Yaesu FT-857 Operation Manual

Also see for FT-857 series: Manual Technical supplement Brochure & specs Operating manual Technical supplement

Contents

Yaesu FT-857 Operation Manual Manual pdf 70 page image

68 FT-857 Operating ManualA CTIVE-TUNING A NTENNA SYSTEM (ATAS-100/-120) OPERATIONThe optional ATAS-100/-120 Active-Tuning Antenna System provides operation on a numberof HF bands (7/14/21/28 MHz) plus 50 MHz, 144 MHz, and 430 MHz. The FT-857 pro-vides microprocessor control of the tuning mechanism in the ATAS-100/-120 for conve-nient automatic tuning.Before operation can begin, you must instruct theFT-857’s microprocessor that the ATAS-100/-120 is being used. This is done using the Menu Mode:1. Press and hold in the [FUNC] key for one second to activate the Menu mode.2. Rotate the SELECT knob to recall Menu Mode No-001 [EXT MENU], then rotate theDIAL to change the setting to “ON” to enable the extended Menu Mode.3. Rotate the SELECT knob to recall Menu Mode N0-085 [TUNER/ATAS]. The defaultsetting for this Menu is “OFF.” Rotate the DIAL to change the setting to “ATAS (ALL),”if you are using the ATAS-100/-120 for all bands (you must connect an external diplexerto combine the two antenna ports so as to use the ATAS-100/-120 on all bands). Ormake the setting “ATAS (HF&50),” if you are using the ATAS-100/-120 on 7 ~ 50MHz, with a dual-band VHF/UHF antenna connected separately to the 144/430 MHzantenna port. If you are just using the ATAS-100/-120 on the HF bands only, with adual-band VHF/UHF antenna connected separately to the 144/430 MHz antenna port(no 50 MHz operation) make the setting “ATAS (HF).”4. Press and hold in the [FUNC] key for one second to save the new setting and exit tonormal operation.Automatic Tuning1. Press the [FUNC] key, then rotate the SELECT knob as needed, to recall Multi Func-tion Row “k” [TUNE, DOWN, UP].2. Press the [A](TUNE) key to turn the ATAS-100/-120 on (this action only supplies volt-age to the antenna at this point; re-tuning does not begin). The “ATAS” will appear on theLCD.3. Now press and hold in the [A](TUNE) key for one second to initiate ATAS-100/-120tuning. The transmitter will automatically be activated, a carrier will be sent, and theantenna’s length will be adjusted for best SWR.4. If the microprocessor determines that the antenna’s length is radically incorrect from theoptimum value, no carrier will be sent out. Instead, in the receive mode, the antenna willretract to its longest or shortest position (this may take up to one minute). While this ishappening, do not press the [A](TUNE) key again.When the ATAS-100/-120 reaches its minimum length, automatic tuning will be initi-ated, and the transmitter will automatically shut off when a satisfactory SWR is achieved.5. On the 144 MHz and 430 MHz bands, the ATAS-100/-120 does not require a tuningprocess. SWR will be satisfactory when the antenna is fully retracted.TRANSMITTER OPERATION