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NOTE: To get off this list, send email to majordomo@aqua.ccwr.ac.za with the body of the message containing the line: unsubscribe sowacs Dear Dr. Brown, Your point is well taken that "sometimes stuff happens and we all learn". Indeed ESI values any feed back from users. It is never possible to test it in all situations and ESI has only made claims that MoisturePoint will work in most situations. ESI continues to push the boundaries of TDR usage for soil moisture measurement in difficult situations. As ESI's chief soil scientist I spend most of my time either working with clients on optimizing the performance of our MoisturePoint and GroPoint systems in fairly extreme conditions or on research for continued enhancement to both systems. Two internal MoisturePoint programs I am currently involved with are: (1) a future firmware upgrade that will have a new processing algorithm to produce more stable readings in noisy conditions; (2) the other program is a multi-segment type "K" profiling probe with dual feed points. Currently the signal is fed into a MoisturePoint multi-segment profiling probe at the centre of the probe. The signal is then directed across several segments of the probe. Therefore, in a conductive medium, not only the strength of signal decreases the further a segment is from the feed point but also the dispersion of the reflected signal increases. In the experiment mentioned in my previous e-mail I used type C probe, i.e. a ONE-SEGMENT probe with diode assembly at both ends. In a conductive medium, single segment probes suffer less signal attenuation than multi-segment probes. I also successfully used type "D" probe in a conductive medium. A "D" probe consists of two 15-cm segments with the signal-input point at the centre of the probe. Please refer to our newly published paper "The effect of soil electrical conductivity on moisture determination using time-domain reflectometry in sandy soil"-Canadian Journal of Soil Science, pp13-22, Feb. 2000. ESI's multi-segment profiling probes were designed for use in agricultural loamy soils and our patented diode switching technology helps MoisturePoint work in some conductive soils where other TDR instrument fail. Heavy conductive clay imposes a great challenge to TDR, but it is not insurmountable. ESI's new generation of signal-processing software and a multiple signal-input probe is designed to overcome the challenges of working in these difficult conditions. This work has been achieved by commitment and responding to feedback from our users. Z.J. Sun Ph.D. Research Scientist ESI Environmental Sensors Inc. 100-4243 Glanford Avenue Victoria, BC, Canada V8Z 4B9 Tel: 250-479-6588 Fax: 250-479-1412 e-mail: jason@esica.com