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How a Radar Jammer Can Be Made at Home


Make a Radar Transmitter at Home

This is an example of a finished radar jammer

This is an example of a finished radar jammer

Most road users wanting to make better time on the open road will arm themselves with an expensive radar detector. However, this purchased gadget will not work against a gun-type radar unit, a unit in which the radar signal is not present until the highway patrol has your automobile in his sights and pulls the trigger. Then, it is too late to slow down.

A better way to safely make better time is to continuously jam any signal with a radar signal of your own. When I tested with the help of a local police officer, her device displayed random numbers when I was driving towards her. Building a low-power radar transmitter is very simple.

What Is a Radar Transmitter?

When encased in the proper size resonator, a special semiconductor named a Gunn diode will transmit microwaves when hooked up to 5 to 10 volts DC. This voltage can be sourced in-car by using an 8 to 3 terminal regulator. These regulators can be picked up at almost any auto-electrical shop.

Patrol officer radars usually operate on the K band at 22 GHz, or more often than not on the X band at 10.525 GHz. Pretty much all microwave intruder alarms and motion detectors (mounted over automatic doors in supermarkets, etc.) contain a Gunn type transmitter/receiver combination that transmits about 10 milliwatts at 10.525 ghz.

These devices work perfectly as radar jammers. If you can't get any in your area, write to Microwave Associates in Burlington, Mass. and ask for info on "Gunnplexers" for ham radio use.

The finished jammer can be mounted outside the automobile, in a waterproof enclosure, or on the dash. When on the open road, switch on the power.

How to Test Your Unit

Correct construction and fine-tuning your radar jammer can be difficult if you don't have good measuring equipment for microwaves. One simple way to test your unit is to use a conventional radar detector, preferably one that indicates which band the radar is transmitting on.

Interesting Side Effects

Your device will not jam radar behind the automobile or to the side, so be careful when passing speed traps regardless. Something interesting to observe is that any vehicle in front of you fitted with a detector will hit their brakes as you come up to large flat objects. Their detectors are being triggered by the signal your jammer is transmitting, bouncing off objects.


Many people go through the hassle to legally beat speeding tickets and pour thousands of dollars into fines and fighting them. Why not just build this little device and avoid them altogether?

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.


jack on August 21, 2020:

can i make a police outfit

stump jummper on January 08, 2020:

I just put 2 microwave on my hood and pluged them up crankked them to 2500 watts and they melted the tires off the fuzz car

Acekey244 on January 03, 2020:

I have onr built into my sterio system as a capacitor.

Dirdudada on October 08, 2018:

Use of a radar jammer is an FCC violation punishable by a fine of up to $50,000 and 10 years in prison. It will be obvious to the cop that you're using a jammer and your life will become a living hell.

These days, police are so well armed with speed sensing equipment that it's better to just take your car to a track if you want to drive fast.

Gary North Carolina on August 02, 2017:


How can this possibly work? If using the part from Motion activated door, and then using a RADAR detector to test Jammed police Radar, then I hate to say it but other RADAR units in other police cars would be jamming each other and we know that doesnt happen. Basically we need the exact frequency that X, K and KA operate on and then build a transmitter with about 3xs the power output. Then we will be jamming Radar because the info they get back on that frequency wont be what they sent out as my signal is 3xs stronger and therefore their signal should get mixed up with mine or JAMMED. Any way you can give me the plans for building what I discribed if I get you the correct frequencies?

DeeAda04 on August 13, 2016:

Camel Toker, spoken like a true idiot

drake on March 20, 2016:

just saw this same post on the dark web

Hack on February 03, 2015:

No, that is an example of a gun diode with wires. Any digital gun will ignore that.

Johnf378 on July 20, 2014:

This will be a fantastic site, will you be interested in doing an interview regarding just how you designed it? If so email me! edabeeddbeek

Camel Toker on March 31, 2014:

Exposure to Microwave Radiation is worse than a speeding ticket. So, choose wisely.

CarNoobz from USA on February 04, 2013:

Haha! That's cool. Voted up

Dave on December 15, 2012:

Ok so... where are the plans to build this????

Tom on April 18, 2012:

This is not what i what

johnsams (author) on June 14, 2010:

Hi Paul, I am not sure about the sweepable jammer, but you may be able to find more info on this website http://www.bombshock.com/cars/ cheers!

paul jones on March 13, 2010:

ok, sounds great! but how do i go about building it? i would like to build a sweepable jammer so that i can adjust the frequencey range that it jams/transmits. any ideas?

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