Neo coolcam ds01z sensor with external antenna

Hi all,

I have a neo coolcam ds01z doorsensor, which I want to use as a mail detector in my mailbox. The problem is, that the mailbox is a metal box so no signal are reaching my homey.

My idea is to connect a external antenna to the device outside the mailbox. But I don’t know where to connect it to the sensor.

has Anyone done this before and can put a picture of it here that can help me? or is there a easier way to do this?

I adjusted the doorsensor at the point where the mailbox opens. That wat it works great. I also added a motionsensor from Neo Coolcom inside the box. As soon there is mail, motion will Be detected. The distance is a problem, try to have a repeater in short distance.