[Calvin Locke]

Nowadays, isn't it possible to use that sig as "radar"?

[TechJunkYard]

Nowadays, isn't it possible to use that sig as "radar"?

For DME and speed measurement, I would say no -- the waves are too big. For example, a quarter-wave at WBT's freq (1.11MHz.) is (246/1.11=221.621) over 221 FEET long. That kind of wavelength propogates in different ways during the day and night, and won't bounce off objects.... and the bounce is what you want for radar. The time to get the return blip tells you how far away the target is, and the phase shift of the blip tells you how fast it's moving (relative to you).

For position targeting, again, nah. We've got GPS now. Since President BJ turned off Selective Availability, GPS is more than adequate to use for aiming bombs and missles. But if you wanted to destroy the transmitter site, that AM sig would be the thing to use.

[TechJunkYard]

Or perhaps you're thinking of the old "Russian Woodpecker" noise on HF, which used over-the-horizon-backscatter techniques to detect Russian missles. The Russkies, of course, used the same techniques to keep an eye on us. Uses "shortwave" spectrum where the radiated signals are a little shorter than in the broadcast band (quarter-wave at 5 MHz. is "only" 49 feet).

Now mostly obsolete for this purpose, NOAA is experimenting with parts of the system for weather prediction.

This stuff was a real pain in my ear back in my HF DXing days.