The Manchester and Merseyside areas are swamped by signals from Moel y Parc in north Wales, so much so that during Freeview scans, its channels often grab primary EPG
positions. If Winter Hill does fail, many will probably receive a usable service from MyP off the back of their aerials
Not neccessarily, for most of Manchester Moel y Parc is in the totally opposite direction to Winter Hill, putting it in the direction TV aerials are designed to reject. Until recently I lived in the Salford Quays area for a few years, and my TV would barely register a signal from Moel y Parc. Usually it would pick up that a couple of muxes existed, but would struggle to decode anything more than service names, and would put them in the 800's in a barely usable state. It was only on rare occasions where there were lift conditions that the services became watchable.
Not sure why they said that. National FM radio services, and BBC Radio Manchester come from Holme Moss, and Key 103 is from Saddleworth. DAB services are present from a multitude of other sites, and quite honestly the other radio services from Winter Hill are candy floss stuff
Heart, Smooth and Rock FM come from only Winter Hill, so they would have been affected, and they are major services with high listenership. Although the DAB services do have other sites, especially from City Tower in Manchester, a large part of the area is served by only Winter Hill so it would have had quite an affect.
Although the impact on BBC national radio would have been limited, as Holme Moss and other sites further north would have still been in action, reception can be patch in many areas, including in Manchester itself. I know I always had better coverage on Winter Hill's frequency rather than Holme Moss's, which was affected by the terrain and multipath from the buildings. It also wouldn't surprise me if Winter Hill formed part of the microwave distribution network, so an issue there has the potential to affect services further north.
As you say the Manchester local services would have been unaffected as they come from City Tower, or in Hits Radio's (new name for Key 103) case, Saddleworth.