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Am 29.05.2020 um 14:08 schrieb Larry Rothman <nlroth@...>:

?Well, it had to happen sooner or later - TomTop.com is selling the S-A-A v2.2 (AKA NanoVNA V2) for $60US right now with what appears to be free shipping.

Unknown if these are the inferior clones that have been mentioned here this week - maybe Gabriel or Hugen can comment?




<Nanovna V2 from TomTop.jpg>

Am 29.05.2020 um 14:08 schrieb Larry Rothman <nlroth@...>:

?Well, it had to happen sooner or later - TomTop.com is selling the S-A-A v2.2 (AKA NanoVNA V2) for $60US right now with what appears to be free shipping.

Unknown if these are the inferior clones that have been mentioned here this week - maybe Gabriel or Hugen can comment?




<Nanovna V2 from TomTop.jpg>

Hi Mark,

at first I didn't understand your question, then it started to dawn, maybe
you have the touch screen doing this thing too. The touch screen is
tensioned or pressed somewhere, or the cover plate is just touching it,
causing the touch screen to be pressed by hand grip.
Please remove the cover on the screen side and perform the operation. If
the error does not occur, it is caused by what has been described above.
If this causes it, place 4 pcs plastic washer between the pcb and the
cover plate and screw it back on.

I hope it helps
73, Gyula HA3HZ

--
*** nothing is permanent only change ( ) ***

Thanks Dave,

I am new to a nanVNA and I think I am doing well with it. I have been
reading documents in the WIKI and elsewhere. You have validated what I
think is still a limited understanding.

I have found ways to make two antennas that cover no bands at all cover
the three bands I use:) Each now has one band it does not like but all
three bands are accommodated now. More improvements to come:)

73,

Bill KU8H

On 5/28/20 8:27 PM, David Eckhardt wrote:

First item to remember is that there are on 101 points across the

specified

frequency range. Therefore, to get any good resolution, use only narrow
band measurements, like only one amateur band at a time. Even on 80/75
meters from 3.5 to 4.0 MHz, that will yield only (roughy) every 5 kHz.

If

you are using this with a shortened mobile whip, this could become a
problem.

If you really do require larger frequency ranges like a couple of MHz, or
even 3 to 30 MHz sweep, use software with a laptop or PC to make the
measurements. NANOVNA-SAVER is good at this and available free from the
NANOVNA bunch. In the upper left corner of SAVER, you will note where

you

set the frequency range or start/stop frequency. Just under that, there

is

a box to specify "Segments". This allows you to divide your specified
frequency range into segments, each containing 101 points. This allows
better resolution spread across your complete frequency range. Set

enough

"Segments" such that you don't miss something in a particularly wide
frequency span. That is an error many new users have made - not enough
setments and miss high-Q features of their measurements. Just remember
each segment contains only 101 points. The "Segment" function is not
available with the stand-alone instrument.

When you calibrate, either on the instrument or using SAVER, that cal. is
good for only the frequency range over which you specify, again WITH the
101 point limit. If you, then, want to measure an antenna in the shack

at

the end of the feedline, you're OK. However you will be measuring the
antenna AND the feedline. It is advised that you measure antennas at the
antenna. If you must measure with the feedline in place, first

disconnect

the feedline from the antenna and re-calibrate at the antenna end of the
feedline. Then re-attach the antenna to the feedline and make your
measurement in the shack at the shack end of the feedline. That way, the
contributions of the feedline will be automatically eliminated from your
measurement.

Calibration of any kind should be completed for each frequency range and
individual and unique setup you wish to measure.

Hope this helps and gets you going.

Dave - W?LEV

On Thu, May 28, 2020 at 6:03 PM Steve Haber <haber.steve@...>

wrote:

First some background:

So I bought a NanoVNA. I'm going to use it for antenna analysis/SWR
setting. I figured out how to download the software updates. I installed
the latest AA software. I did the calibration with the supplied

calibration

ends. All good so far.

While reading everything I can find about testing antennas & SWR, I'm

lost

on when & how to recalibrate it for each antenna &/or coax. Do you need

to

recalibrate it for each type/length of coax/antenna? Assuming the coax &
antenna is 50 ohms, do I use the coax/antenna as the 50 ohm load and

set to

calibration using this, or do I need to purchase PL259 calibration ends

or

what? Also, do I need to enter the coax velocity numbers as well?

I read that if I don't recalibrate the Nano each time, it won't give a
accurate reading.

I could really use some pointers here. I've read & watched a bunch of
videos about NanoVNA antenna testing, but no one covers calibration with
regards to this. The good news is that I can get it to work and give me
results, I just don't know if the readings are accurate.

I'll take any and all help to figure this out & understand what I need

to

do.

Thanks for your help!

