Speed camera vans utilise the K Band frequency – check K Band is enabled in your radar.  It may also be your radar detector is just out of date and old technology.

NZ Police Speed Camera Van

A parked speed camera van

Unfortunately, the radar inside the speed camera van runs with a very low power radar and is usually focussed pointing across to the opposite side of the road, not along the road in the direction of traffic flow.  This means the radar detector has to be nearly beside the speed camera van before it picks up the signal.

The radar systems in patrol cars are pointing in the direction of oncoming traffic (or traffic following behind).  This is much easier to detect compared to a mobile speed camera set up inside a van on the side of the road, simply because the technology is totally different.

There is really no simple solution for this, other than driving slower or upgrading to the fully installed Stinger radar detector system.

Read more about Stinger radar at Stinger.co.nz.