Earth-Moon-Earth, also known as moon bounce, is a radio communications technique which relies on the propagation of radio waves from an earth-based transmitter directed via reflection from the surface of the moon back to an earth-based receiver.
Amateur radio (HS4KFF)
Amateur radio, often called hamradio, is both a hobby and a service that uses various types of radio communications equipment to communicate with other radio amateurs for public service, recreation and self-training. A participant is called an amateur radio operator, or a ham
Amateur radio operators have personal wireless communications with friends, family members, and even complete strangers, and often support their communities with emergency and disaster communications while increasing their personal knowledge of electronics and radio theory. An estimated six million people throughout the world are regularly involved with amateur radio
The term "amateur" is not a reflection on the skills of the participants, which are often quite advanced; rather, "amateur" indicates that amateur radio communications are not allowed to be made for commercial or money-making purposes.
Though its origins can be traced to at least the late 1800s, amateur radio, as practiced today, began in the 1920s. As with radio in general, the birth of amateur radio was strongly associated with various amateur experimenters and hobbyists. Throughout its history, amateur radio enthusiasts have made significant contributions to science, engineering, industry, and social services. Research by amateur radio operators has founded new industries, built economies, empowered nations, and saved lives in times of emergency.Though its origins can be traced to at least the late 1800s, amateur radio, as practiced today, began in the 1920s. As with radio in general, the birth of amateur radio was strongly associated with various amateur experimenters and hobbyists. Throughout its history, amateur radio enthusiasts have made significant contributions to science, engineering, industry, and social services. Research by amateur radio operators has founded new industries, built economies, empowered nations, and saved lives in times of emergency.
Activities and practices (HS4KFF)
Radio amateurs use various modes of transmission to communicate. Voice transmissions are most common, with some such as frequency modulation (FM) offering high quality audio, and others such as single sideband (SSB) offering more reliable communications when signals are marginal and bandwidth is restricted Radiotelegraphy using Morse code remains popular, particularly on the shortwave bands and for experimental work such as Moonbounce, with its inherent signal-to-noise ratio advantages. Morse, using internationally agreed code groups, also facilitates communications between amateurs who speak different languages.[3] It is also popular with homebrewers as CW-only transmitters are simpler to construct. For many years, demonstrating a proficiency in Morse code was a requirement to obtain amateur licenses for the high frequency bands, but following changes in international regulations in 2003, many countries have now dropped this requirement (the United States Federal Communications Commission did so in 2007).
Current EME communications (HS4KFF)
As the albedo of the moon is very low (around 12%), and the path loss over the 770,000 kilometre return distance is extreme (around 309 db), high power (more than 100 watts) and high-gain antennas (more than 35 db) must be used. In practice, this limits the use of this technique to the spectrum at VHF and above. Recent advances in digital signal processing have allowed EME contacts, admittedly with low data rate, to take place with powers in the order of 100 Watts and a single Yagi antenna. moon bounce" technique was developed by the United States Military in the years after World War II, with the first successful reception of echoes off the moon being carried out at Fort Monmouth, New Jersey on January 10, 1946 by John H. DeWitt as part of Project Diana. This was followed by more practical uses, including a teletype link between the naval base at Pearl Harbor, Hawaii and United States Navy headquarters in Washington, DC. In the days before communications satellites, a link free of the vagaries of ionospheric propagation was revolutionary. Later, the technique was used by non-military commercial users, and the first amateur detection of signals from the moon took place in 1953.
