Hi Group,

I am working on a project which will detect if a automobile is running. My
thoughts are to use a common 455KHz IF filter and amplitude detect or a 10.7
MHz IF filter and do the same.

Which frequency would be better or easier? (455KHz or 10.7MHz)

I would expect that with 455KHz, I could use common op-amps to get the gain up
to a good level to detect the noise from the spark plug?

Any thoughts and direction for a direct conversion to something that would turn
on an LED?

How about a super-reg? It has a wideband width?

Anyone recall any articles on simple receivers?

How about other frequencies like VHF?