Dave, The HTX202 manual is online at Support.RadioShack.Com. http://support.radioshack.com/support_electronics/15563.htm The advice the other Dave gave sounds right. IIRC, a common cause of E01 can be caused by RF feeding back in from the rubberduck into the top-side power connector -- never use external power without a coax antenna extender. 73 Bill N1VUX