[SI-LIST] Re: VNA Calibration for COAX Testing

Hi,
        The VSWR seems ok. We DON'T have TDR machine, but
the VNA has a VSWR button to convert S11. We just got a
new calibration kit for the DIN1.0/2.3 connectors, doesn't
include a "THRU" standard. I'm not even sure it would be=20
available for the 3.5 to DIN1.0/2.3 on each end, respectivly.
        In the VNA Manual the speak of fabrication of "THRU"
standards for TRM measurements. The manual says that a 1/4
wavelength line should be an approximate phase shift of 90
degrees. Which would be optimal to avoid resonant points of
0 or 180 degrees.=20
                        Electrical Length (cm) =3D (LINE - o length Thru)

        Electrical Length (cm) =3D (LINE x Velocity Factor)/ Delta f

This equation doesn't allow for a 20M to 2.2GHz Through standard=20
to be more that a VERY small length.=20
        The standards of the VNA can be adjusted by changing the
delay in the thru standards in the cal kit menus. However, this
seems a little extreme.=20
        Could I use an adapter as a "THRU"? What kind of error would
you expect to see?

-----Original Message-----
From: Clewell, Craig [mailto:cclewell@xxxxxxxxxxxxxx]
Sent: Wednesday, April 23, 2003 9:54 AM
To: Moeller, Merrick
Subject: RE: [SI-LIST] VNA Calibration for COAX Testing


Hi Merrick,=20

If you get the VSWR measurement (basically and S11 measurement) you have =
the
TDR data.  All you have to do is transform the data.  Now that process =
is a
bit more entailed then I am making it sound, but what you need to do is
perform and IFFT on the S11 data.

As far as the standard goes...I wouldn't "create" a through for the
calibration.  I would buy a new kit.  It is very important to have the
correct standards when performing the calibration.   There are 12 error
terms that you correct for during the calibration process.  The more of
these you don't account for the less accurate your measurements will be.
You may even get non-causal data due to lack of a good calibration.   I
would ask Dave to spring for a new cal kit.

Hope things are going well,=20

Craig


-----Original Message-----
From: Moeller, Merrick [mailto:mmoeller@xxxxxxxxxxxxxxx]
Sent: Wednesday, April 23, 2003 9:51 AM
To: Si-List (E-mail)
Subject: [SI-LIST] VNA Calibration for COAX Testing


Hi. I have a two port VNA and want to perfrom some VSWR and
Attenuation measurement on a 10' cable assembly. SMA on one=20
end and DIN 1.0/2.3 on the other. I need to perform a two port =
calibration.
I have an SMA Calibration kit, as well as a DIN 1.0/2.3 Kit. However, I
don't have a "THRU" standard. What would be a reliable way to create
such a standard???

Second, Is there a simple technique for getting characteristic impedance
from a measurement setup of this type?

Regards,
Merrick M. Moeller
Design Engineer Electrical
Cinch Connectors INC.
1700 Finely Rd
Lombard IL, 60148
Phone: 630-693-2062
Fax: 630-7056058
mmoeller@xxxxxxxxx


------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List archives are viewable at:    =20
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages=20
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu
 =20
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages 
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

Other related posts: