The portable dishes are not omnidirectional; the dish itself is pretty small and can only see 1 of the 2 satellites at a time. They are supposed to be located with the handle pointing north. There's no assurance your rig will be parked in the right direction every time.
I'm planning on buying one of the Flagpole Buddy systems like Daryl in the very near future. Elevation is never a bad thing especially if there are other tall rigs parked next to you and as he mentioned, a tree canopy.
If you have a dual output dish and haven't learned this yet: The coax port on the RIGHT hand side of the dish is output #1. This is important if you plan on connecting 2 TVs; it will default to the channel the receiver connected to #1 is connected to. Remember it can only see 1 satellite at a time, and #1 is the master driver.