Has anyone got a 64-bit version of the T-check software from Rohde & Schwarz ?
http://www.rohde-schwarz.cz/file_5737/1ez43_0e.pdf
It describes a way of checking the calibration of a VNA using a T-junction. I was not aware of this method until I read the R&S application note. It appears if you have a lossless 3-port network, with port 3 terminated in a load with some resistance, there's a relationship between the four S-paramters S11, S12, S21 and S22, which can be used to verify the calibration of a VNA. Apparently all one needs is a .s2p Touchstone file and this T-check software.
The trouble is, I can't find T-Check on the Rohde & Schwarz web site. The nearest I got to getting a copy of this program is an amateur radio site
http://www.hamcom.dk/VNWA-E.html
aimed at the low cost VNAs from SRD-kits http://www.sdr-kits.net/ That has a copy of the program, but it will not run on my 64-bit Windows 7 machine. I'm just in the process of setting up a 32-bit XP virtual machine with VirtualBox, with the aim of runing the program on that, but it is a bit of a pain to have to use a virtual machine.
Dave
I think I might know the answer to why this is not on the Rohde & Schwarz web site. Apparently the person who has it at http://www.hamcom.dk/VNWA-E.html states he has permission from Rohde & Schwarz to distribute this for non-commerical purposes. This strikes me as a bit odd, given:
- The Rohde & Schwarz application note says the T-check software is freeware.
- The algorithm is published.
- It's not exactly rocket-science to implement this algorithm from scratch. I reckon I can do it in <500 lines of C code, probably < 50 lines if I used Mathematica.
- Rohde & Schwarz are not exactly aiming their VNAs at non-commercial users. Perhaps Rohde & Schwarz are not over keen on commerical users of Agilent VNAs using Rohde & Schwarz software, but given the simplicity of the algorithm, I don't see why they should care.
Dave
I tell you what I did since I got the 64bit version of Windows. I gave up searching for compatible software and drivers and I put on a separate partition of my hard drive a 32bit version of Windows XP. That will fix all the problems.
Another option is to create a virtual machine in VirtualBox with XP. That is OK for software which is not too processor hungry, and does not need great graphics performance. It would be OK to run this T-check software, but I realized that actually building the algorithm into my software which dumps data from the VNA would be better. There is then no need to save a .s2p file in one bit of software, then read it back in on another.
The advantage of the virtual machine is you don't need to reboot the computer.
On my Sun workstation, which has a quad core 3.33 Xeon and 24 GB RAM, I run some pretty large applications in virtual machines. I have virtual machines running 32-bit XP, 64-bit XP and 64-bit Windows 7. Often several virtual machines are running at the same time, but it would not be practical to do that on a laptop!
Dave
Dave
Myself I would prefer to spend a minute or two rebooting the computer instead using a virtual machine application, which I used in the past and gave me a lot of headache, sometimes slowing the computer to a level of an old i486 processor