Sam Wilson writes:

This is probably a bad idea since I know almost nothing about how radio
waves propagate at sat-TV frequencies,

Pretty much straight line, I think. Otherwise the airport surveillance
radars which show ATC/S where on the taxiways planes are on a foggy day
or after dark wouldn't be much use.
(I think that's called X band , or some such, running at frequencies
vaguely similar to satellite Ku band.)

but is there any chance of
getting a reflection of something at the other side or at the end of the
block?

Quite probably, but AIUI the direct signal is already very weak, having
travelled 22,400 miles.
I'm sure one could use a reflection if one used a 30 foot dish, say,
but......

I also assume you're not on the ground floor since you would
already have thought about mounting the dish on the ground away from the
wall, right?

One floor up.

I'm pondering where best to put the dish so the protruding [ shaped
attachment to the neighbouring drainpipe doesn't get in the way. But I
don't know the elevation above our horizontal of synchronous satellites
at our latitude.
About 30 degrees, I'm guessing. Obviously I will learn this along the
way!

--
Windmill, Use t m i l l
@ O n e t e l
. c o m