Rune has the S11 values converted to Z series complex, real and imaginary.
He provides the Q as well and this is the Q series value.
You can transform from series to parallel and he does this correctly by using the formula:
Rp=Rs (Qs^2+1).
The series and parallel network equivalent must have the same Q, hence Qs = Qp.
Then to find the equivalent parallel form as well the series Imaginary form just use the appropriate Q equations, namely:
Qs=Xs/Rs and Qp=Rp/Xp. Hence the X values are found and dependent on the SIGN, choose L or C for the final result.
Alan
|
Hi Maurizio,
I'm glad you're enjoying the new version :-)
I agree that calibrations should save the start/stop/segments/averaging.
It's a great point. I don't know if I want to overwrite whatever frequency
span the user has set up when they load the calibration, though. It's a
matter of doing what the user expects, and I'm not sure I would expect
loading a calibration to change my sweeping setup? That's my thought for
now, at least.
Showing the marker values on the charts themselves for the values displayed
on the chart is an interesting idea. I will put it on the list of new ideas!
--
Rune / 5Q5R
toggle quoted message
Show quoted text
On Thu, 17 Oct 2019 at 15:29, Maurizio IZ1MDJ <redifon500@...> wrote: Hi Rune , very happy for the new improvement on the 0.1.3 of nanovna-saver.
Suggestions for the future version :
1 Save the settings of nanovna , start stop center number segments , sweep
mode , when saving the calibration ,not necessary as separate file , better
in the same file. Recalling calibration file , the parameters will be
update automatically.
2 Have a marker over the graphic for the main parameter , as a choice
instead to display all data.
Many thanks again for your effort to improve the SW that is making the
nanovna a very powerfull piece of hardware.
Best regards
Maurizio IZ1MDJ
|
Hi Martin, I *think* the Cs/Ls you are after is already shown in the marker data display? It's what's shown as "L equiv."/"C equiv." The series resistance is the resistive part of the impedance display. -- Rune / 5Q5R On Thu, 17 Oct 2019 at 14:51, Martin via Groups.Io <martin_ehrenfried= [email protected]> wrote: On Wed, Oct 16, 2019 at 09:22 PM, Martin wrote:
I've got some other info that may be of help, but I can't find the
document at
the moment.
Hi Rune,
I still can't find my old paper notes on the subject of Cs, Cp, Ls and Lp
but this Keysight document seems to be the closest to what I was looking
for.
Section 1 of this document
Section A1-5 of the following is also useful and Table A1-3 in this
document define the various formulae
Regards,
Martin - G8JNJ
|
Re: Adapters, SMA to N and BNC.
A source of inexpensive 50 Ohm adapters.
Free shipping, if you don't mind waiting for a slow boat from China:
1) SMA male to SMA male: $1.20
2) SMA male to SMA female: $1.20
3) SMA male to RPSMA female: $1.10
4) SMA female to SMA female: $0.99
5) SMA male to BNC male: $1.30
6) SMA female to BNC male: $1.10
7) SMA male to BNCF female: $1.10
8) SMA female to BNC female: $1.20
9) SMA male to N male: $1.65
10) SMA female to N male: $1.65
11) SMA male to N female: $1.75
12) SMA female to N female: $1.75
13) SMA male to UHF male (PL-259): $1.75
14) SMA male to UHF female (SO239): $1.75
15) SMA fmale to UHF male (PL-259): $1.75
16) SMA female to UHF female (SO239): $1.65
17) RP-SMA male to N male: $1.70
18) RP-SMA male to N female: $1.75
19) RP-SMA female to N male: $1.80
20) RP-SMA female to N female: $1.80
N0YWB
|
Hi Norbert,
I'll definitely not make a flexible display window for now, as the way the
charts are built is not at all compatible with this approach - sorry! Maybe
in a far future when everything is refactored. :-)
Making a plot of both S11 and S21 LogMag on the same chart wouldn't be too
much work, so I might be able to do that. I'll put it on the list!
--
Rune / 5Q5R
toggle quoted message
Show quoted text
On Thu, 17 Oct 2019 at 10:20, <norbert.kohns@...> wrote: Hi Rune,
I have a suggestion. If one tries to adjust a homebrew filter of any kind
it would be very helpful to see the result of the adjustment at least for
S21 and S11 simultaneously on one plot. In other words, could you please
make a flexible window where one could select various data to be displayed
on that window simultaneously?
Kind regards
Norbert, DG1KPN
|
Re: NanoVNA WebApp USB question
Hi,
I used to work for a passive component manufacturer. Had a tiny experience
with 0402. Hearing aid manufacturer used an 0402 cap to stop GSM
interference. Soldered by hand under a magnifyer. Watched the assembly
ladies making it look easy. Me? No chance! I was in my twenties then and
I'm 51 now.
Later I saw 0201 and then 01005! Static charges made those samples stick to
the packaging.
