There are a number of companies that offer passive radar/laser scramblers to US and International customers.
Rocky Mountain Radar, Passive Scrambler Maker
Depending on the products offered the claims of passive scramblers state the product will scramble X, K, Ka, laser.
One passive scrambler is the Rocky Mountain Radar Phazer II, a radar scrambler only; while two other Rocky Mountain Radar products, Rocky Mountain Radar C430 and C450, are radar/laser detectors combined with radar/laser scrambling.
LM Services, Passive Scrambler Maker
The only other company offering passive scramblers (Mirage 2001) is LM Services of Thornton, CO. If you are interested in reviewing the Rocky Mountain Radar products, El Paso, Texas.
See each description, or review product info at the Rocky Mountain Radar web site.
Rocky Mountain Radar VS LM Services
The primary differences between the Rocky Mountain Radar Phazer II and Mirage 2001 is the Phazer II provides a 2 square inch reflecting antenna, and the Mirage 2001 provides a 6 square inch reflecting antenna.
As a passive scrambler the Mirage has three times more radar signal/noise reflection, but neither product has shown effective radar scrambling at typical distances of 200 feet to 2500 feet from the radar gun.
The C430 and C450 claim to go the extra mile by also detecting radar/laser, as well as scramble radar and laser. They too have small reflector antennas.
The barn was effectively an audio reflecting antenna. It received an audio signal (your voice) and reflected the audio signal back to your ears (the audio receiver.)
When radar is triggered from a radar gun, it travels down the highway as an invisible wave and is referred to as the RF signal. As the signal travels down the highway, it grows in height and width and gets progressively weaker in strength as it moves away from the radar gun. By the time an RF signal strikes the front of your car at 1000 feet, it is 1 million times weaker than when it was first triggered.
The average car offers about 1000 square inches of reflective surface area. A passive scrambler typically has 2 square inches of reflective antenna.
When the RF signal strikes the car/truck, it also strikes the passive scrambler and the reflection is now called the Doppler Signal, since it changes frequency somewhat as a result of the reflection. The net result is 1000 inches of RF Doppler Signal reflection combined with 2 square inches of Scrambler chirp noise.
Even to a person who dislikes math, one can divide (1000/2) and come up with a 500:1 ratio of vehicle Doppler strength over the passive scrambler strength.
Since the passive scrambler is not designed to transmit, it can not come close to enough power to defeat the larger vehicle Doppler signal
A potential buyer of Passive Radar Scramblers should question the claims offered by Rocky Mountain Radar, the largest manufacturer of passive scramblers. When a claim is made about jamming to within 100 feet, (the "punch-through" distance where the radar gun overpowers the FM Chirp Signal of a Passive Scrambler), Rocky Mountain Radar should be able to prove it with written test reports and/or videos from Speed Measurement Labs (SML), the recognized authority in this field.
However, Speed Measurement Labs has shown a multitude of times that Passive Radar Scramblers are ineffective from two miles, 1 mile, 1/2 mile, all the way to the radar gun; so, how is it possible that a Passive Scrambler can provide the advertised 100 foot "punch-through" protection? They can't! But the words sound so good, that people simply believe the words, and forget to ask for actual test proof. RMR can't provide performance test results from neither SML or Speedtest proving their products work.