<HTML>In a message dated 8/9/02 10:52:37 AM Central Daylight Time, sckline@attbi.com (Susan Kline) writes: <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Well, now that we've settled THAT ... <grin> See, you have a sense of humor after all, Bill. Susa</BLOCKQUOTE>n And glad you saw it that way.  Actually, if you haven't ever read my article, "What the Hell is Reverse Well?", it is in my website.  It pretty much explains everything I know about why this occurs.  I really am about as much mystified by it as anyone else but I've been observing the problem for a long time and think I know some, but not all of the reasons for it. John Travis was the first to identify it some 50 years ago but he did not give it a label.  When a pattern does develop (and it isn't always there), it is the result of *cumulative* errors, however small they may be. Even the use of ETD's can produce this effect.  In this case, I think irregular scaling and erroneous programming may contribute to it. One thing I will say is that you and David L. are correct, advanced aural tuning techniques which many but not all people have today will largely prevent this error from occurring.  I always stress the importance of learning to use the contiguous 3rds technique.  Also, the study of HT's, even if the technician does not personally believe in the use of them, will make the person aware of when an erroneous pattern is developing.  I have two apprentices, neither of which make this error.  They don't make the error because they are being taught what it is and how it should be avoided. Richard's observation probably means that among the people he knows and has observed, all have been taught to tune a true ET and do so.  I never went looking for this, I only have found it to my surprise and in the most unlikely circumstances. Bill Bremmer RPT Madison, Wisconsin <A HREF="http://www.billbremmer.com/">Click here: -=w w w . b i l l b r e m m e r . c o m =-</A> </HTML>