Up until now, I have had my bedroom TV hooded up to a set-top aerial, as this worked very well in the past with the aerial sitting on the Window sill. The glass was double-glazing, but as the seal went on the window, we had it replaced. One thing I noticed about the replacement was that it had a sticker on it saying "Low 'E' coated with argon gas".
After the glass was replaced, I put the TV top aerial back on the sill where it was, but when I turned on the TV, I got absolutely no picture! I checked the aerial and it was plugged in and checked another TV connected to the loft aerial and its picture was fine.
So I moved my set-top aerial around and to my surprise, if I placed the aerial anywhere in front of the window, I had not even the faintest image on any analogue channel, never mind a DVB-T channel, including RTÃ‰ 1 which use to come in perfect. However, if I moved the aerial away from the Window, I would get a picture, albeit a weak picture due to the concrete wall attenuating the signal:
Aerial in front of low 'E' coated window in left iamge and moved away in the right image.
I figured I would mention here in case anyone else had problems with a TV-top aerial, that it may be the Window blocking the signal and not a fault with the aerial.