I have searched everywhere but cannot find any reference to this.
I was out at YMML earlier this week sitting under the approach to RWY16, and noticed some new infrastructure on the airport perimeter. There are 32 strange looking black objects lined up horizontal to and directly under the approach, which make a strange upward inflecting siren that goes about 5 times every time a jet goes over them (did not make sound for the smaller, slower props).
The only way I can describe their appearance is that they look like plant-pots that were designed by the same people that built the F117 Nighthawk
Are these anything to do with the CatIII upgrade that they are looking at for YMML?