Beware of cheap underperforming clones

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Calibration data for the Tindie SAA2 and the Hugen SAA-2 up to 3.8GHz


Kurt Poulsen 2020/10/07 03:00

Hi all

Finally I got the document finished for release. I have found tha up to
3.8GHz provides good result so it now also covers the 9cm HAM band

Link is

http://www.hamcom.dk/SAA-2/Calibration_Tindie_SAA2_and_Hugen_SAA-2.zip

Please try it out and report you findings

Kind regards

Kurt

Kurt Poulsen 2020/10/07 03:00

Hi all

Finally I got the document finished for release. I have found tha up to
3.8GHz provides good result so it now also covers the 9cm HAM band

Link is

http://www.hamcom.dk/SAA-2/Calibration_Tindie_SAA2_and_Hugen_SAA-2.zip

Please try it out and report you findings

Kind regards

Kurt

Jim Lux 2020/10/06 18:13

On 10/6/20 6:00 PM, Kurt Poulsen wrote:
> Hi all
>
> Finally I got the document finished for release. I have found tha up to
> 3.8GHz provides good result so it now also covers the 9cm HAM band
>

Of course, in the US, that band is (partially) going away.
https://docs.fcc.gov/public/attachments/FCC-20-138A1.pdf

Jim Lux 2020/10/06 18:13

On 10/6/20 6:00 PM, Kurt Poulsen wrote:
> Hi all
>
> Finally I got the document finished for release. I have found tha up to
> 3.8GHz provides good result so it now also covers the 9cm HAM band
>

Of course, in the US, that band is (partially) going away.
https://docs.fcc.gov/public/attachments/FCC-20-138A1.pdf

Siegfried Jackstien 2020/10/07 12:38

superb job done

not only that you give us the way how to calibrate but you als explain
the secrets :-)

guessing similar counts for saa2n (only the values change a bit)

greetz sigi dg9bfc

Am 07.10.2020 um 01:00 schrieb Kurt Poulsen:

ihninger 2020/10/12 12:38

Hello Kurt

Thanks for the calibration data.
I have a SAA2-N but use N-SMA cables. My SOLT kit is a "Amphenol Connex Cal standards" (VNWA by DG8SAQ).
Are you able to provide calibration files for QT and -SAVER?

kind regards
Gerald, OE2IGL

Kurt Poulsen 2020/10/13 10:34

Hi Gerald
For the NanoVNA saver the data can be extracted from the documents attached as link. Find the L&C coefficirents for short and open on page 2
Watch out for the delays as NanoVNA-saver uses Offset delay so you must divide the delays for short and open by a factor of two as VNWA uses the two way delay. The Thru delay is OK as it is as one way delay already
For the load the shunt C can not be entered in NnaoVNA-saver and must be exchanged by a negative L value
Female shunt of 50fF must be substituted by -125pH and the male shunt C of 85fF must be substituted by - 212.5pH
See how to convert in the document
http://www.hamcom.dk/VNWA/Some%20basic%20knowledge%20about%20a%20transmission%20line.pdf
For the VNA-QT I can generate some s1p files "one of theses days" when I get time available.
Please note also that the data for Amphenol Connex are 0 to 500MHz. It might still work a bit higher but no guarantee given.
http://www.hamcom.dk/VNWA/Amphenol Connex Cal standards_rev5_page1.pdf
http://www.hamcom.dk/VNWA/Amphenol Connex Cal standards_rev5_page2.pdf
Kind regards
Kurt

Kurt Poulsen 2020/10/13 11:26

Hi Gerald
I have forgotten to mention that the Offset delays being half the VNWA two way delay are positive. Also that both the short open and load delays must be half and positive offset values and the thru delays are as in the documents
I repeat the broken links as this reflector is weird with respect to links with spaces
http://www.hamcom.dk/VNWA/Amphenol%20Connex%20Cal%20standards_rev5_page1.pdf
http://www.hamcom.dk/VNWA/Amphenol%20Connex%20Cal%20standards_rev5_page2.pdf
Kind regards
Kurt

iz1fks 2020/10/18 06:08

Hello Kurt,
I'm testing calibrations with your data.

I have assumed that since I'm using supplied test cable sma(m)-sma(m) to CH0 with the sma(f)-sma(f) adapter installed at the cable end, i have to use the female kit files (even if the supplied kit is male one, due to adapter use). Unfortunately performing a test measurement of the short after applying the calibration, result is not correct (sweep is not close to the short on the smith cart,but change with frequency). Instead it's correct (close to 0 Ohm) if I will use the male kit files, but i don't understand the reason.

regards

Phil

Kurt Poulsen 2020/10/18 15:41

Hi Phil

A very good question, one of my favorite question in fac,t as it describes the most often misunderstanding about calibration and reference planes.

You are doing exactly the calibration the right way, and when so done the two male adaptors of the two test cables are calibrated such that that their reference planes are with same 0 phase and thus no delay in between them. That count for both S11 and S21. When you then connect the female short and for that matter the female open then you are measuring the short or open impedance and delay and thus the short and open turns clockwise in the smith chart when frequency increases.

What you then measure is exactly the content of the short and female s1p file you use for calibration and the SAA-2 is thus told to compensate for that during calibration, so the test cable male adaptors reference plane is the physical measurement plane which measures correctly. The reason why a male calibration is spot on for the short and open positions in the Smith chart is that the short has 0 delay and the open has a delay of something like 1 to 2ps, which you hardly can see in the Smitchart.

Hope this get the understanding pops up as a bright light 😊

Have fun

Kind regards

Kurt

iz1fks 2020/10/18 07:00

Hello Kurt,

if i have well understood, if I want to perform a measure with sma(f-f) adaptor a tthe end of cable on CH0 I have to use male kit cal data. Instead if I want to perform measurement with the test cable ending with its sma(m) connector I have to use the female kit cal data. In other words male or female kit data don't change the pratical way the cal is performed since only male kit open-shot-load and female thru are available, but the reference plane only is affected, is it right?

thanks again

Phil

Kurt Poulsen 2020/10/18 16:39

Hi Phil
Yes it all depends what DUT you want to measure.
If you have a DUT with female adaptors on both the input and output you must use female calibration and then the two SMA male adaptor at the end of the two test cables are in sync with no delay and no loss. During calibration the female female adaptor is so to speak removed electrically.
If you however perform a male calibration at the end of the female female adaptor you must not remove the female female adaptor but leave is at the end of the test cable connected to port1. During the thru calibration there is used a kind of virtual male to female invisible adaptor of 0 length as the SMA male from the test cable on port 2 is connected to the female female adaptor.
Then the calibration is correct for a DUT with male on the input and female on the output but you cannot revert the DUT and measure S21 and S22. In that case you may use a female calibration and use the s2p file for thru calibration from the male kit as it is includes the Virtual 0 length thru adaptor. And after that form of calibration you can measure the reverse direction the right way.
Just removing the female female adaptor after a male calibration destroy the phase and amplitude sync between s11 an s21 calibration due to the female female adaptor delay now till in force .
Kind regards
Kurt

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