Please read bellow after GUS: Hi Experts, I am just starting / trying to do high speed measurements with pico probes and would like to get some feedback how to do it right. I have GGB model 40A pico probes, a GGB CS-11 calibration substrate and Quater research XYZ500 micropositioners. GUS: Not familiar with the XYZ500 positioners, have a different one, but have used CS-11 and GGB 40A probes. What's the recommended magnification for the microscope to place the probes? GUS: Not entirely sure I understand your question, or maybe your setup, but you just need to make sure you clearly see your landing. Most of the times it's easier just looking on the u-scope directly, (not digitally on a monitor) since there is a much better 3D feel and you'll be able to see depth better. How do I know, when the probe tip touches the calibration substrate or the DUT GUS: Some VNAs during calibration will forced you to a particular view, this is my case when doing guided-cal, (magnitude only visible), If this is your situation I would recommend land the probes first on the CS-11 50Ohms load, then you'll clearly see when the probe is landed (you should see a low and slowly increasing return loss). You can't see this, when looking at magnitude on a short or open. After you set the angle position of your probe on the 50 Ohms you are much more likely to get a good landing on the short and open using the same probe angle. If your VNA allows you to view two channels simultaneously when calibrating in one of them, you can set the un-calibrated channel to view the phase. With that, now you'll see the phase change by 180degrees on a short. On the open, you can put a pointer on the phase on the un-calibrated channel and you'll see the angle change bit, not much, but at least is some indication. GUS: Summary. If your VNA allow viewing only one channel during cal: - Set the channel to magnitude - Land first on the 50Ohms and make sure the contact is good with not to much pressure - Then proceed with the cal. If your VNA allows to view two channels simultaneously: - Follow the above list + - Set the additional channel to view phase. How far do I overdrive to get good contact of teh probe to the calibration substrate or DUT GUS: Here, you'll need some practice. If you are using the probes that are pretty long, (S like) then probably you can start by doing this: -Land the probes on the white ceramic area just passing the 50Ohms(for example) - When you see the probes touching the white ceramic piece, push a bit more such the probe slides just a bit on the white part - Bring the probes back towards the 50Ohms cal, you should see a bit of an scratch both on the tip and ground when moving through the gold part. (It's important you bring your probes back to the substrate and never push, because if you do, the probe will jump an the GND blade will start to weaken and deform) - Look at the screen and see if you got a good landing. - If you did, on that position, lift the probe and put it down again, with no much pressure you should have a good landing. - If you did not make good contact, adjust a bit the angle and repeat the procedure from the beginning. For the through on the calibration substrate, how do I control how far I need to go from the edge to the inside, so that I probe the right lenght of the through. GUS: Please review the CS-11 manual, in there they show you a nice picture for the proper through positioning with respect to the edge. GUS: Hope this helps. Any help / feedback is greatly appreciated, Axel Regards Gus ____________________________________________________________________________ ________ Be a better Globetrotter. Get better travel answers from someone who knows. Yahoo! Answers - Check it out. http://answers.yahoo.com/dir/?link=list&sid=396545469 ------------------------------------------------------------------ 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: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.net List archives are viewable at: //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 ------------------------------------------------------------------ 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: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.net List archives are viewable at: //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