Beam and it's follow-on I-Beam are sets of programs to produce coverage charts of radio sources. It has been used for RADAR, DME, VOR and various communications sources specific to aviation. However, it is also valid for cell phone, TV and radio towers
1. In radio interferometry, the inverse Fourier transform of the u-v sampling distribution, or of a weighted u-v sampling distribution, possibly convolved with a gridding convolution function: the idealized response to a point, or unresolved, radio source. 2. A numerical approximation to 1. 3. A digitized version of 2, sampled on a regular grid (usually regarded as an image). 4. Synonymous with point spread function. 5. (Occasionally) as above, but taking into account instrumental effects, so that the beam depends on position in the sky. See dirty image. Occasionally, any one of the above, other than 5, is termed the synthesized beam.