Radio FM is transmitted in the Very High Frequency (VHF, 30 MHz to 300 MHz) radio spectrum. VHF radio waves act more like light, traveling in straight lines; hence the reception range is generally limited to about . During unusual upper atmospheric conditions, FM signals are occasionally reflected back towards the Earth by the ionosphere, resulting in long distance FM reception. FM receivers are subject to the capture effect, which causes the radio to only receive the strongest signal when multiple signals appear on the same frequency. FM receivers are relatively immune to lightning and spark interference. High power is useful
2002 AA29 reflects radio waves only weakly. In the former case it would have to have an unusually high albedo. This would be evidence in support of the speculation that it, or at least the material of which it is composed, is different from most other asteroids so far discovered on near-Earth orbits, or represents a fragment thrown off by the collision of a medium-sized asteroid with the Earth or the Moon. Using radar echo measurements at the Arecibo radio telescope the rotational period of could be determined. In this radar astronomy procedure radio waves of known wavelength are emitted from a