Yaesu FT DX 1200 Operation Manual

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Page 65FT DX 1200 O PERATING M ANUALThe $utomatic $ntenna Tuner hereinafter referred to as the “$TU”) built into each FTDX 1200 is designed to ensure a0-2hm load for the ¿nal ampli¿er stage of the transmitter. We recommend that the $TU be used whenever you operateon the FTDX 1200.A DVICE : Because the $TU of the FTDX 1200 is located inside the station, it only adjusts the impedance presented to the trans-ceiver at the station end of your coaxial cable feedline. It does not “tune” the SW5 at the antenna feed point itself.When designing and building your antenna system, we recommend that every effort be made to ensure a low SW5at the antenna feed point. The $TU of the FTDX 1200 includes 100 memories for tuning data. (leven of these memories are allocated, one per$mateur band, so that each band has at least one setting preset for use on that band. The remaining 8 memories arereserved for the 8 most-recent tuning points, for Tuick freTuency change without the need to retune the $TU. The $TU in the FT DX 1200 is designed to match impedances within the range of 16. 2hms to 10 2hms, cor-responding to an SW5 of 31 or less on the 160 through 6 meter amateur bands. $ccordingly, simple non-resonantwhip antennas, along with random-length wires and the “G5V” antenna on most bands) may not be within the im-pedance matching range of the $TU.ATU OPERATIONU SING THE AUTOMATIC ANTENNA TUNER1. Use the 0ain Tuning 'ial knob to set the radio tothe desired operating freTuency within the $mateurband.. 3ress the [TUNE] button momentarily to place the$TU in the transmit line no adjustmenttuning willoccur yet). The “TUNER” icon will appear in thedisplay.QUICK POINT:The momentary press of the [TUNE] button will turnthe tuner on, and the microprocessor will automati-cally select the tuning point closest to the currentoperating freTuency.3. 3ress and hold in the [TUNE] button for one secondto begin automatic tuning. The transmitter will be en-gaged, and the “TUNER” icon will blink while tun-ing is in progress. When the optimum tuning pointhas been reached, the radio will return to receive,and the “TUNER” icon will again glow steadily in-stead of blinking).4. To disconnect the $TU from the transmit line, pressthe [TUNE] button momentarily. The “TUNER”icon will turn off, con¿rming that the $TU has beenturned off. In the “2ff” mode, the transceiver will bedirectly connected to the coaxial cable connected toyour antenna, and will respond to whatever imped-ance is present at the station end of the coax.A DVICE :The $TU circuit is located between the ¿nal ampli¿erand the rear-panel antenna jack reception is not affectedby the $TU.QUICK POINTS:$s shipped from the factory, only one $TU alignmentpoint is saved on each $mateur band. This was memo-ri]ed during the ¿nal alignment and performance veri¿-cation stages on the production line.N OTE:3lease check the operating freTuency before beginningthe tuning process, to be sure you are not interferingwith others who may already be using the freTuency.TERMINOLOGY:$ntenna Tuner 0emories The microprocessor of the$TU makes a note of the selected tuning capacitors andinductors, and stores the data for each 10 kH] windowin which tuning has occurred. This eliminates the needto re-tune every time you return to a freTuency on whichyou have already completed the tuning process.[TUNE] Button