I have a few busted sprinkler heads so I decided to dig a trench along the
line and examine the line. I was amazed that in a stretch of 60' the pipe
went from 1-1/2" diameter to 3/4" to 1" then back to 3/4" as it goes
downstream. I think over the year sections of pipes were being repalced or
modified.

I assume the changes in the diameters like this would cause unnecessary
pressure loss or even un-uniform pressure for each sprinkler head on that
line? So I am planning to replace them all with a long stretch of pipe with
the same diameter. I am not sure what diameter to use, should I stay with
1-1/2" or reduce it to a smaller diameter? This line runs down the middle
of a side yard about 25' wide and 75 feet long but the run is only 60'. How
far apart should I space the sprinkler heads if I used 360 degree heads?

Another question is at the end of that 60' run is a big tree occupying the
end of that yard, and the root system is such that I cannot trench any
further. I am wondering if it's ok (will there be enough pressure) to put a
big 360 degree impact rotor sprinkler head on the end of the pipe run to try
to cover the area of the tree, but I don't know if it's going to have enough
pressure to run that rotor sprinkler at the end of the line. How can I
determine that without actually gluing up everything to try it?

Thanks,

MC