EQT 2 Elementart Principles Of Radio Flashcards Preview

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Flashcards in EQT 2 Elementart Principles Of Radio Deck (16):
1

What is attenuation

Radio waves reduce in strength over time and distance.

Amplitude decreases. The wavelength and frequency remain unchanged.

2

How do you overcome attenuation

Use very high frequencies

3

What are the wave bands between?

Electrical energy (lower end)

Infa red energy (upper end)

4

What are the frequency bands?

VLF
LF
MF
HF
VHF
UHF
SHF
EHF

5

What is the wavelength spectrum and size for VLF

Spectrum 3-30khz

Wavelength 100km to 10km

6

What are the frequency spectrum and wavelength size for VHF

30-300mhz

10m to 1m

7

What are the frequency spectrum and wavelength size for UHF

300mhz - 3ghz

1m to 10cm

8

What are the characteristics of VLF

Long range

Big aerial and high power

Prone to static

9

What are the characteristics of LF/MF

Reliable long range

Congested

Static interference/night effect

Used for NDBs

10

What are the characteristics of HF?

Long distance

Long range comms by day

Static interference

Used for RTF comms

11

What are the characteristics of VHF/UHF

Line of sight

Free of static interference

Prone to ducting

Used for RTF/ILS/VOR/VDF/PSR/SSR

12

What are the characteristics of SHF/EHF

Short range

Severe attenuation

Used for RAD/ATC/PAR/Wx RAD

13

What is a ducted wave?

A marked temperature decrease plus rapid decrease in humidity causes wave to bounce between the surface and top of the duct. This means VHF UHF SHF can travel unusually long distances.

14

What is an indirect wave

Similar to ducting

Low frequency waves will bend around objects and be herd great distances from the source.

Low frequency means less attenuation

15

What frequencies use direct wave

VHF and higher

16

What can limit a direct wave

Curve of earth

A/C height