What is a Jammer?

Tucson company Raytheon just won a major contract to develop upgraded radar jammers to the US Navy for the F/A-18s. I thought this would be a good opportunity to explain radar jamming. My first notion of radar jamming came from the 1987 Star Wars spoof, Spaceballs. So, I felt the need to include a clip of the radar jamming scene below.

This scene inspired me to ask 25 years ago, “What is radar jamming?” 

Jamming a radar is a way to prevent antagonist from effectively detecting an object. Before I get into jamming, let me give a brief explanation of radars. Radars are able to detect objects distance from a radar receiver, the speed of the objects they are detecting, and in some cases the angle of the object relative to the radar’s current position. If you do not want the radar to know this information, you jam the radar.

What a jammer does is make the radar not be able to do all of those things. However, you know when you are being jammed. So, think about as if someone does not want you to see them and they poke you in the eye, you cannot see and know you have been poked in the eye. On a side note, when someone cannot see you and they do not know you are there that is stealth.

The way the most jammers work is they figure out what frequency the antagonist radar is at (think of a radar frequency as just like a radio frequency, it is basically the station you are transmitting your radar at.) Then they send out a stronger signal of noise (gibberish) at a higher magnitude or power than your radio to drown out your information from the radar. It is like when you are watching TV when someone is vacuuming in your house to cover up the sound of the vacuum you increase the volume of the TV. Think about jamming as turning up the volume on their signal to try to disrupt it except instead of sound radars use radio signals.



 

 

To counter jamming, the radar can change its frequency like constantly changing stations so the jammer cannot block the message. Like when you change stations when the static for one station gets too bad.

Radar jamming is one type of way to prevent a radar from figuring where you are and how fast you are going. Electronic attack (EA) is what jamming and other ways to prevent a radar from working are called. The list of things that can be done to prevent EA is called electronic counter-measures (ECM). I will talk about more of these in another blog.