We’ve had a bit of a mystery unfolding on our network over the last couple of days. Early Wednesday morning, multiple WombatNET access points across the Wellington region—including areas deep in the Hutt Valley—started flapping, with DFS (Dynamic Frequency Selection) events firing off across the board.
At first, we assumed it was just the severe weather. Rain can cause signal reflections and propagation anomalies that mess with 5 GHz links. But this time, something didn’t add up. The scale, the timing, and the pattern all pointed to something bigger.
As it turns out, we weren’t the only ones affected. Providers across the country—Primo in Taranaki, Inspire Net in the Manawatū, and TPNet in Nelson—all reported sudden, widespread DFS interference starting around 2 AM. And the common denominator? A radar sweep from the Australian Navy’s HMAS Canberra, passing down the west coast of Aotearoa.
DFS is a safety mechanism built into 5 GHz wireless systems. It requires access points to automatically switch channels if radar signals (like those used by aircraft, weather stations, or military vessels) are detected. In this case, the warship’s radar triggered DFS events across wide swathes of New Zealand, temporarily knocking wireless broadband links offline as the systems scrambled to find clear channels.
It’s rare—this level of interference hasn’t been seen in years, and never at this scale. The fact that even WombatNET access points nestled in sheltered valleys like Upper Hutt were affected shows just how powerful these radar sweeps are. Even some of our links using directional antennas and frequency tuning weren’t immune.
If you noticed short dropouts or degraded speeds, this was likely the cause. We’ve systematically rechecked and adjusted frequencies to ensure everything’s back to normal.
Events like this also highlight the need for better spectrum availability for WISPs. The 5 GHz band we use is shared with radar systems, and that’s why we need action on opening up the 6 GHz band in New Zealand—a step that could help avoid future incidents like this.
As always, if you’re having ongoing issues or something seems off, don’t hesitate to flick us a message. And if you want to nerd out about DFS, spectrum, or anything wireless—we’re always keen to talk.
