The time required for a signal to arrive at its destination is called propagation delay.

· Earth stations use parabolic antennas

· Uses for ships and vehicles

· Delays from 0.5 s to 5 s

· Extremely expensive

· operate in the low gigahertz range, typically at 11–14GHz.

· data rates are 1–10Mbps.

· sensitive to EMI and electronic eavesdropping,

Cable type
Cost
Installation
Distance
Other issues

Coaxial thinnet
Less than STP
Inexpensive easy
10 Mps 185m
Less sensitive to EMI than UTP

Coaxial thicknet
Greater than STP, less than fiber
easy
10 Mbps 500m
Less sensitive to EMI than UTP

Shielded twisted pair (STP)
Greater than UTP, less than Thicknet
Fairly easy
16 - 500 Mps 100m
Less sensitive to EMI than UTP

Unshielded twisted pair (UTP)
Lowest
Inexpensive easy
10 – 100 Mps 100m
Most sensitive to EMI

Fiber optic
highest
Expensive difficult
100 Mbs 10s of km
Insensitive to EMI

Infrared
Cheapest of all wireless
Fairly easy, may require line of sight
10 Mbps Under a kilometer
Can attentuate due to fao and rain

Laser
Similar to infrared
Requires line of sight
Can span several kilometres
Can attentuate due to fog and rain

Narrow band radio
More expensive than infrared and laser
Requires trained technician and can involve radio towers
Can span hundreads of kilometres
Low power devices can attentuate to fog, rain and solar flares

Spread spectrum radio
More advanced technology than narrow band radio and more expensive
Requires trained technician and can involve radio towers
Can span hundreads of kilometres
Low power devices can attentuate to fog, rain and solar flares

Microwave
Very expensive as requires link to satellite
Requires trained technician and involve satellite dishes
1 – 10Mbps Can span thousands of kilometres
Can attentuate to ofg, rain and solar flares, long ping

























































C2. Research the modern trends in transmission mediums.



These days are quite expanding technology which uses as a transmission mediums power lines. It is because electricity is available to everyone and frequency of electric current is different than signal what we use in networking. Power lines can offer quite high bandwidth and there is no need to pay to telephone companies or get a new cable.



For powerline communication to work, power grids must be retrofitted with adapters that change data signals into frequencies that can be carried over electrical lines. At the residential level, computers are outfitted with a special modem that separates electricity from data.