Here's some easy modifications to improve the rx audio fidelity of Kenwood TS-440's. All references below are to the IF board component designations. * Increase C60 to a .47uf or 1 uf. This will increase low frequency response on all modes. * Decrease C51 to .01 uf. This will increase high frequency response on SSB/CW. * Try removing R263 (tacked on the bottom of the board on my early production unit). This will lower in amplitude the audio coming out of the detectors and improved the smoothness (a real technical term) of the audio, especially on AM signals. And, of course, I take no responsibilty for anything you do to your radio. Be careful. The IF board on the 440' is about the easiest one to get at. 73/Dave n2fam@ka3fmo.pa ======================================================================== Note: I haven't tried or verified this, proceed at your own risk. WA2ISE TS-440S MODIFICATION TO USE ANTENNA TUNER FOR XT AND RX.- Remove case from rig. Remove (4) screws that holds antenna tuner in place. Next slide antenna tuner out to get to the coax connections. Remove the input coax attached to antenna tuner from FO connector on filter unit (X51-340-00). Remove coax from out connector on antenna tuner and install in FO CONNECTOR ON FILTER UNIT. Unplug and remove switch unit (X41-1610-00 N-14) from rig. Remove short wire from antenna connector to PC BOARD. Cut coax on the input connector of antenna tuner in half and connect cut the end to switch unit PC BOARD where short antenna wire was removed and shield to ground. Solder other half of coax to antenna connector and shield to ground, and plug other end into output connector of antenna tuner. You still have control of antenna tuner with auto and thru switch. It works very well. Maybe someone can use this idea. N2EDE, Box 680-S, Roanoke, VA. 24012. Newsgroups: rec.radio.amateur.misc From: wa2ise@cbnewsb.cb.att.com (robert.f.casey) Subject: TS440 receiver audio mods file Message-ID: <1993Mar24.130853.8959@cbfsb.cb.att.com> Keywords: mods Sender: news@cbfsb.cb.att.com Organization: AT&T Date: Wed, 24 Mar 1993 13:08:53 GMT Lines: 29 copied from packet: Msg# TSF Size #Rd Date Time From MsgID To 38513 BF 1520 0 19-Mar 2236 N2FAM 2890_WA2OLZ MOD@USBBS () Sb: TS-440 RX Audio Mods Here's some easy modifications to improve the rx audio fidelity of Kenwood TS-440's. All references below are to the IF board component designations. * Increase C60 to a .47uf or 1 uf. This will increase low frequency response on all modes. * Decrease C51 to .01 uf. This will increase high frequency response on SSB/CW. * Try removing R263 (tacked on the bottom of the board on my early production unit). This will lower in amplitude the audio coming out of the detectors and improved the smoothness (a real technical term) of the audio, especially on AM signals. And, of course, I take no responsibilty for anything you do to your radio. Be careful. The IF board on the 440' is about the easiest one to get at. 73/Dave n2fam@ka3fmo.pa ======================================================================== Note: I haven't tried or verified this, proceed at your own risk. WA2ISE TS-440S MODIFICATION TO USE ANTENNA TUNER FOR XT AND RX.- Remove case from rig. Remove (4) screws that holds antenna tuner in place. Next slide antenna tuner out to get to the coax connections. Remove the input coax attached to antenna tuner from FO connector on filter unit (X51-340-00). Remove coax from out connector on antenna tuner and install in FO CONNECTOR ON FILTER UNIT. Unplug and remove switch unit (X41-1610-00 N-14) from rig. Remove short wire from antenna connector to PC BOARD. Cut coax on the input connector of antenna tuner in half and connect cut the end to switch unit PC BOARD where short antenna wire was removed and shield to ground. Solder other half of coax to antenna connector and shield to ground, and plug other end into output connector of antenna tuner. You still have control of antenna tuner with auto and thru switch. It works very well. Maybe someone can use this idea. N2EDE, Box 680-S, Roanoke, VA. 24012.