Call the police is the only solution. It might not solve the homeless problem but very effective for moving it out of your backyard.In my experience the police can always find a reason, legitimate or less legitimate, to get rid of them.
Sometimes it can create some ridiculous situations though. I very briefly lived in the city of Humboldt and experienced something like this. As all cities in California, it has a problem with the homeless. To deal with this problem the town had passed an ordinance where it a person could not "loiter" in the same location within city limits for longer than two hours. The homeless would then have to move to another spot every few hours and then on etc.
It made the downtown this bizarre mix of musical chairs and a clock where you could often tell the time of day by what homeless people were in front of what building.

suppressors are badass but i don't have firearms license so its a no go.
Did I mention I recently bought an LMT Defender 2000? I probably did...proud of that one. Depending on my bonus this year i've been considering buying one of my pops old SCARs. Faggot doesn't need three of them.
Pipe weapons are the tits.