Before revision: It used wing and tail-mounted dipole antennae and was sensitive to the mid-VHF band frequencies of 170-220 MHz, subharmonics of the Monica radar's 300 MHz transmissions.
After revision: It used wing and tail-mounted dipole antennae and was sensitive to the mid-VHF band frequencies of 170–220 MHz, subharmonics of the Monica radar's 300 MHz transmissions.