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Well, I did mention in another thread that Cecil had already passed
the milepost indicating the point of no return: On Tue, 04 Dec 2007 19:16:01 GMT, Cecil Moore wrote: I also measured ~12-13 ns delay through 50 turns of the same coil stock that Tom was using when he measured a 3 ns delay through a 100 turn coil. The "results" (not corrected for errors as all of Cecil's arguments drawn from reality are cast as perfections - a clash that always amuses me) at this point Cecil confirmed/validated Tom's screen shot. How? Tom's instrument is built to compensate for two channel measurement errors, an ordinary scope is not. There are many issues to resolve when using an ordinary scope before results (then corrected for error) can be used in comparison. Why? The error is an inherent disparity in using two channels, and their different rise times. It shouldn't take a degree in engineering (many who own scopes can confirm this) to realize that an identical event, traveling through the parallel chain of amplifiers eventually driving the deflection of the parallel traces; each of those in the pair will arrive at a different time. What? It only remains to resolve which chain presents more (or less) rise time. It is not uncommon to find in the extreme (exactly where Cecil's measurement resides) that rise time differentials can easily equal the time delay measurement cited above in the quote, but for Leader O'Scopes, a calibrated model can exhibit up to 17.5nS rise time. Remove that differential, and the error corrected delay collapses towards Tom's results! If we consider the span of all error easily washes over the resolution of the measurement, then Cecil's particular test was a non-starter as it is arguable that it was ever performed. Cecil could yet pull some of this error out of the mud, but his memory is foggy, he can't find things, problems beset him, poor eyesight may have disturbed what he reported (transcription error), his instrumentation isn't calibrated, he even admits to the possibility of spelling errors (communication failures in this forum seem to be embraced as a mark of populist heroism in the face of sterile engineering), and on and on until: SUDDENLY a new fact arises that completely vindicates Cecil! A new vigor rises, and there are more than 20 answers to supply! Memory suddenly clears, the lost notebooks are found, problems vanish, eyesight is restored to 20/20.... well, let's say that drama takes center stage as the magician's cape opening reveals the rabbit. There are other errors to answer for, this one was simply the first to engage Cecil in his stumbling attempt cursing the pebbles in the path as boulders. The absolute best outcome Cecil could reasonably expect to show is the standard RL of an ordinary coil, and Corum would have to wait for a future validation. Of course, this future occasion would demand far better controls, tighter readings, better reporting; and, of course, this verges on the dictates of engineering. The cursing will, no doubt, follow. :-) 73's Richard Clark, KB7QHC |
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