My customer told me that one of the RF pcb need to maintain the 5mils trace width within 5% tolerance in order to achive 50 ohms impedance. My pcb maker said they can only control at 20%(copper etching process capability) trace width tolerance BUT can guarantee that the impedance is at 50 ohms. Please comment.Should I take the words of pcb supplier? rgds sumxp --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 1.8e 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 -----------------------------------------------------