My ITV/C4 Freeview channels have disappeared - what can I do? Is it my SCART ca
It is a feature of television signals that they can be effected by the weather. Aside from the obvious damaged that can be caused by wind or torrential rain, the onset of summer can cause a more intriguing problem called "inversion".
Basically, when the sun heats up the land, the hot air can get trapped below cold air at high level. This creates an "inversion layer" which acts like a polished mirror to TV signals. This causes two problems: you can receive both the original and a reflected signal from your own transmitter (on analogue TV this appears as "ghosting") or interference from TV transmitters that are normally too far distant.
The ITV/C4 multiplex of channels (ITV-1, ITV-2, ITV-3, ITV-4, CITV, C4, More4, E4, Quizcall) use a transmission "mode" called 64QAM, and it is sadly much more prone to these problems.
So, whilst a loft-mounted aerial will provide reception at some time, it will fail at others. The only real solution is to mount the aerial (or a new Class I aerial) outside on a pole, but some people report that changing the cable from the aerial to the set-top box to the high-grade satellite cable can also help.
The SCART connection, by the way, only carries a single TV picture, not the Freeview transmission multiplexes, so if this is disconnected it will result in degradation to every channel at once.
Without knowing which transmitter you are receiving and a full postcode to see predicted reception at your location, it's not possible to say what the problem may be.
I suggest you check your internal coax plugs and connections, flyleads etc., by unplugging them checking for corrosion, poor connections etc, and plugging them in again. If there've been any poor connections simply unplugging and plugging in again helps clean the contacts.
Also check your aerial hasn't moved or been damaged in any high winds and coax is undamaged. Water ingress can affect reception.
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