Alarms: Ultrasonic vs Microwave sensors

[HappyPuppy]

Which is better for movement detection? (ie. which one will go off when some joker sticks a coat hanger through the top seal of the driver side window to try and reach that little unlocking switch)

I know Microwave sensors are what people use for soft-tops, but I've read in some forums that people with hard-top cars swear by them. My other question is why? Why would a microwave sensor be better than an ultrasonic?

[Jay95R33]

Happy,

Ultrasonics are more prone to false alarms due to sun/heat etc.

Ultrasonics effectivly send out thier ultrasonic waves which bounch off of the interior of the car, they can only monitor the space inside the cabin etc.

While microwaves can be set up (dual zone ones) to monitor both inside the car, and also outside the car.

With the outside zone, you can set it up (if your good) so it will detect movement 2-3 inches outside the car. so it won't go off if someone walks past the car, but if somebody goes to open the door, puts something on the top of your car, goes up close to the window to look in etc, the alarm will go off.

I know that with the old ultrasonics you couldn't leave your window down a few inches to let the air curculate either. Cause it's pick up the hot air movement and set the alarm off.

With the microwaves you can leave your window right down and it will make little or no difference.

J