P1g: Wireless signals Flashcards
Common uses of wireless technology (3)
TV and radio (radio waves)
mobile phones (microwaves)
laptop computers (radio waves e.g. Bluetooth and WiFi)
Advantages of EM radiation used for communication being reflected and refracted (2)
allows signal to be received that would otherwise be blocked by buildings and hills in the way
allows long distance communication as (radio) waves refract and reflect from the ionosphere
Disadvantages of EM radiation used for communication being reflected and refracted (2)
signals can lose too much energy and become too weak; drop in quality
interference with other signals of similar frequencies; drop in quality
What does long distance communication depend on? (2)
the refraction and resulting reflection of (radio) waves from the ionosphere (similar to TIR)
being received by and retransmitted from satellites (microwaves)
Why do nearby radio stations use different transmission frequencies
so the signals do not interfere with each other
Digital audio broadcasting radio (DAB radio) advantages (2)
more stations available
less chance of interference with other stations, so a clearer signal
Digital audio broadcasting radio (DAB radio) disadvantages (2)
not all areas of the UK are covered
sometimes the audio quality is not as good as FM; because sound is compressed, like an .mp3 file
How does refraction and diffraction of radiation affect communications? (2+1)
refraction at the interfaces of different layers of Earth’s atmosphere make it difficult to send the signal to where you want to
diffraction by transmission dishes result in signal loss
drop in quality
How are radio waves transmitted(2)
they are reflected from the ionosphere(TIR)
continued reflection by the ionosphere and the oceans allows radio waves to be received from an aerial that is not in line of sight
How are microwaves transmitted
they pass through the ionosphere and are received by orbiting satellites, amplified and retransmitted back to Earth
