Icom IC-7300 Instruction Manual basic - Page 53

7 ANTENNA TUNER OPERATION About the internal antenna tuner The internal automatic antenna tuner automatically matches the transceiver to the antenna within the range of 16.7 ~ 150 Ω (SWR of less than 3:1). After the tuner matches an antenna, the latching relay combinations are memorized as a preset point for each frequency range (100 kHz steps). Therefore, when you change the frequency range, the latching relay combinations are automatically preset to the memorized point for fast tuning. ••When you install a new antenna, or you want to change the antenna settings, you can clear the all of the internal antenna tuner preset points with the "" item on the TUNER set screen. (p. 8-3) MENU » SET > Function > Tuner > ••You can select whether or not to save the internal antenna tuner's status after pushing TUNER on each band in the "[TUNER] Switch" item on the TUNER set screen. (p. 8-3) MENU » SET > Function > Tuner > [TUNER] Switch NOTE: When the transceiver receives a strong physical shock, the internal latching relays may be returned to an unlatched condition. In that case, push TUNER to turn OFF the tuner, then turn ON again to reset the all latching relays. Internal antenna tuner operation 1. Push TUNER to turn ON the internal antenna tuner. 1 ••"TUNE" is displayed when the tuner is ON. 2. Tune the antenna. 2 LTo tune the antenna, see "Manual tuning" or "PTT Tuner start" below. 3 DDManual tuning 4 You can manually tune the antenna before transmitting. 1. Hold down TUNER for 1 second to start manual 5 tuning. ••The tuner reduces the SWR to less than 1.5:1 after 6 2~3 seconds of tuning. LWhile tuning, a side tone is heard and "TUNE" blinks 7 red. 2. After tuning, "TUNE" is displayed. 8 LIf the tuner cannot reduce the SWR to less than 1.5:1 after 20 seconds, tuning stops and "TUNE" goes out. 9 DDPTT Tuner start 10 The tuner is always activated when PTT is pushed after the frequency is changed (more than 1% from 11 last-tuned frequency). This function tunes the antenna for the first transmission on a new frequency. LThis function can be turned ON in the "PTT Start" 12 item of the TUNER set screen. (p. 8-3) MENU » SET > Function > Tuner > PTT Start 13 NOTE: ••If the SWR is higher than about 1.5:1 when tuning more than 100 kHz on an antenna's preset point, hold down [TUNER] for 1 second to start manual tuning. ••If you transmit into a high SWR, "TUNE" may blink. In that case, hold down TUNER for 1 second to manually tune. 14 15 16 17 If the tuner cannot tune the antenna ••Repeat manual tuning several times. 18 ••Even if the tuner cannot tune the antenna on the first tuning, it may success at the second tuning. 19 ••Some antennas, especially for the low bands, have a narrow bandwidth. These antennas may not tune at 20 the edge of their bandwidth, therefore, tune such an antenna as follows: 21 (Example): Suppose you have an antenna which has an SWR of 1.5:1 at 3.55 MHz and an SWR of 3:1 at 3.8 MHz. 1. Set 3.55 MHz, and hold down TUNER for 1 second to start manual tuning. 2. Set 3.80 MHz, and hold down TUNER for 1 second to start manual tuning. 7-1