Dog poop or a US Air Force rescue beacon?
Invented by the United States military intelligence in the 1970s, below is a T-1151 Dog Doo Transmitter from the collection of the National Museum of the US Air Force that looks gross, but was unbelievably useful during the Vietnam War; this poop transmitter was actually a homing beacon.
As described by the museum, ‘Dropped along the Ho Chi Minh trail by air, this device transmitted a warning when supply movements occurred during the night. The signals were monitored by a variety of agencies, including the CIA.’
A Dod Doo radio transmitter, officially known as a T-1151 radio transmitter, is a radio transmission device camouflaged as a pile of dog shit or any other animal fecal matter. The device was specially designed in this disgusting way to avoid detection or disruption. It was initially used in Vietnam.
Small in size, just four inches long and three-quarters of an inch in height, this tiny spy could be carried easily, sending and receiving radio messages by Morse code. Since the device gave the appearance of fecal matter, it was often left undisturbed and thus had a long battery life making it more efficient as a homing beacon even when planted days or weeks before a mission.
Gale Encyclopedia of Espionage & Intelligence talks about it as:
At just over four inches long and three-quarters of an inch in height, this inconspicuous spy tool was small enough to be carried easily. It could send or receive radio messages, usually by Morse code. (…) Because the Doo transmitter was often left undisturbed, operational life was often a function of the battery life of its nickel-cadmium battery array. This advantage was often essential when the transmitter was utilized as a homing device. Because the device gave the appearance of fecal matter, it was often left undisturbed and thus a retained high efficiency as a homing beacon even when planted days or weeks before a mission.