A recent visit from the Australian Navy’s largest ship, HMAS Canberra, resulted in an unexpected and widespread disruption to New Zealand’s internet and radio services. The incident, which occurred on June 4th, left many New Zealanders offline and baffled.

Matthew Harrison, the head of New Zealand ISP Primo, described the event as unprecedented. In a LinkedIn post, he explained that the outage began around 2 a.m., affecting numerous 5 GHz wireless networks along the Taranaki coastline. The culprit? The HMAS Canberra’s radar system.

According to Harrison, the ship’s radar, utilizing Dynamic Frequency Selection (DFS), caused a cascade of failures as it swept across the area. This unexpected interference overwhelmed the 5 GHz access points, knocking them offline and creating significant disruption to Primo’s network.

This incident highlights the potential for unexpected interference from powerful radar systems on civilian wireless networks. The sheer scale of the outage serves as a reminder of the interconnectedness of our digital infrastructure and its vulnerability to unforeseen circumstances. While friendly relations between Australia and New Zealand remain strong, this certainly made for a memorable (and inconvenient) visit from the HMAS Canberra.