Hearing range 60 decibels, the hearing range for the Senegal bushbaby is 92 Hz–65 kHz, and 67 Hz–58 kHz for the ring-tailed lemur. Of 19 primates tested, the Japanese macaque had the widest range, 28 Hz–34.5 kHz, compared with 31 Hz–17.6 kHz for humans. Cats have excellent hearing and can detect an extremely broad range of frequencies. They can hear higher-pitched sounds than humans or most dogs, detecting frequencies from 55 Hz up to 79 kHz. Cats do not use this ability to hear ultrasound for communication but it is probably important in hunting, since many species of rodents make ultrasonic calls.
History of broadcasting in Australia there is just a small change in format. 1920s all broadcast services allocated to a few specific frequencies, MF + LF early 1920s Class A Services low end of AM band & longwave, Class B services upper end of band, Amateurs above 1400? kHz mid 1920s AWA-influenced longwave services commenced to be switched off due to difficulties in achieving radiator efficiency late 1920s Australia commences to allocate AM radio services in the range between 1400 kHz and 1500 kHz 1926 AM restack 1930 Captain Eckersley and Radio Research Board give consideration to widespread deployment of longwave services, but eventually it