You could contact the guys at Introbotics. www.Introbotics.com They had a huge part in the writing of the 2.5.5.7 document and are extremely knowledgeable on the subject. For field solvers, Polar is probably the most common and popular. There's also Apsim Technology (my preference), but the UI is coarse. In a former life, I was a Process Engineer for a Controlled Impedance Test department. If you'd like, give me a call and I'll see if I can answer any questions for you. Regards, Craig Sullivan Manufacturing Engineer MPL Incorporated P: 607.266.0480 F: 607.266.0482 <mailto:[log in to unmask]> <http://www.mplinc.com/> -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Louis Hart Sent: Thursday, June 26, 2008 7:22 PM To: [log in to unmask] Subject: [TN] controlled impedance TechNetters, can anyone assist me with understanding controlled impedance measurements on unpopulated PCBs? I have looked at TM-650, method 2.5.5.7. If anyone with experience in making controlled impedance measurements could contact me, I would appreciate it greatly. Louis Louis Hart Compunetics Monroeville, PA USA [log in to unmask]<mailto:[log in to unmask]> 412-858-1272 --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest Search the archives of previous posts at: http://listserv.ipc.org/archives Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------