Icom IC-7800 Instruction Manual - Page 138

10 ANTENNA TUNER OPERATION I Antenna tuner operation D Tuner operation [TUNER] • MANUAL TUNING • AUTOMATIC TUNER START (HF bands only) The internal automatic antenna tuner matches the transceiver to the connected antenna automatically. After the tuner matches an antenna, the variable capacitor angles are memorized as a preset point for each frequency range (100 kHz steps). Therefore, when you change the frequency range, the variable capacitors are automatically preset to the memorized point. CAUTION: NEVER transmit with the tuner ON when no antenna is connected. This will damage the transceiver. Be careful of the antenna selection. ➥ Push [TUNER] to turn the internal antenna tuner ON. The antenna is tuned automatically when the antenna SWR is higher than 1.5:1. • When the tuner is ON, [TUNER] switch indicator lights green. • While tuning, [TUNER] switch indicator blinks green. NOTES: • NEVER transmit without an antenna properly con- nected to antenna port in use. • When 2 or more antennas are connected, select the antenna to be used with [ANT]. • If the SWR is higher than about 1.5:1 when tuning above 100 kHz on an antenna's preset point, push [TUNER] for 1 sec. to start manual tuning. • The internal tuner may not be able to tune in AM mode. In such cases, push [TUNER] for 1 sec. to manually tune. During SSB operation at low voice levels, the internal tuner may not be tuned correctly. In such cases, manual tuning is helpful. ➥ Push [TUNER] for 1 sec., to start manual tuning. • A side tone is emitted and [TUNER] switch indicator blinks red while tuning. • If the tuner cannot reduce the SWR to less than 1.5:1 after 20 sec. of tuning, the [TUNER] switch indicator goes out. If you want to deactivate the tuner under conditions of VSWR 1.5:1 or less, use the auto tuner start function and turn the tuner OFF. This function activates the tuner automatically when the SWR exceeds 1.5:1. This function is turned ON in set mode. (p. 12-15). 10-5