The SCATX is designed especially for Police band, Airband, Ambulance & Fire brigade scanning, and in some cases can also be used as a transmitting antenna on the following frequencies 468MHz 4.5dBi gain, 124MHz 2dBi gain, 73MHz unity gain and 40MHz 1/4 wave, the SCATX is resonant at these frequencies with a SWR < 1.5:1. Note. Requires UHF Base. Not to be used with accessories like a spring or quick disconnect base, etc. Antenna can be mounting under a gutter upside down