I doing wrong here?
I'm following it step by step!

On Sat, Jun 10, 2023 at 11:44 AM, Jim Lux wrote:

Jim Lux,

I got a break from TDR by seeing "Swan Lake" , enjoyed the music , not sure about the ballet.
My XYL comment was "woman body legs are not attached to the body..."

BTW the antenna "mast" fell in recent windstorm, dummy forgot to add hose clamp to the first cammo pol;e and it broke .
No damage to anything, just pride.

I found a short piece of same, labelled RG6 cable so I can compare it with the unlabeled one.

I need to go back to grammar school and study Fourier to make sense of all of this.

I still believe the nanoVNASaver has an issue with using the "sweep" entries...
Also the "TDR" and the TDR display options do not match - the "POP up sub menu in particular.

PS
During my college study there was a joke going around with one of the professors pet question
"draw me a graph..."... if you forgot to add dimensions to either axis you have failed the exam.
TDR graph is missing the "y axis" dimension.
73 Vaclav AA7EJ

of this.

Thanks, all reposes are greatly appreciated.
73 Vaclav AA7EJ

The USB-C port on the NanoVNA systems is reported to be rudimentary, and
not capable of properly negotiating the voltage it wants. 5 Volts is
expected.
Use a USB-A to USB-C cable and this won't usually be an issue. Some cases
where the computer fed far too much voltage than the Nano could accept have
apparently fried the Nano, so be careful.
73,
-Rick

On Sun, Jun 11, 2023 at 8:46?AM Oddleiv Tungland - LA3GW <Oddleiv@...>
wrote:

s?n. 11. juni 2023 kl. 14:27 skrev Oddleiv Tungland <oddleiv@...>:

the display starts to flicker.

-Oddleiv

--
Rick Murphy, D. Sc., CISSP-ISSAP, K1MU/4, Annandale VA USA

Please do not put the text of your post in the Subject line. The Subject line should refer to the general topic about which the post is intended. Some recent posts have had ridiculously long subject lines, which is not only uneccessary but don't format well, particularly on small devices.

For example:

Wrong:
Subject: How do I load the xyz firmware onto my nanovna when I am upgrading fom version pqr?

Message: I am currently running version pqr firmware on my nanovna. How do I load the xyz firmware onto my nanovna when I am upgrading fom version pqr?

Right:
Subject: Upgrading nanovna firmware

Message: I am currently running version pqr firmware on my nanovna. How do I load the xyz firmware onto my nanovna when I am upgrading fom version pqr?

A contrived example, for sure, but hopefully you get the point. Please think about this when you post a new message.

Thank you.
DaveD

s?n. 11. juni 2023 kl. 14:27 skrev Oddleiv Tungland <oddleiv@...>:

the display starts to flicker.

-Oddleiv

added a bluetooth module

H / H4 / LiteVNA allow install Bluetooth or WiFi to serial module (deivices have internal serial connection pins) for use wireless connect.
I test bluetooth HC-05, HC-06 moduless (maximum speed depend from module revision) and get up to 460800 baudrate.

PS wireless communication increases measurement noise, especially WiFi

On Sat, Jun 10, 2023 at 11:16 AM, Siegfried Jackstien wrote:

added a bluetooth module to my sark100 and can now measure "wireless" (use
smartphone to display sweeps)

A few years ago, before the nanovna, I bought the MINI60 version of the Sark.
It's very small, it sweeps the band you choose, shows the frequency of minimum SWR but you can also read each measurement of the sweep. Mine has the built-in bluetooth module, and works with my Android phone. And it IS readable in sunlight!
They currently cost around $120, though. About the price of the nanovna-h4 or -F.
It's in my Harbor Freight plastic "ammo box" case with the Nanos and an MFJ-207 analyzer. I am still glad to have it.
--
Doug, K8RFT

On 6/10/23 7:34 PM, Jim Shorney wrote:

The wayback machine has it.

The 39B2 link below the text leads to a PDF.
73
-Jim
NU0C

foam, 82% VF

The wayback machine has it.



The 39B2 link below the text leads to a PDF.

73

-Jim
NU0C

On Sat, 10 Jun 2023 13:07:27 -0700
"Anne Ranch" <anneranch2442@...> wrote:

I did ask Mts Goggle and got no (real) answer

Here is the label on the cable

Eagle Aspen 39B2 RG-6 2.25 GHz Digital Coaxial Cable, 6FT, Black, High Performance 2.25 GHz CMX 18AWG 75°C UL E227171

Please share if you know the velocity factor - VF .

Thanks

On 6/10/23 1:07 PM, Anne Ranch wrote:

I did ask Mts Goggle and got no (real) answer
Here is the label on the cable
Eagle Aspen 39B2 RG-6 2.25 GHz Digital Coaxial Cable, 6FT, Black, High Performance 2.25 GHz CMX 18AWG 75°C UL E227171
Please share if you know the velocity factor - VF .

You might be able to figure it out from the 18 AWG (which is the diameter of the center conductor). The Z depends on the ratio of inner to outer diameter AND the epsilon of the dielectric.

OTOH, who's to say that the center conductor really is 18 AWG.

