DONT install a 1.5m dish on a chimney no matter how solid it looks!!
The forces exerted by gale force winds are enormous and the chimney will fail sooner or later.
Well, six months later and I have taken advantage of the fact that our building community decided to renew the roof. I arranged (and got permission) to have a concrete base made and a 70 mm mast installed on it (ordered from TDT professional down in Malaga) by the builders. I had intended to wait and see what happens with the 2E satellite before upgrading my 100 cm dish but as hauling a big satellite dish onto the roof of a five-storey building is not for the faint hearted, I went ahead and ordered a Gibertini OP150 and the guys working on the roof gave me a hand installing it (i.e. they held it in place while I screwed it to the mounting). Initial results were disappointing until I realised the LNB arm was upside down. Put that right and went downstairs to see if I could get Channel five and C4HD and all looked good at around 7 pm. Tried again around 8.15 pm and got 'bad or no signal' on the FOXSAT HDR. 'Mi gozo en un pozo' as they say around here.
Tweaking things didn't seem to make any difference so last week I ordered a Raven Feedhorn and a Invacrom single C120 flange LNB combination from SatelliteSupertore which arrived yesterday and was duly installed. Initial results continued to be disappointing in that signal strength and quality seemed to drop of a cliff at 20.00 as before and in reality performance didn't seem much better than with the IBU I'd been using.
However, I thought I'd go up again today and have another fiddle around and move the feedhorn as far back away from the dish as the possible in the holder (I read about this somewhere). Just now at 7.00 pm the humax gives me 80% strength and 90% quality (occasionally 100%) on both horzontal and vertical frequencies (Five and C4HD - Freesat 105 and 126) - I've never seen more thaN 60% quality before, and it's overcast today and very humid.
7.40 pm now and we're down to 75/80 strength and 80% quality .... 7.45 pm and Five (Horizontal) maintains 80/80% but C4HD is looking a bit flakey with quality dropping to 70% occasionally (I reckon 45% quality is enough for a lock so will these channels be watchable this evening?)
It's now 8.05 pm and all good and strength and quality are maintained when normally at this time the FOXSAT doesn't even register a signal. Maybe it's just coincidence (a good 2F day?) but I'm excited enough to post this right now. It seems that dish size makes the difference but with big dishes a feedhorn C120 LNB combination can also be an important factor in order to get the most out of the dish. Ironically when I changed the position of the feedhorn I didn't even bother to check it with the Satlook metre.