On Sat, 07 Jan 2006 11:28:12 -0800, RST Engineering wrote:

Back in the '60s and early '70s I did some work with Impatt and Gunn diodes,
building a little self-detecting doppler for speed sensing. However, 35
years have passed and my notebooks for that stuff are somewhere in a dusty
archive along with my venerable sliderule.

Is there a cheap source for onesies-twosies of a radar front-end that will
give me doppler audio as a function of a large metal object's speed at a
range of 20 meters or so? I don't need to go into production on this thing,
just build one. A surplus source would be ideal.

It seems that the little kids on our rural country lane have all become
teenagers at once and are trying to outdo the others in how fast they can
drive daddy's car up and down the lane. We've lost one dog this week and
unless I can put up some sort of a siren that goes off when they exceed some
agreed upon limit, the carnage will continue.

Just call your local cop shop, and find out where they get their radar
guns - if these kids are posing a threat to life and limb, the cops might
come out and do it for you.

Good Luck!
Rich