The Coalition of the Swilling

Context? I actually may be able to help.

Doppler effect, Doppler radar, blahblahblah

In meteorology, the Doppler effect becomes especially useful. However, strictly speaking, the Doppler shift is too small with meteorological targets' speed to note the Doppler shift itself of a continuous emitting beam. Instead, what is used is a comparision of the phase between successive pulses, from a pulsed radar, coming back from the same targets. In wave mechanics, the intensity of the returned signal is:

Actually, I should have done it as one of Bill's dead ship quizzes.

What's to not understand, THS?

The Doppler effect is a well established phenomena where the frequency of a wave shaped signal apparently changes as either the source or the observer move. If you've ever listened to a train go by, and heard the horn fade away, you've seen, er, heard the Doppler effect. It's even trickier with satellites and VHF or UHF transceivers.

Doppler radar works a tad bit differently, since the target is moving, not the source or observer. Still, the phase shift is a reliable measurement of the Doppler effect. Since the target is moving, the changing signal of the returned radar pulse is measured in rapid succession to determine the relative motion of the target. This is possible, of course, because the original signal is known.

The trick, apparently, is to use wave mechanics for the computations, which is several notches above me.

Phase shifting is a highly reliable means of transmitting digital data over radio, even a weak signal. For example, a variation of "phase shift keying" is used to transmit images from space probes. But I never realized that phase comparisons were used for Doppler radar.

And, in case you were wondering, I'm a licensed Amateur Radio operator. Phase modulation and phase shifting are commonly used in radio signals, which, of course, radar is a variation of.

Thanks for the info, THS!

I live to serve.

major dad (who lives to explain things and does so marvelously in the most easy-to-comprehend-manner) jumped right into it last night when I asked "but how can they tell it's spinning?" He used both the sound change as a speeding vehicle approaches-then-passes and a person approaching who's throwing a ball at you every second. He never changes his rhythm, but you're plastered in balls as he gets closer and then they back off as he moves away. Then he found the Doppler radar entry for me to contemplate.

So was my wonderful FIL, jeffs! I think that's where major dad gets his love of all things electronic. Significant tax dollars also paid for my electronic training, but I've never had a knack for it and it's one of those things you need one for.

It appears that I have become unnecessary. The void has been filled.

(Sucks to be you.) I told you to stay up, but noooo...

Nice analogy by Major Dad, THS. Perhaps he has a bit of the teaching spark? ;-)

Yes, one needs a knack to comprehend electronics, at least so that you can troubleshoot problems. Or enjoy stacking and racking electronic systems throughout your home. I've been remodeling my place for a while, so my radios are mostly packed away. I still need to finish my portable automatic packet relay system......

Ken -- sorry about cutting you out. Perhaps this will console you.

And perhaps not.

Oh yeah he does, Jeff. He's the only way I got through school ~ NAND, NOR, capacitors, resistors, step-up, step-down, circuits: all being cheerfully explained over copious beers. The man's gifted.

The man's gifted.

Hmmmmm.....Mother's Day is this weekend, isn't it? I expect he already has his plans laid, but buttering up never hurts.

Oh trust me, with what he's agreed to do (sitting in a city park clean across the state for a whole weekend, just so I can try to sell a glass or two?), I need to be the serious kiss a$$.

Jeff, one suspects it's not just his plans that will be, er, L-word.

Oops, I need to watch my choice of words.....

BASTARD!