Paul
toggle quoted message
Show quoted text
On Thu, 17 Oct 2019, 15:53 W5DXP, <w5dxp@...> wrote: From: sala nimi: Some people said that you can solder anything you see, so get a magnifying glass.
"Some people" have never experienced familial palsy.
|
Erik,
How much noise is being produced by the LCD refresh?
Are you able to run tests with it against the PCB and unfolded out to the side away from the SMA connectors?
Can you disable the LCD routines and see how the noise changes? (access via console only).
...Larry
toggle quoted message
Show quoted text
On Thursday, October 17, 2019, 1:32:19 p.m. GMT-4, erik@... <erik@...> wrote:
Using the console command "sample" it is possible to measure the pure reference, refl and thru signal strength.
First picture shows the change over frequency of the reference signals (only look at the changes in level, the absolute levels differ due to some TAPR VNA internals)
According to the internal gain setting table in the nanoVNA there is additional gain added as the frequency moves up. These are the? vertical jumps, each about 5dB at 300, 600,900, 1200, 1500 and 1800MHz. In total about 45dB gain is added in the audio path to compensate for signal loss and with the 10dB delta between lowest and highest frequencies the delta is 55dB, similar to the 55dB measured with the direct connection to the SA612 so the nanoVNA adc and dsp algorithm do maintain the dynamic range.
Next picture shows what happens when you use a clean 5V supply. Much less noise in the reference signal.
The weird thing with the reference signal is the increase in strength above 1.5GHz. This could be caused by capacitive coupling in the attenuator before the reference mixer
Third picture is the change of the amplitude signal (red line) of reflection mixer without anything connected to the SMA CH0 connector, a fairly good open. The change of amplitude over frequency does not show any weird things. The green line shows the leakage from the output signal into the forward mixer. The pattern suggest the attached cable acted like an antenna
The fourth picture is the change of the amplitude of the forward mixer. (green line) with a through from CH0 to CH1.
The bridge (red line) stops working above 1.5GHz as the characteristic pattern of the cable disappears, possibly because of insufficient measurement SNR
Till now I have not been able to get valid phase signal from the bridge above 1.5GHz, only amplitude with at least 20% noise.
Comparing the absolute levels of the signals suggests there is about 10dB headroom for increasing the thru signal and about 20dB for increasing the reflection signal. In particular the latter might? have a big impact in the performance of the bridge at higher frequencies.
I hope this information is not too detailed but writing it down helps me to understand it much better.
|
Re: Problem with cho45 web interface
Best thing to do is open an issue on cho45's github repo:?
BTW, I see the same security message.
toggle quoted message
Show quoted text
On Thursday, October 17, 2019, 2:06:33 p.m. GMT-4, dk1vi <dk1vi@...> wrote:
Whenever I start from within Chrome browser I get a short message at the bottom flashing up with message "Security error: must be handling a user gesture to show a permission request".
When trying to connect another message appears "Type error cannot read type "1" of null".
I use hugens latest firmware dated 20191009. No problem with NanoVNA saver.
Any ideas?
|
Problem with cho45 web interface
Whenever I start from within Chrome browser I get a short message at the bottom flashing up with message "Security error: must be handling a user gesture to show a permission request".
When trying to connect another message appears "Type error cannot read type "1" of null".
I use hugens latest firmware dated 20191009. No problem with NanoVNA saver.
Any ideas?
|
Using the console command "sample" it is possible to measure the pure reference, refl and thru signal strength.
First picture shows the change over frequency of the reference signals (only look at the changes in level, the absolute levels differ due to some TAPR VNA internals)
According to the internal gain setting table in the nanoVNA there is additional gain added as the frequency moves up. These are the vertical jumps, each about 5dB at 300, 600,900, 1200, 1500 and 1800MHz. In total about 45dB gain is added in the audio path to compensate for signal loss and with the 10dB delta between lowest and highest frequencies the delta is 55dB, similar to the 55dB measured with the direct connection to the SA612 so the nanoVNA adc and dsp algorithm do maintain the dynamic range.
Next picture shows what happens when you use a clean 5V supply. Much less noise in the reference signal.
The weird thing with the reference signal is the increase in strength above 1.5GHz. This could be caused by capacitive coupling in the attenuator before the reference mixer
Third picture is the change of the amplitude signal (red line) of reflection mixer without anything connected to the SMA CH0 connector, a fairly good open. The change of amplitude over frequency does not show any weird things. The green line shows the leakage from the output signal into the forward mixer. The pattern suggest the attached cable acted like an antenna
The fourth picture is the change of the amplitude of the forward mixer. (green line) with a through from CH0 to CH1.
The bridge (red line) stops working above 1.5GHz as the characteristic pattern of the cable disappears, possibly because of insufficient measurement SNR
Till now I have not been able to get valid phase signal from the bridge above 1.5GHz, only amplitude with at least 20% noise.
