Actually having alot of airconds within near proximity to each other in an area which is building dense would have an increase in ambient temperature.

Quite common for botched up wiring jobs to occur. Lots of flats have addition SCV points in multiple rooms. If the splitter, cabling and end points are not up to par, then the signal degrades as well.

I recently put a TV in a spare bedroom with no SCV point, so I used a 15m long thin-gauge flexible coaxial cable to connect that TV to the SCV splitter point in the living room (slipping the cable under the bedroom door). Nothing more than a simple screw male-female connection but the degradation in signal quality is noticeable. When I connect the TV using the short, very stiff coax cable from Starhub, the picture looks noticeably better.