Radio Frequency (RF) Hardware:

Antenna:

Antennas were first used in 1888 by Heinrich Hertz (1857-1894) to prove the existence of electromagnetic waves predicted by the theory of James Clerk Maxwell.

Antenna as architecture, designs of antenna (monopole or whip, helical, loop and many others), the relationship between antenna length and wavelength (for monopole wavelength/4), a spatial constraint, passive and active antennas, DIY material use (eg. cantenna)

Architecture: spray or paint/draw on antenna:

http://www.free2air.org/story/2001/11/8/04055/3981

Intervention:

Jamming of signals, resonance and induction, body as resonator, metal in buildings as Faraday cage, cars as diffusion grating (again a question of wavelength)

Material:

Household materials such as silver foil, a rusted razor blade, a needle for a crystal radio receiver, diodes and transistors using germanium, copper wire

Radiotelescopy:

At lower end of the spectrum, reasonably high frequencies imply large antenna and an architecture.

Reception:

Probing for emissions, antenna of course and a relation to intention (unknown, unseen, snooping) - the message. Signal strength (RSSI). Detection, filtering, demodulation of a signal if necessary, amplification.

Transmission:

Emission. Power and ground/earth. Antenna again of course and modulation.

InfraRed (IR), “Visible” and UltraViolet (UV)

Phototransistors, photodiodes, light-to-sound (A directional, enclosed detector is amplified.)