I used to work in metrology/calibration labs. Some of the microwave equipment we calibrated had test procedures that had an SWR spec. However, since SWR reading depends on the position of the SWR meter in the transmission line, SWR measurement was considered to be more metaphysics than metrology. - R. L. Measures, a.k.a. Rich..., 805.386.3734,AG6K, www.vcnet.com/measures. end