ALC has a higher gain 5dbi antenna that is compatible with all ALC Observer cameras.  This longer antenna will boost the signal from the camera to the monitor.  The antenna part number is ANT5DB.

https://www.alcwireless.com/product/ant5db/

We also have a 10 ft cable (CAB10F) that gives you the flexibility to move the antenna away from the camera and allow you to position the antenna in a better location to have a stronger signal to your monitor.  This cable works in conjunction with the 5dbi antenna.  This works especially well with metal buildings.  It allows you to position the antenna near a window or actually inside the building where the monitor is located.

https://www.alcwireless.com/product/cab10f-antenna-extension-cable/