The theory for the generation of broadband electrostatic noise (BEN) by plasma instabilities of energetic ion beams that exist in the plasma sheet boundary layer (PSBL) predicts two characteristic signatures in the wave data for BEN. These signatures are a gradual rise in the upper frequency of BEN as the spacecraft approaches the plasma boundary layer, and a very rapid rise in the upper frequency near the crossing into the plasma sheet boundary layer from the lobe. Wave data from the 1978 ISEE 1 mission are investigated during approaches and crossings for these two signatures. Several examples of crossings are presented that exhibit both signatures similar to that predicted by the theory. A case of crossing is shown in which the gradual frequency rise signature is absent but the rapid rise is present. This exhibits BEN in the range expected for the low-frequency ion-ion two-stream and the high-frequency Buneman instability. The intermediate frequencies are less intense, which may arise because the intermediate frequency beam-acoustic instability is close to stability (a warm beam temperature can quench it), as is the electron acoustic instability that can occur for warmer ion beams. An example is also given that was detected in a 1980 entry into the PSBL. ¿ American Geophysical Union 1989