Hi, My understanding is that VSWR is a voltage standing ratio therefore 1:1 means forward = reverse in terms of power ratio hence the calculation of 1. hope this helps. Would like to see your final code posted and some details on the electronics involved as I would be interested in also making such a device. What power & frequency ranges are you using? -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu