This is a bog-standard 18-element TV aerial from Wilkinsons (£8.99)
and I plan to mount it in the loft space, where even a room aerial
gives excellent reception via the SLx6 Philex aerial booster.

From my bedroom window I can observe the aerial on the chimney of a
neighbouring house. How can I preserve its "angle" as closely as
possible when I mount my aerial? Or isn't the position that critical?

I've been thinking of schooldays when we were given the trigometric
task of working out a tree's height, but I can't think of any
comparable algorithm to transfer the neighbour's aerial's "direction"
to mine. I'll just have to "remember" the position as I climb into my
loft.

MM