You might also be able to figure it out from the loss vs frequency.

Or, perhaps, the mfr's website (which doesn't seem to go anywhere.. they may be out of business?)

Since I saw some google references to it being used for satellite TV, I'm going to guess it's foam dielectric. Lower dielectric losses for higher frequencies.

But testing a sample is the only way you'll know, if you can't get the mfr data sheet.

If you have a sample and you cut it open, you'll know. foam looks different than solid.

How long is it?

Can you measure how long it is, then use the nano to see how long "Electrically" it is,
and there ya go you got it's VF.

Joe WB9SBD
.

A Contest 40 Years in The Making!
<>
MAIDENHEAD MAYHEM

On Sat, Jun 10, 2023 at 01:07 PM, Anne Ranch wrote:

Eagle Aspen 39B2 RG-6 2.25 GHz Digital Coaxial Cable, 6FT, Black, High
Performance 2.25 GHz CMX 18AWG 75°C UL E227171

Please share if you know the velocity factor - VF .

It is foam dielectric with VF of 82%

Roger

I am not sure I have another scrap cable I can take apart, This one has been given to me and I do not have same crimp connector to cut / restore it.

Is there any way to tell if the dielectric is PE or foam?

73,
Joseph W6JHP

I did ask Mts Goggle and got no (real) answer

Here is the label on the cable

Eagle Aspen 39B2 RG-6 2.25 GHz Digital Coaxial Cable, 6FT, Black, High Performance 2.25 GHz CMX 18AWG 75°C UL E227171

Please share if you know the velocity factor - VF .

Thanks

Sigi:

Did you write anything up or have pictures of your Bluetooth add-on.

I’d like to give it a try.

Thanks

Ed McCann
AG6CX

On 6/10/23 11:22 AM, Anne Ranch wrote:

Jim Lux,
as always, your replies are clearing few of mine misconceptions, thanks.
With all this FFT (frequency to pulse and time ) it is still unclear how CHANGING the "sweep" changes the "estimated cable length".
...and how it still "calculates" the cable length AFTER it is hooked to the actual load / antenna (variable with frequency ) - assuming that TDR can be calculated from open , shorted and "real terminated" but unknown and variable with frequency termination.

The open/short/load just makes sure the reflection measurement is correct. It has nothing to do with the actual measurement of a feedline.

The reason you can "see" connectors and the antenna in the TDR is that they are not exactly the same impedance, so you see the discontinuity. If you had a single length of coax, and a load that was well matched to the coax, you probably wouldn't be able to measure the length.

Think of it as estimating the size of a room with your eyes closed by listening how long it takes for the echo to come back when you clap your hands. Easy in a boxlike room with hard walls. Impossible in an acoustically dead room, because the sound just goes out and is absorbed.

It is the rare antenna that is matched at all frequencies. So even it's a good match (and has no reflection) at a few frequencies, for most of the other frequencies, it reflects back significant energy. And that's enough to make the TDR work.

To kind of use a different conceptual view, imagine that you measure the phase shift (and ignore amplitude) for a series of frequencies. You plot those on a graph (unwrapping where needed), and then fit a straight line to the points. The slope of that line corresponds to the length of the cable. And even if there's some missing points (because the amplitude is small where the antenna is well matched) you can still fit the line. So you get a more accurate measurement - sort of like averaging.

The cool thing about the FFT approach or the "fit a straight line" (versus the "look for zero or 180 phase in the reflection and it's a multiple of 1/4 wavelength" ) is that it combines multiple measurements into what you want - the delta phase vs delta frequency. (FWIW, Delta phase/delta frequency is "group delay")

It also lets you know if you're measuring something that's dispersive (where the delay varies with frequency), because then, the plot of phase vs frequency won't be a straight line. That's important for things like waveguides, ionized media, traveling wave tube amplifiers, etc - because a group delay that's not flat means that pulsed waveforms will be distorted.

With real load connected the calculation must include "real load" somehow...

On 6/10/23 11:04 AM, Roger Need via groups.io wrote:

Those interested in how the TDR was implemented in NanoVNA Saver will find the details in this groups.io post by Herb Walker.
/g/nanovna-users/message/9651
For more details on how the S11/IFFT method of TDR works this tutorial by Agilent is quite informative. It includes details on why "windowing" the data is necessary, how to determine the upper stop frequency required based on estimated cable length, why the lower start frequency should be close to DC and other considerations.

Roger

The Keysight Ap Note is a good reference.

For what it's worth, in the older NanoVNA-Saver version I have, there are some problems in the implementation, specifically because it does not deal with the "non zero" starting frequency. If you set 10 MHz to 60 MHz sweep, I don't know that you'd get the right results, because it just assumes that you're feeding the IFFT evenly spaced points from 0-{highest freq}.

It is possible that when you select TDR mode it changes how it builds the measurement segments so that the lowest frequency is equal to the spacing between frequencies, and then puts in a zero for the DC term.

I do know that the Keysight boxes (e.g. the fieldfox) do handle both lowpass and bandpass correctly. When you pay $20k, that's something you get. For other applications, with uneven spacing, I've written code to deal with it.