Positive Earth RC-D710? http://www.aprs.org/D710-HT.html Does not have a diode in the supply. www.ew.usna.edu/~bruninga/aprs/RC-D710-connx-pwr.GIF Has a diode in... 73. Dave g0wbx. This mail has been scanned by Palmer Cook Computer Services Limited. www.palmercook.co.uk