Yaesu FT-897D Operating Manual

Also see for FT-897: Manual Brochure & specs Technical supplement Service manual Operating manual

Contents

Page 10 FT-897D OPERATING MANUALLINEAR AMPLIFIER I NTERFACINGThe FT-897D provides the switching and drive-control linesrequired for easy interfacing to most all commonly-avail-able amplifiers sold today.These include: The Antenna Jacks (“HF/50MHz” and “144/430MHz”); A T/R control line (open circuit on RX, closure to groundon TX); and A negative-going ALC jack (control voltage range: 0Vto –4V DC). When interfacing to the VL-1000 Solid State 1 KW Lin-ear Amplifier, the optional CT-58 Interface Cable pro-vides for easy interconnection (requires that the MenuMode No-020 [CAT/LIN/TUN] setting changes to “LIN-EAR”).The rear-panel CAT/LINEAR jack is an 8-pin, miniatureDIN type, with the “TX GND” pin providing a closure toground on transmit, for T/R control of your linear amplifier.The ACC jack is a miniature stereo type, with external ALCinput capability on the tip connection. The main shaft is theground return. The ring connection of the ACC jack, whenclosed to ground, places the FT-897D into the transmit mode,and sends a steady CW carrier, for amplifier (or antennatuner) adjustment purposes.Typical amplifier interface circuits are shown below.Note that some amplifiers, particularly VHF or UHF “brick”amplifiers, offer two methods of T/R switching: applicationof +13V or a closure to ground.Be sure to configure your amplifier so that it switches via aclosure to ground, as provided by your FT-897D’s CAT/LINEAR jack (“TX GND” pin). Alternatively, many of theseamplifiers use “RF Sensing” to control their relays; if yoursis in this category, you may then use the T/R control linefrom the “TX GND” pin of the CAT/LINEAR jack forcontrol of your HF linear amplifier, and RF sensing for yourVHF or UHF amplifier.The “TX GND” T/R control line is a transistor “open col-lector” circuit, capable of handling positive amplifier relaycoil voltages of up to +50V DC and current of up to 400mA. If you plan on using multiple linear amplifiers for dif-ferent bands, you must provide external band-switching ofthe “TX GND” relay control line from the CAT/LINEARjack.Important Note!Do not exceed the maximum voltage or current ratingsfor the “TX GND” line at the CAT/LINEAR jack. Thisline is not compatible with negative DC voltages, norAC voltages of any magnitude.Most amplifier control relay systems require only lowDC voltage/current switching capability (typically, +12VDC at 25 ~ 75 mA), and the switching transistor in theFT-897D will easily accommodate such amplifiers.I NSTALLATIONANT 1ANT 2REMOTEONOFFBAND DATA 1BAND DATA 2GNDALC 2ALC 1PTT 2PTT 1 INPUT 1INPUT 2CONTROLDC48V INTo HF AntennaTo HF AntennaTo 50 MHz AntennaINPUT 1VL-1000ANT 1ANT 2ANT 3BAND-DATA 1CAT/LINEARTo 144 / 430 MHz AntennaALC 1CT-58 BAND DATA CableCT-58 ALC CableGNDDC 48V INCONTROL*The “CT-58” consists of two separate cables: the BAND DATA cable (Part # T9101500) and the ALC Cable (T9101501).