Techniques of antenna cable delay measurement for GPS time transfer We compare the measurement results of antenna cable delay obtained from six different techniques, including some that allow the measurement of the cable installed in-situ. Among these techniques, the reflection of a pulse from the open end of the cable is described and compared with the results obtained with all the other techniques. We obtain a sub-ns consistency between all techniques for three cables of different types, the best technique, based on a Vector Network Analyzer, providing an uncertainty we estimate within 100 ps.