Here is a kit that allows you to transmit video up to 500′ for wireless monitoring. The Teradek Spark can transmit video signals at 4kp30 or 1080p60/50 via HDMI (10-bit 4:2:2 color sampling). It uses the 5GHz frequency. The transmitter unit can connect to iOS and Android devices.
Each unit has 1/4″-20 and M3 mounting threads to use with a variety of cameras, cages, and rigs. Both have an OELD display to show the status. This kit is ideal for weddings, conferences and live sports. You can find out more here.