As a low-level, VFR pilot, I only pick them up if I am above any hills or mountains, and only pick up the one I am tuned into on my Nav1 radio.
I can have a VOR/DME station right in front of me, and if I am behind a hill, at low level, I loose the signal....!
Cheers mate...

...!
Paul.
(England).
Win 8.1 64-bit. DX11. Advent Tower. Intel i7-3770 3.9 GHz 8-core. 8 GB System RAM. AMD Radeon HD 7700 1GB RAM. DVD ROM. 2 Terra Byte SATA Hard Drive. Philips 17" LCD Monitor. Saitek Cyborg X Fly-5 Joystick. ...and a Briggs and Stratton Petrol Lawn Mower.