Editing TV and FM DX (section)

==Earth – Moon – Earth (EME) propagation (Moonbounce)==
Since 1953, radio amateurs have been experimenting with lunar communications by reflecting VHF and UHF signals off the [[Moon]]. [[EME (communications)|Moonbounce]] allows communication on Earth between any two points that can observe the Moon at a common time.<ref>{{cite web | title=''Space&Beyond'': Moonbounce Advances the State of the Radio Art | work=ARRL, the national association for Amateur Radio | url=http://www.arrl.org/news/features/2002/01/21/1/ | access-date=May 5, 2005 |archive-url = https://web.archive.org/web/20050414115309/http://www.arrl.org/news/features/2002/01/21/1/ |archive-date = April 14, 2005}}</ref>

Since [[the Moon]]'s mean distance from Earth is {{convert|239000|mi|km}}, path losses are very high. It follows that a typical 240 [[decibel|dB]] total path loss places great demand on high-gain receiving antennas, high-power transmissions, and sensitive receiving systems. Even when all these factors are observed, the resulting signal level is often just above the noise.

Because of the low [[signal-to-noise ratio]], as with amateur-radio practice, EME signals can generally only be detected using narrow-band receiving systems. This means that the only aspect of the TV signal that could be detected is the field scan modulation (AM vision carrier). FM broadcast signals also feature wide frequency modulation, hence EME reception is generally not possible. There are no published records of VHF/UHF EME amateur radio contacts using FM.

===Notable Earth-Moon-Earth (EME) DX receptions===
During the mid-1970s, John Yurek, K3PGP,<ref>{{cite web|url=http://www.k3pgp.org/uhftveme.htm|title=K3PGP – Experimenters Corner – K3PGP UHF TV reception via EME (1970)|website=www.k3pgp.org}}</ref> using a home-constructed, 24-foot (7.3 m), 0.6-focal-diameter [[Parabolic reflector|parabolic]] dish and UHF TV dipole feed-point tuned to channel 68, received KVST-68 [[Los Angeles]] (1200 kW ERP) and WBTB-68 [[Newark, New Jersey]] via moonbounce.  At the time of the experiment there were only two known transmitters operating in the United States on UHF television channel 68, the main reason why this channel was selected for EME experiments.

For three nights in December 1978, [[astronomer]] Dr. [[Woodruff T. Sullivan III]] used the 305-metre [[Arecibo Observatory|Arecibo radio telescope]] to observe the Moon at a variety of frequencies. This experiment demonstrated that the lunar surface is capable of reflecting [[Terrestrial television|terrestrial]] band III (175 – 230 MHz) television signals back to Earth.<ref>{{cite web | title=Eavesdropping Mode and Radio Leakage from Earth | work=NASA CP-2156 Life In The Universe | url=https://history.nasa.gov/CP-2156/ch5.4.htm | access-date=April 26, 2005}}</ref> While not yet confirmed, FM broadcast EME reception may also be possible using the Arecibo dish antenna.

In 2002, [[physicist]] Dr. Tony Mann demonstrated that a single high-gain UHF [[yagi antenna]], low noise masthead preamplifier, VHF/UHF synthesised communications receiver, and personal computer with [[Fast Fourier transform|FFT]] [[Spectrum analyzer|spectrum analyser]] software could be used to successfully detect extremely weak UHF television carriers via EME.<ref>{{cite web|url=http://internal.physics.uwa.edu.au/~agm/eme.html|title=UHF TV carrier detection by moonbounce (EME)|website=internal.physics.uwa.edu.au}}</ref>