There are a a few things that can affect how many cameras you can realistically send over a wireless link.
1. The throughput of the wireless bridge
This is the advertised and real network speed achievable through the wireless link. The devices may advertise a throughput of 300 Mbps for example although in reality actual throughput may be less depending on range, line of sight, interference etc.
2. The bandwidth of the cameras
The bandwidth of the cameras is also affected by several factors
- Compression method
- Frame-rate (images per second)
- Image quality
- Complexity of the image
You can use the Hikvision storage and network calculator to calculate the bandwidth your cameras require reasonably accurately.
Once you know the realistic throughput of your wireless link and have calculated the total bandwidth of your cameras and allowed for some overhead to account for variations you should be able to work out how many cameras your wireless point-to-point link can support.
As an example a typical 2.4 GHz wireless point-to-point bridge will advertise a throughput of 150 Mbps. Even at 50% efficiency that still allows for 75 Mbps throughput.
4 x Hikvision 4 Mega-pixel Lite (2560x1440) IP CCTV cameras using H.265 compression set at 15 frames per second with medium scene complexity require only 8 Mbps in total.
So if your wireless link has good line of sight and a good quality connection then even a basic link can support several medium to high resolution IP CCTV cameras.