Electromagnetic Waves

Electromagnetic waves exist on the electromagnetic spectrum. This includes these broad categories:

• Gamma-rays

• X-rays

• Utraviolet Light

• Visible Light

• Infrared Light

• Microwaves

• Radio waves

Even though they all have different effects and utilities within our world, the same unifying principle of electromagnetic waves brings them all together. They ALL travel at the speed of light when in vacuum. The key way their behaviour changes is through their change of frequency. Gamma-rays exist at the absolute highest frequencies, while radio waves exist at the lowest frequencies.

Radio waves have long wavelengths, low frequencies, and low energy, while Gamma-rays have short wavelengths, high frequencies, and high energy.

Refraction

Attenuation

Electromagnetic Waves for Mariners

Considerable amounts of Radio waves part of the spectrum are dedicated to maritime application. Bands of frequencies are dedicated to various purposes, and the reason for bands is to allow for multiple systems to use the same concepts without interfering with each other. If you and someone else broadcast on exactly the same frequency, you will interfere with one another. When communicating this may be fine (as you can listen and then talk), but when using RADAR this is not the case and you will want to be on different frequencies.

Marine Radar

Marine Radar uses the following frequency bands:

2.9GHz to 3.1GHz - referred to as X Band Radar 8.85GHz to 9GHz - referred to as S Band Radar

There is a third band, 5.47GHz ot 5.65GHz, but it never really caught on in equipment manufacture of usage.

Marine Radio

Marine Radio is used for communication.

Visible Light

Light is used for sight (of course), but the specifics come in to play when using very precise sights such as for Celestial Navigation.