7510 Comms

EM waves are ​ (a)   ​ waves with electric and magnetic fields at ​ (b)   angles to each other and the direction of ​ (c)  

• transverse
• right
• propagation
• transversal
• transversly
• left
• amplitude

What is the speed of light?

Label the diagram

e

f

g

h

d

c

b

a

VHF

EHF

VLF

MF

HF

SHF

UHF

LF

What is the frequency for HF?

• 30MHz-300MHz

• 3MHz-30MHz

• 300MHz-3GHz

• 3kHz-30kHz

What are the primary modes radio waves travel?

• Ground Wave

• Sky Wave

• Space Wave

• Satellite Wave

radio waves can be​ (a)   , (b)   and ​ (c)   .

• reflected
• refracted
• diffracted
• long
• short
• encrypted

Ground waves are (a)   around the earth and bend over the horizon for several thousand miles.

• diffracted
• refracted
• reflected

Sky waves are (a)   through the ionosphere and bend back to earth many thousand miles over the horizon and with reflection from the earth’s surface they can obtain worldwide communications.

• refracted
• diffracted
• reflected

(a)   waves travel in straight lines only out to the horizon but​ (b)   range communication can be obtained with​ (c)  

• Space
• long
• satellites
• Ground
• Sky
• short
• towers

Very High Frequencies (VHF and above) travel best as (a)   waves.

• space
• ground
• sky