Stupid TV antenna / dish installations

This is something I've noticed a lot in recent years and there seems to be a lot of them on the new build estate where I live.  I notice a lot of sky dishes which are installed awkwardly pointing straight "through" the apex of the roof, instead of simply being put on the other side of the house with a clear line of sight to the satellite.   Presumably these installations work otherwise they would have been changed by now.   But with the high frequency of satellite TV being so directional, I'd be surprised if there are never any issues when the roofs are wet.   If I lived in a house and ordered Sky, I would never accept such a dish installation.   

I live in a flat and we have a communal dish and terrestrial antenna.  The dish is on the South side of the building and points through a narrow gap in roofs and always has a decent enough signal.   The terrestrial antenna however, is also on the south side of the building and points North to the transmitter at Beckley near Oxford.... Alas, not up above the roof apex, but straight through the roof.   Why go to the trouble of putting up an outdoor antenna if you are going to set it up like that?   A loft antenna ought to work better in my view as there is only one half of the roof for the signal to get through.    I have Sky TV but I also have Freeview connected to a TV in the bedroom which I very rarely watch.   I've never noticed if the signal stutters in heavy rain.

I don't understand the reason for what I think are p*ss poor installations.   Why would you place any directional antenna with obstacles in it's way when it could have a perfectly clear line of sight from another position on the building?  Laziness?  Incompetence?   Have you had to have any debates with a Sky installer about dish position?  Obviously it doesn't ruin my life how other people's antennas / dishes are positioned but it's something which perplexes me!

Are you taking into account that the dish isn't flat and it's bowl shape can take signals from a wide range of angles and focus them on the point where the LNB is? Satellite TV isn't just provided from one satellite, it's provided from a constellation of them.

If dishes were like a yagi and had a narrow beam pattern then it would be a problem but they don't. And during installation the installer has to check the signal strength which they can do on the set top box.

Northern Crusader wrote:

Are you taking into account that the dish isn't flat and it's bowl shape can take signals from a wide range of angles and focus them on the point where the LNB is? Satellite TV isn't just provided from one satellite, it's provided from a constellation of them.

If dishes were like a yagi and had a narrow beam pattern then it would be a problem but they don't. And during installation the installer has to check the signal strength which they can do on the set top box.

I realise there are many different Astra satellites up there .   Are you suggesting that the signal to one dish can come from multiple?   It would be interesting to find out what the the reception shape is of an average sky dish is.   I realise there are different dishes for different regions.   I think dishes further North tend to be bigger?

I am very happy to learn more about how dishes work and I'm sure there are plenty of folk like yourself who can help me.   But if you are pointing towards the apex of a roof, surely you are only using part of the dish to collect the signal?

Two main types of Satellite dishes , prime focus - mainly for larger dishes (2m+)that point directly at the satellite and the off set ones that are common for sly in the UK - the dish looks like it is pointing lower than what it is actually receiving the signals from . The channels that make up the sly package come from several satellites some of which are just there as spare capacity and these satellites constantly move in a certain grid area but always with their beam direction covering the UK.

As Bean mentions above, the satellite dish used for sky installations are off set.
 
In short, the dish looks as though it is pointing at the roof but in fact receives a signal at an inclination of approx. 21-27 degrees, the parabolic reflector guides the signal from the various satellites used by sky to the LNB which is normally off set slightly dependant on where in the country you live.
 
With regard to the larger dish point, it is not normally needed now due to the footprint / focussing of the beam directed at the UK / EU, these are now much tighter than many years ago. 
 
Many installers are now forced to install equipment out of sight, i.e on the rear of property due to planning regulations.
 
The link below will explain a little more with regard to signal footprint.
 
https://satfi.co.uk/coverage/
 
Hope this helps a little.

Thanks for the info everyone.   Perhaps some of these dish installations are not so stupid then!   Although I will maintain that I think the terrestrial antenna on the block of flats pointing straight through the roof is daft.

Hi, all of above comments are just about correct, been in the space business manufacture in the UK for forty years.... (must retire some day...)  the Yagi, mine is in the actual roof space, 14 miles from the TX, a bit of tweaking and some RAM behind the reflector to help stop reflections works fine although with digital TX old type ghosting is not a real problem anymore...    and terrestrial signals are totally massive in comparison to a SAT downlink... this helps...ha-ha.  My neighbour has his on the roof but the wrong polarisation and at least 5 degrees off.... good signal though..  a lot is down to the type of antenna, just because it painted gold doesn't help... :-)   Cheers