gjw@floyd.UUCP (Greg Wroclawski) (09/27/83)
A couple of years ago i got my hands on some brochures from radar manufacturers. The two big ones seem to be Kustom Electronics and MPH Industries (clever). Kustom Electronics had three hand held models of police radar. HR-4, HR-8, and HR-12. All of these units were K band and from reading the brochure all transmitted microwaves continuously. This should dispell a myth that all "gun radar" can shoot a burst of microwaves and nail you. What the trigger does is take a reading when it is pulled by enableing the counter circuits and that reading is held unit it is pulled again. However, I do believe that the HR-12 did have an "instant on" option. Radar units cannot simply be turned on and quickly take a reading because all of them use a Gunn diode oscillator as the microwave source and these drift wildly upon initial turn on until they become thermally stable. What the units with instant on capability do is short out the Gunn diode cavity with a PIN diode so no microwaves can reach the antenna until the bias on the PIN diode is reversed. The most sophisticated radar seems to be the Kustom Electronics KR-11. This unit has a dash mounted antenna and has instant on capability. In addition it has a short pulse moving mode which can supposedly fool many cheap radar detectors which cannot pick up the short randomly spaced pulses needed to keep track of the patrol car speed. The MPH Industries model K-55 also has a instant on option which is available on request. This unit also has a dash mounted antenna with a seperate readout console. So it seems that either hand held or fixed radar can be of the "instant on" type. Here in New Jersey which claims to have the most radar units per capita of any state the most popular unit by far is the K-55. This travesty occured when the state decided to by 4000 of the units several years ago and ditributed them to all the state police and the remaining ones to municipalities. From my experience with my radar detector I have yet to go through a speed trap where the radar was being used in the instant on mode. I must admit I don't know what percentage of the K-55's are equipped with instant on.