Well, did try replacement, 80cm solid dish with no percievable improvement.
By chance, noticed that waving arm across dish face did not affect received signal. Then tried progressively screening dish face (with some folded cardboard) working from bottom edge upwards, signal level remained unaffected until top edge of cardboard screen reached centre of dish, then signal degraded dramatically. Doh !!!!!!!!
I had been sure that dish was looking at clear horizon but this test suggested that the bottom half of dish was in a signal shadow area. The roof ridge of the house across the road and about 50 metres away was too low to be causing a problem but then maybe the dish was actually lining up with part of the house chimney!
I decided that lifting the dish by at least 60 cm should take it out of shadow. The 24" length pf pole was replaced by a 48" and the dish remounted to above the top bracket of the TK pair. What a difference, sorted. Reception now ok for last two weeks.
Moral, check and check again. Ta for reading |