Steve

--
bark less - wag more

First item to remember is that there are on 101 points across the specified
frequency range. Therefore, to get any good resolution, use only narrow
band measurements, like only one amateur band at a time. Even on 80/75
meters from 3.5 to 4.0 MHz, that will yield only (roughy) every 5 kHz. If
you are using this with a shortened mobile whip, this could become a
problem.
If you really do require larger frequency ranges like a couple of MHz, or
even 3 to 30 MHz sweep, use software with a laptop or PC to make the
measurements. NANOVNA-SAVER is good at this and available free from the
NANOVNA bunch. In the upper left corner of SAVER, you will note where you
set the frequency range or start/stop frequency. Just under that, there is
a box to specify "Segments". This allows you to divide your specified
frequency range into segments, each containing 101 points. This allows
better resolution spread across your complete frequency range. Set enough
"Segments" such that you don't miss something in a particularly wide
frequency span. That is an error many new users have made - not enough
setments and miss high-Q features of their measurements. Just remember
each segment contains only 101 points. The "Segment" function is not
available with the stand-alone instrument.
When you calibrate, either on the instrument or using SAVER, that cal. is
good for only the frequency range over which you specify, again WITH the
101 point limit. If you, then, want to measure an antenna in the shack at
the end of the feedline, you're OK. However you will be measuring the
antenna AND the feedline. It is advised that you measure antennas at the
antenna. If you must measure with the feedline in place, first disconnect
the feedline from the antenna and re-calibrate at the antenna end of the
feedline. Then re-attach the antenna to the feedline and make your
measurement in the shack at the shack end of the feedline. That way, the
contributions of the feedline will be automatically eliminated from your
measurement.
Calibration of any kind should be completed for each frequency range and
individual and unique setup you wish to measure.
Hope this helps and gets you going.
Dave - W?LEV
On Thu, May 28, 2020 at 6:03 PM Steve Haber <haber.steve@...> wrote:

First some background:

So I bought a NanoVNA. I'm going to use it for antenna analysis/SWR
setting. I figured out how to download the software updates. I installed
the latest AA software. I did the calibration with the supplied calibration
ends. All good so far.

While reading everything I can find about testing antennas & SWR, I'm lost
on when & how to recalibrate it for each antenna &/or coax. Do you need to
recalibrate it for each type/length of coax/antenna? Assuming the coax &
antenna is 50 ohms, do I use the coax/antenna as the 50 ohm load and set to
calibration using this, or do I need to purchase PL259 calibration ends or
what? Also, do I need to enter the coax velocity numbers as well?

I read that if I don't recalibrate the Nano each time, it won't give a
accurate reading.

I could really use some pointers here. I've read & watched a bunch of
videos about NanoVNA antenna testing, but no one covers calibration with
regards to this. The good news is that I can get it to work and give me
results, I just don't know if the readings are accurate.

I'll take any and all help to figure this out & understand what I need to
do.

Thanks for your help!

Steve

First some background:

So I bought a NanoVNA. I'm going to use it for antenna analysis/SWR
setting. I figured out how to download the software updates. I installed
the latest AA software. I did the calibration with the supplied calibration
ends. All good so far.

While reading everything I can find about testing antennas & SWR, I'm lost
on when & how to recalibrate it for each antenna &/or coax. Do you need to
recalibrate it for each type/length of coax/antenna? Assuming the coax &
antenna is 50 ohms, do I use the coax/antenna as the 50 ohm load and set to
calibration using this, or do I need to purchase PL259 calibration ends or
what? Also, do I need to enter the coax velocity numbers as well?

I read that if I don't recalibrate the Nano each time, it won't give a
accurate reading.

I could really use some pointers here. I've read & watched a bunch of
videos about NanoVNA antenna testing, but no one covers calibration with
regards to this. The good news is that I can get it to work and give me
results, I just don't know if the readings are accurate.

I'll take any and all help to figure this out & understand what I need to
do.

Thanks for your help!

Steve

Touchstone rep told us years ago, 80286 time, that PC version will be able
to simulate the whole PCB and its currents, when PC gets a few egabytes
more RAM. Well, I am still waiting.

On Thu, May 28, 2020 at 04:34 AM, <david.hostetler@...> wrote:

The high impedance output of this balun is center tapped and the center

tap is

grounded back to the input SMA (unless you cut the small trace on the

back of

the PCB). When you connect one side of the output to the coax shield

going to

the VNA, you short the winding!

Hello David and Roger,
This was the solution. Thank you very much for the hint.

I have the schematic of the balun, but I did not consider the R1 jumper.
II cut the R1 jumper on the lower side of the PCB and calibrated from 50
KHz to 100 MHz.

Now it works as expected, see NooElelc_Balun_9-1_S21_Loss.png.
And the reference from NooElect:
balun_one_nine_insertion_loss_comparison_to_70mhz.png
And the setup: RF_Balun_1-9_S11_DSC08237.jpg

So, it is proved, that with a 400 Ohm resistor and a SMA plug you can
measure the *Insertion Loss*.

73, Rudi DL5FA