This is an antenna mount that I designed. It can also be used as a shelf for a battery or altimeter. I designed it for my specific need but hope it helps out others. It mounts under the landing gear and raises the phatom up 4mm. You will need longer screws to mount this.

I printed this with 100% infill so I could tighten down the sma connector tight. I used my screws from my prop guards to replaced the stock screws and they worked great.