The built-in automatic antenna tuner works on all bands in both transmit and receive modes. The TS-870S requires 13.8 VDC at 20.5 amps. RADIOHF - TS-870S Serial Numbers > 1996-70 mil > 1997-80 mil > 1998-90 mil > 1999-00 mil > 2000-10 mil > 2001-20 mil > 2002-30 mil > 2003-40 mil > 2004-50 mil > Late 2004-early 2005 60 mil last production run. Early models 701XXXXX thru 806xxxxx had problems and any s/n after these runs have all the latest updates. There were some factory refurbs that failed final inspection at time of mfg. They had S/N of 90 mil and 00 mil sold by dealers in 2002 and 2003. (source N4ATS )
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