Spin Doctor for indoor or outdoor use. The HELICAL antenna is a passive circular polarized directional wide-band UHF antenna which can be used as a transmitting or receiving antenna for wireless microphones and in-ear monitoring systems. It operates in a frequency range from 470 to 740 MHz and provides an antenna gain of 9dB.This circular polarized HELICAL antenna is specially designed for tour sound, sports and broadcast applications where long range FOH positions of many hundreds of feet often require a high gain. With the included universal threat adapter it can be mounted on floor stands with both 3/8" or 5/8" screws. The HELICAL antenna comes with a durable, water resistant nylon cover which also helps to compress the antenna to easily fit inside a rack drawer.