Sky and Space Wave Propagation

Introduction

What do you understand from the terms Sky and Space wave propagations? These two are the types of radio wave propagation along with ground wave propagation. In sky wave propagation electromagnetic waves were reflected from the ionosphere in the atmosphere. Space wave propagation is transmitted from one antenna to another antenna in the troposphere.

In this article, we will discuss the topic of Sky and Space wave propagations from physics along with the advantages and disadvantages of both and where they are being applied. 

Let’s start the article by defining  Sky Wave Propagation

Sky Wave Propagation

Sky wave propagation is a kind of radio wave propagation. This wave propagation helps in communicating at long distances in the frequency ranges from a few MHz to 30 MHz or 40 MHz. In Sky wave propagation, radio waves were reflected by the ionosphere or ionised layer back towards the earth. The ionosphere can reflect the waves because of the presence of a large number of charged particles or ions. This sphere extends from 65 km height from the earth to  400 km above. Sky wave propagation is used by the services for shortwave broadcasts. Skip is another name for Sky wave propagation. 

The mathematical representation for the sky wave propagation is:

fc=9Nmax

Where, 

 fc = critical frequency in Hz

Nmax = max. Electron density per m3

Skip Distance is the minimum distance from the radio signal transmitted to the surface of the earth. 

Skip distance can be given by 

Dskip= 2h (fmuffc)2-1

Where, 

fmuf is max. usable frequency

Dskip is skip distance

h is the height from where the reflection happened

fc= critical frequency

Sky Wave Propagation Advantages

1. It supports propagation at large distances.
2. Loss of radio waves or debilitation is low due to atmospheric conditions.
3. The frequency range of operation is high.
4. It provides continuous support in different types of communication.
5. Sky wave propagation is a simple mode of propagation.

Sky Wave Propagation Disadvantages

1. There is variation in the signal transmission in day and night time due to the presence of ionosphere near during night and far during night time.
2. There is a requirement of big sized antennas for long-distance or sky wave propagation.
3. Sky wave propagation travels between multiple hops before reaching the receiver which in turn reduces the strength of the waves considerably.

Sky Wave Propagation Applications

This type of radio wave propagation is usually used in satellite and mobile communication.

Space Wave Propagation

Space wave propagation can be described as a type of radio wave propagation. In this propagation, the radio waves are being transmitted either from one antenna to another antenna directly or getting reflected from the ground. Space wave propagation is achieved in the atmosphere’s tropospheric region. Thus, Tropospheric wave propagation is another name for space wave propagation. The frequencies are usually greater than 30 or 40 MHz. The troposphere is extended up to 20 km above the surface of the earth. 

To calculate the height and distance between the antenna to prevent the loss of signal can be given as:

Dm = (2RHt)–12 +  (2RHr)–12

Where, 

R = earth’s radius

Ht = height of transmitting antenna

Hr = height of receiving antenna

Dm = Distance between the antennas

Space wave propagation advantages

1. To overcome the limitations of other wave propagations, i.e. sky wave propagation and ground wave propagation 
2. Allows a large range of frequencies.

Space Wave Propagation disadvantages

1. Space wave propagation happens in the line of sight distance
2. Signals get affected due to the earth curvature.

Space Wave Propagation Applications

This type of radio wave propagation is usually used in satellite and radar communication. Space wave propagation can also be used in microwave linking applications.

Difference between  Sky Wave Propagation and Space Wave Propagation

Conclusion

In the above article, we have defined the sky and space wave propagation. Both are the types of radio waves transmitting while both are different from one another. 

Along with the meaning of sky and space wave propagation, we have described their advantages, disadvantages and other related topics to solve your queries.