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.
Charles Samuel Franklin from this site in 1936. Franklin received the 1922 IRE Morris N. Liebmann Memorial Award "for his investigations of short wave directional transmission and reception". Franklin received British patent 242342 in 1924 for "a pronounced directional effect from aerials of the type that are electrically long in comparison with the signal wavelength". Alas, this antenna is so physically tall (about 1,813 feet at 540 kHz, and about 612 feet at 1600 kHz) that its use is generally restricted to frequencies of 1400 kHz and above, with one example at 1500 kHz (KSTP, St. Paul, MN, non-directional, daytime only) and two