Originally Posted by chrisjr:
“Sometimes if the aerial cable is wrapped up with other cables, such as HDMI leads it can pick up unwanted interference so untangling it or simply moving it away from other cables can often be beneficial.”
Originally Posted by gomezz:
“Or a stray strand of shielding braid was shorting out the signal in the plug.”
Both above are valid reasons.
It's useful to know that HDMI cables and the TX/RX circuits in devices emit interference at specific frequencies that match up to some of the UHF frequencies used for Freeview. If your local Freeview transmitter is broadcasting on those same frequencies then either poorly shielded HDMI- or aerial coax fly leads (or both) can result in a loss of those signals at the matching frequencies of the mux. The frequencies of the various muxes vary by transmitter. This makes it harder to predict the behaviour.
There's a couple of things that can be done to help reduce the likelihood of these issues. The simplest and easiest is to ditch any freebie/cheap aerial coax cables and flyleads that look like
this or similar. Those cables either free or sold in DIY and electrical stores and supermarkets are just awful quality. Ditch 'em. Buy a bit of WF100 coax and add some plugs. Your TV will love you for it thanks to the extra shielding.
The second thing is harder; it's finding well shielded HDMI cables. Unfortunately it's really difficult to tell good from bad on HDMI cables other than by thickness. Even then, there's no guarantee that thicker HDMI cables haven't just been bulked out with cheap filling material rather than effective shielding.
There's one other reasonably common cause of specific channel loss that's often overlooked. It's crushed or bent aerial coax.
