Joe,

Tanks but most of RFIDs takes more than 50mSec to respond & its costlier slution to use readymade tags

Instade i m trying to use 12 different rf frequencies
& to use PLL at receiver to identify perticular frequency so that itself it will act as an identification.

My problems r with rf receiver
as Hal mentioned spark plug noise will be major resource.

I need some guideline to work with rf receiver.

Thanks