Yaesu FT-897 Operating Manual

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Page 41FT-897 OPERATING MANUALFC-30 AUTOMATIC ANTENNA T UNER O PERATIONThe optional FC-30 Automatic Antenna Tuner provides au-tomatic tuning of a coaxial line so as to present a nominal50 Ω impedance to the FT-897’s HF/50 MHz antenna port.Before operation can begin, you must instruct the FT-897’smicroprocessor that the FC-30 is being used. This is doneusing the Menu Mode:1. Press and hold in the [F] key for one second to activatethe Menu mode.2. Rotate the MEM/VFO CH knob to recall Menu ModeNo-001 [EXT MENU], then rotate the DIAL to changethe setting to “ON” to enable the extended Menu Mode.3. Rotate the MEM/VFO CH knob to recall Menu ModeNo-020 [CAT/LIN/TUN]. The default setting for thisMenu is “CAT.” Rotate the DIAL to change the setting to“TUNER.”4. Press and hold in the [F] key for one second to save thenew setting and exit, then turn the transceiver off.5. Set up the FC-30 and FT-897 per the illustration, thenturn on the transceiver’s power again. Do not set upthe FC-30 and FT-897 before changing the MenuMode, item No-020 [CAT/LIN/TUN].6. Press and hold in the [F] key for one second to activatethe Menu mode.7. Rotate the MEM/VFO CH knob to recall Menu Mode No-085 [TUNER/ATAS]. The default setting for this Menu is“OFF.” Rotate the DIAL to change the setting to “TUNER.”8. Press and hold in the [F] key for one second to save thenew setting and exit.Operation is similar to the procedure for the ATAS-100/-120:1. Press the [F] key, as needed, to recall Multi FunctionRow “k” [TUNE, DOWN, UP].2. Press the [A](TUNE) key to turn the FC-30 on. “Paren-theses” will appear on both sides of the “TUNE” indica-tion, and the “TUNE” will appear on the LCD.3. Press and hold in the [A](TUNE) key to initiate automatictuning. The FT-897 transmitter will be activated, a car-rier signal will be sent out, and the coils and capacitors inthe FC-30 will be selected/adjusted for optimum SWR.When tuning is complete, the transmission will cease, andyou will be ready for operation on this frequency.Tuning data will be stored in the FC-30’sMemory system. See the discussion below fordetails on how this works.TRANSMITTER O PERATIONAntenna Tuner Memory SystemThe FC-30, working in concert with the FT-897, can storeimpedance matching data in its micro-computer memory, soas to provide instant adjustment as you transmit in differentareas of a particular band. A total of 100 memories are pro-vided: 11 of these are “general” memories apportioned oneper band, while the remaining 89 are allocated for specificfrequency data within the various bands, with the capabilityto resolve new tuning data every 10 kHz. A few guidelinesshould be noted regarding the FC-30’s memory system:Tuning data is stored when you make an active effort to storeit by pressing and holding in the [A](TUNE) key for onesecond. Although the tuner will automatically activate itselfif it encounters more than 1.5:1 SWR, this memory will notbe stored unless you have pressed the [A](TUNE) key forone second. This allows you to store your favorite operatingfrequency areas into tuner memory without tying up memoryspace with matching data on seldom-used frequencies.If the FC-30 cannot resolve a satisfactory match becausethe SWR is above 3:1 (2:1 on the 50 MHz band), the tuningprocess will stop, and no memory data will be stored. How-ever, you may wish to move frequency a few kHz, then pressthe [A](TUNE) key again for one second, as slight changesin the reactance may allow a match to be obtained. Then goback to the original frequency and try again.Another technique which may allow matching in some situ-ations is to add a few feet or meters of coaxial cable on the“antenna side” of the FC-30. This will change the imped-ance transformation taking place in the coaxial cable, possi-bly moving the impedance presented to the FC-30 into anacceptable range. Note that this is not changing the actualantenna SWR, but only the impedance “seen” by the FC-30’s matching circuits.If your antenna system presents an SWR of less than 1.5:1,you may wish to turn off the antenna tuner, as full transmit-ter power will be delivered to the antenna system withoutintervention by the FC-30.If the impedance encountered by the FC-30 exceeds 3:1,and the “HI SWR” icon is illuminated, the microprocessorwill not retain the tuning data for that frequency, as the FC-30 presumes that you will want to adjust or repair your an-tenna system so as to correct the high SWR condition.G NDDATA ACC KEYANTIN PUT22 ATRXSuppliedCoaxial CableTo 144MHz/ Antenna430MHzCAT/LINEARCTRL144MHz/430MHzHF/50MHzANTTo HF/50MHz AntennaControl Cable