> > IF you can tolerate a rotating beacon of looker/listener if can ease the > task. Listeners can be on mobile target and fixed. Results on multiple scans can be compared. Signal will rise to a peak and fall again giving extra information (or less :-).) Scan rate can be quite high. Russell > > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .