Free images results:

Signal pictures, stock photos and images


Off Royalty Free Stock Image
Author: Litllady25
Thumbs up Stock Photos
Author: Prawny
Pager Stock Image
Author: Xmasbaby
Sunset Stock Photo
Author: Birdy_62
Bell Stock Images
Author: Ichtor
Biker Royalty Free Stock Photo
Author: Chelnok
Falcon Royalty Free Stock Photos
Author: Pamelajane
Car_8 Royalty Free Stock Photography
Author: Clv69
Car_5 Stock Photos
Author: Clv69
Car_10 Stock Images
Author: Clv69

Also, here are some commercial RF-licensed images that match your search criteria:  
Signal Royalty Free Stock Photo
Author: Lookatmy

Explore more commercial options: More Signal Stock Illustrations & Vectors | More Signal Stock Video Footage