"phil hunt" wrote in message
. ..
On Sun, 19 Oct 2003 03:57:04 -0400, John Keeney
wrote:

"phil hunt" wrote in message
...

LPI = Low probability of intercept. Usually a psuedo-random
spread-spectum
signal that looks like random noise to a typical radar warning
receiver.

Do you (or anyone else) have any estimate on how effective this is?

I don't know for a demonstrated (to me) fact, but in theory, it's danged
good.
Current LPI radar is one that has been adapted to spread spectrum
technology
which works well in radios and is hard to direction find against: good
clues
that it can be made to work as radar and is hard to intercept.

Anti-radiation missiles such as HARM or ALARM can detect radars. Can
they only detect older radars, or would they have some usefulness
against LPI radars too?

Anti-radiation missiles are in the same boat as any other DFing receiver,
the work on the same principles as other radio receivers, not magic.