After giving particulars of the equipment and essential data for the French telecommunication-satellite station at Pleumeur-Bodou, the author gives a description of some of the principal results obtained during tests with Telstar I.Acquisition conditions were always excellent, and tracking proved to be very accurate, thus ensuring continuity of the telecommunication link.The experiments comprised joint tests, with one-way and two-way links, and technical tests. The results of the latter, described in the paper, were concerned with finding received-signal power, noise power at radio frequencies, thermal noise generated in the transmission channel, and distortion.