Losing channels overnight

[Stainl988]

Box:

Manufacturer: Sagemcom

Model: RTIW387

Variant: RTIW387.002.P

Hardware Version: 0007

Software:

Component Software: 4.2.226(6eac6b)

Manufacturer Software: 0.14.56

Broadband connection is wired.

My eetv box keeps losing channels overnight, even after factory reset. Initially,  I had 175 channels. All seem to be 100% signal quality, an example being channels 102.

Each morning, I have either 74 or 26 channels left. Channel 102 is one of those missing. If I retune or factory reset, the channels return. They seem to be lost again overnight. All cables seem to be connected correctly and given the channels always show as 100% without fiddling with these, it seems to be a box issue. I am not sure how to proceed. 

[DarrenDev]

Is anything being turned off overnight that could be affecting the aerial?  e.g. a signal booster?  Or is the aerial passing through any equipment on its way to your TV Box, that is being turned off?

Also, it's worth checking signal strength - if this is also 100%, then the signal is actually too STRONG for the box. An attenuator would fix this.