Difference Between Shortwave Vs. Longwave Radio
Do you think all the radio stations air their programs in the same way?
There’re shortwave radio, long wave radio, and the recent additions- FM, and internet radios. All of them are used in different contexts, locations, audiences and different needs. So the answer must be a NO!
But where exactly lies the difference?
In this article, we’ll discuss this difference in the light of short wave and long wave radio.
As their names indicate, the differences are mainly in the wavelength and frequency. Therefore, to understand these radios you first have to understand the wavelength, frequency. In short, the general study of wavelength and frequency.
In the EM spectrum, every band has its respective frequency and wavelength range. And all kinds of radio waves range between 3 Kilohertz (KHz) to about 300 Gigahertz (GHz).
Wavelength and Frequency
The wavelength and frequency have a vice versa relation. Regarding physics, they are inversely proportional to each other. Therefore, higher frequencies correspond to the shorter wavelength. And that again corresponds to higher energy. And Vice versa.
Long waves (radio) are between 30 KHz to 279 KHz having an average wavelength of 1500 meters. On the other hand, Shortwaves range between 1.5MHz to 30MHz (wavelength is between 10 to 85 meters.)
LW travels over the ground covering greater distances within a given amount of power. LW frequencies tend to follow a straight line. Instead of bouncing off the ionosphere, they more likely pierce it. Then they return to earth.
SWs, on the other hand, tend to follow the earth’s curvature. They interact with the atmosphere and ionosphere. These layers of air skip them to great distances. Thus they can travel past the horizon.
Antenna and Reception
Again, sending signals through long waves require lengthy antennae. This makes long wave stations inconvenient to operate and look as well. On the other hand, SW requires much smaller antennae that make the SW band favorable.
Buildings or other natural terrains can’t block the path of long waves easily. But shortwaves get blocked more easily as they don’t bounce off the atmosphere.
Again, on the contrary of long waves, short waves are more energetic. Therefore they use more power to travel.
But there’s a little confusion that many people often have. Don’t mess shortwaves with the shortwave band. It’s because that band still contains long wave frequencies. Those frequencies are just shorter than the lower bands (high-frequency region). But actually of long waves.
We already learned about different groups in the radio spectrum. Longwave (LW), medium wave (MW), shortwave (SW) and so on. The FCC also divided radio spectrum into different bands. That’s why the confusion creates.
These bands start from very low frequency (VLF) and go up to extremely high frequency (EHF). For maritime and navigation, people use VLF and LF. And satellite and radio astronomy use the highest bands.
Short wave radio covers a huge range; huge times greater than long wave radio. Even SW transmissions are so easy to receive that even cheaper radios can pick up a signal. That’s why its use is also many times more than long wave radio.
Again, it’s capable of reaching a nation that doesn’t even have a radio network. What the locals do is that they create an audio content first. Then they send it out of the country from where it’s beamed back. All this happens via a shortwave transmission. This also cuts the risk of prosecution. I think now you have a clear idea of the strength of the shortwave transmission.
In countries like Yemen, supportive radio contexts are broadcasting in this way. Listeners can access them privately as well as anonymously.
That’s how SW effectively reaches the remote audiences. It makes it a powerful way to unify marginalized communities.
Turning on an SW radio, you can access through the broadcast of other countries as well. Thus, it earned the nickname ‘world band radio’. And that’s why the use of SW transmissions is so wide. They cover miles from the transmitter crossing ocean and mountain ranges. In short, it has broken the boundaries of nations, whether political or geographical.
On the contrary, people use long waves for maritime purposes. In fact, long wave transmission was used first when the radio was in its earlier period. They were able to send signals over long distances using less power. As ships at sea required this service most, they were the earliest users of this transmission. That’s why they named them as maritime bands those are of the lowest frequency.
As we mentioned above, LW travels longer distances using much higher power than FM and DAB. The Typical power levels are 500 KW which may rise to 2 MW by some stations. Its coverage ‘per kilowatt’ is better than similarly powered transmitter on MW band. That's why it's favorable for wide area coverage.
The use of LW band is mainly noticed in Europe though not exclusively. Many North African and Middle East countries also use this band. Although many often consider it as an obsolete band, it’s completely not true. Millions of people already listen to LW stations. Also, there are planning to increase LW radio stations.
So if you ask about the future of LW radio stations, one thing is sure. There could be an audience as there are already 60 million LW radios still in use along in the UK. And it’s a greater number than DAB radios. LW signal can pervade every part of a country. So in future, there’s a high possibility of creating an appetite among its listeners.
Finally, all radio waves, short or long, belong to electromagnetic radiation like the light. So both of them travel at the same speed as light. It’s constant at vacuum space and denoted by c. Also, both of their speed change when rain, air, and other objects obstacle them. See, there aren’t many differences between them. Especially over short distances.
The major differences lie in the field of their use based on their strength and power. That is, Amplitude Modulation (AM) radio stations use long wave transmissions. On the other hand, short waves are in use for all other sorts of modes. Such as broadcast station, ham radio, transoceanic aircraft, military, weather fax, etc.
I hope this article made you understand the differences well.