than this, placing them well away from the Earth and hence effectively rule out sources of local origin.

The discovery observations containing the FRBs were carefully inspected to check for similar events at the same time and with the same DM as the FRB, in other fan-beams. No other broadband pulses were detected in any other fan-beams within approximately 60 seconds of the bursts. Moreover, in addition to all the tied array fan-beams, we form a single special fan-beam as the incoherent sum of all the other fan-beams. This “total power” fan-beam was also searched for events near the UTC of the 3 bursts. For the 3 FRBs, this fan-beam contained no unusual sources of RFI. Only twice during the 3 surveys did we find FRB-like candidates (i.e. appearing across the band) which were identified as RFI upon closer analysis. In each case, similar events could be found in dozens to hundreds of fan beams, and were thus obvious near-field RFI. These false candidates also had ‘patchy’ power across the observing band, indicative of RFI generated from different carrier handsets operating at the same time in our band.

![Simulations of the detections of FRB 160317 in adjacent fan-beams (FB) to 