Will a Dish work4 this?

Will a dish antenna with good range generally offer any improvement
where their is no clear line of sight (trees mostly) and may be one
small area that has throughput signal? Already tried a home made
parabola, am getting a connection,but only intermittently and has to be
pointed just right to get that. Can a small dish antenna be aimed
manually-is that possible-the supplier suggests using a monitor to aim
it. This is to a free signal but I have no control over the transmitter.