Comparing the absolute levels of the signals suggests there is about 10dB headroom for increasing the thru signal and about 20dB for increasing the reflection signal. In particular the latter might have a big impact in the performance of the bridge at higher frequencies.
I hope this information is not too detailed but writing it down helps me to understand it much better.
|
Re: errors of "error" models
#53 : Upgrade : The [LeastVNA] - after: #48 : ann : update 3 of [LeastVNA] is withdrawn 15 October 2019 /g/nanovna-users/message/4945 - Hello, Allow us, please, to inform you that we just finished our research regarding the [LeastVNA] description of [AnyVNA], which from now on exists in our small objective world as the one given by this 39 characters long expression: Thank you very much indeed all of you who constructively commented on this crucial matter ! Sincerely, gin&pez@arg 53#
|
Re: Owen Duffy on improvised test fixtures
#test-jig
|
Re: Owen Duffy on improvised test fixtures
#test-jig
I have made a test jig for my VNA based on a ZIF socket. I always measure
with the ZIF socket closed, even if nothing is locked into it. A short is
literally a tiny piece of wire a couple of mm long. The open is no wire,
and the load is a 1/8 watt 50 ohm resistor. The ground is soldered to one
row of the ZIF socket, port 1 is half the pins on the other row, and port 2
is the other half, so that the two ports only need to be bridged by about
2.5 mm to obtain the short measurement.
toggle quoted message
Show quoted text
On Thu, Oct 17, 2019 at 11:15 AM W5DXP <w5dxp@...> wrote: Martin
5:37am #5091
Martin - G8JNJ wrote: Owen is one I'd always listen to, even if personally challenged by what he has said or written. It's happened to me,
I've learnt a lot in the process, and continue to respect him.
Ditto for me. After I decided to ignore the irrelevant emotional content,
I learned a lot from Owen Duffy.
|
When using the nanoVNA at frequencies above 300MHz it switches to harmonics mode
First attached picture shows the harmonics till 1600MHz of the SI5351 output when set at 100MHz.
The 9th harmonic is at 900MHz only 34dB below the fundamental at 100MHz.
To validate the performance of the SA612 I soldered two wires to output of the REF mixer and observed the output using a balanced USB audio input
Second picture shows the 8k audio FFT when the nanoVNA is set to 1MHz. About 100dB SNR at this small audio BW.
The nanoVNA uses less points (48) in its calculations and has therefore substantial less SNR
The third picture shows the output when set to 2GHz. The SNR is reduced to something between 20 and 30dB
This 80dB signal reduction is much larger as the reduction of power in the harmonics but can probably be attributed to the mixing loss in the SA612 as it it operated way out of spec (max 500MHz)
The fourth picture shows the roughly 50dB SNR you get when you operate the nanoVNA at 2GHz from a clean 5V supply. A very welcome improvement making S21 measurements possible.
A quick calculation based on the schematic suggests the REF mixer has the highest signal levels while the TRAN mixer is 10dB lower and REFL is 20dB lower
If I have enough courage I may change the attenuators for the REFL and TRAN mixer to get more balanced power levels.
|
Re: NanoVNA WebApp USB question
On Thu, Oct 17, 2019 at 11:45 AM, QRP RX wrote:
can anyone show the circuit and photo where this 5.1k resistor should be
installed. Is it possible to install it on NanoVNA-H pcb?
Have a look here: You need to attach 5.1K resistors to ground from cc1 and cc2. Scroll up the webpage to see the pins
|
Re: NanoVNA WebApp USB question
can anyone show the circuit and photo where this 5.1k resistor should be installed. Is it possible to install it on NanoVNA-H pcb?
|
Re: Owen Duffy on improvised test fixtures
#test-jig
Martin 5:37am #5091 Martin - G8JNJ wrote: Owen is one I'd always listen to, even if personally challenged by what he has said or written. It's happened to me, I've learnt a lot in the process, and continue to respect him. Ditto for me. After I decided to ignore the irrelevant emotional content, I learned a lot from Owen Duffy.
|
Re: NanoVNA WebApp USB question
Some people said that you can solder anything you see, so get a magnifying glass. "Some people" have never experienced familial palsy.
"Some people" have good depth perception
|
Re: NanoVNA WebApp USB question
From: sala nimi: Some people said that you can solder anything you see, so get a magnifying glass. "Some people" have never experienced familial palsy.
|
Re: Any ideas for test jigs?
I have been using a fixed L and a fixed C on 3.5 and 10 MHz. Works very
well in getting a quick check of calibration.
Mel, K6KBE
<>
Virus-free.
www.avg.com
<>
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
toggle quoted message
Show quoted text
On Thu, Oct 17, 2019 at 7:17 AM Oristo <ormpoa@...> wrote: Perhaps a 500 ohms reactance would work in measuring. Perhaps calibrating nanoVNA THRU using an RF Active Probe, e.g.
|
N0YWB
gin&pez@arg
Oristo
