Gravitational Engineering - What We Can Do Now

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For r>>d that expression turns into g ~= 2*G*m/r^2 + G*m*d^2/r^4, the variable component here is G*m*d^2/r^4. If we manage to fix one of the ends still, then we get the variable component as G*m*d/r^3.

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Dream on AB. Dealing with you is a waste of time.

<BLOCKQUOTE id=quote><font size=2 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>[LB]1) Mount a light bulb (or LED) next to transmitter crystal and drive it the with (a signal derived from) the signal used to drive the crystal.

2) Mount a photo detector next to the receiver crystal and monitor it with one of the scope channels.<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>That's not an easy thing to do. You need about 50 picosecond-sharp light pulse. Only some very special LEDs and lasers can do that. The usual cheap trick is to feed the simple LEDs with short reverse-polarity pulses of about 40 V amplitude but limiting the total charge flowing through the LED during the pulse so that it's not destroyed. And then there's a problem with a fast enough detector for the light pulse...
So the parallel photonic channel intro'es more problems than it solves them.

(the joke about the light bulb was good, though...<img src=icon_smile_big.gif border=0 align=middle>)

Oops. Good points.

When I first thought up the idea for the control channel it was in relation to the Walker Dual experiment (with 40 Hz sine waves most everywhere). You could actually use a light bulb there (they can be modulated up to about 100 Hz, depending on size).

Guess it needs a little updating ... Hmm. Neon bulb? too dim, needs an HV drive circuit. How about a strobe light? A school science lab is likely to have one. But probably not one that goes to several hundred KHz, or MHz.

OK, how about this. If we shield the receiver <b>only</b> against EMI, leaving the transmitter unsheilded, we could put an antenna on the receiver and use that as our control channel?

Regards,
LB

<BLOCKQUOTE id=quote><font size=2 face="Verdana, Arial, Helvetica" id=quote>quote:<hr height=1 noshade id=quote>[LB] OK, how about this. If we shield the receiver <b>only</b> against EMI, leaving the transmitter unsheilded, we could put an antenna on the receiver and use that as our control channel?<hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face="Verdana, Arial, Helvetica" size=2 id=quote>Sure can be done. Use the second channel of the oscilloscope for that.
But then again, if we feed huge voltage pulses into the xmtr, we'd better shield the beast up well, or we'll get lost in all kinds of parasite signals and reflections bouncing around the parts of the setup. Still we can do that a few times for the sake of calibration check and pristine conscience, and then proceed without it.

Let's please keep this discussion entirely about the experiments, and drop all further remarks about the participants, their competence, motives, intelligence, education, lineage, or whatever.

Note that saying an idea is stupid is still <i>ad hominem</i> because intelligence is not an attribute of ideas but of their proposer. There is no need to characterize ideas at all. Just stick to the facts. They speak well for themselves.

And the side that prevails on any issue has no need to gloat. The shoe might be on the other foot next time. -|Tom|-

The preceding post [now deleted] contained offensive, ad hominem remarks that I censored. This message is an example of baiting, disrespectful messages that we plan to keep off this board, which will remain about science and not the personalities that participate. (Even the uncensored parts were on thin ice because they contained remarks about the person, not the ideas.)

I hereby ask the Moderator to enforce this guideline. Repeated violations will cost the perpetrators their rights to post messages here.

I thank everyone for their cooperation. -|Tom|-