FM Omnidirectional HD Stereo Reception Antenna This horizontal FM antenna gives great results if you want to pick up FM radio stations from all directions whether mounted inside or outside. You'll be pleased with the size of this omnidirectional FM antenna as it is big enough to pull in distant FM signals but small enough to mount inside or stealthily outside at 21' diameter. Built to last for years outside but small enough to bring inside. You'll be able to pick up distant FM signals in your attic or crawl space like you never have before. The folded dipole is the most popular FM omnidirectional design in Europe and is a proven performer. This FM antenna is extremely well-built; you will be pleased with the construction quality allowing years of great FM reception.