Icom IC-7610 Instruction Manual basic - Page 51

7 ANTENNA TUNER OPERATION Using the Internal antenna tuner 1. Push TUNER to turn ON the internal antenna tuner. ••The indicator on the TUNER key lights. 2. Tune the antenna. LTo tune the antenna, see "Manual tuning" or "PTT Tuner start" below. DDManual tuning You can manually tune the antenna before transmitting for the first time. 1. Hold down TUNER for 1 second to start manual tuning. ••The tuning normally takes 2~3 seconds. ••The indicator on the TUNER key blinks red. 2. After tuning, the indicator on the TUNER key lights white, and the internal antenna tuner stays ON. LIf the tuner cannot tune, the indicator on the TUNER key goes out, and the tuning circuit is automatically bypassed. DDPTT Tuner start The tuner is always activated when [PTT] is pushed after the frequency is changed (more than 1% from the 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" item on the TUNER screen. (p. 8-3) MENU » SET > Function > Tuner > PTT Start 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 the tuner cannot tune the antenna ••Repeat manual tuning several times. ••Even if the tuner cannot tune the antenna on the first tuning, it may success at the second tuning. ••Some antennas, especially for the low bands, have a narrow bandwidth. These antennas may not tune at the edge of their bandwidth, therefore, tune such an antenna as follows: (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. About an external antenna tuner The optional AH-4 antenna tuner matches the IC-7610 to a long wire antenna more than 7 m/23 ft long (3.5 MHz and above). In addition, using the optional AH-2b antenna element matches the IC-7610 to a whip antenna more than 2.5 m/8.2 ft long (7 ~ 50 MHz). The optional AH-740 automatic tuning antenna covers 2.5 to 30 MHz range with the whip antenna that is supplied with the AH-740. R DANGER HIGH VOLTAGE! NEVER touch the antenna element while tuning or transmitting. Always install it in a secure place. NEVER operate the AH-4 or AH-740 without an antenna connected. The tuner and transceiver will be damaged. DDUsing the AH-4 or AH-740 1. Turn ON the transceiver. ••"TUNE" is displayed. LEach time you push TUNER , the AH-4 or AH-740 is turned ON (the indicator on the TUNER key lights) or OFF (bypassed). 2. Hold down TUNER for 1 second to start manual tuning. ••The tuner reduces the SWR to less than 2:1 after 2~3 seconds of tuning. LWhile tuning, a side tone is heard and the indicator on the TUNER key blinks red. LIf the tuner cannot reduce the SWR to less than 2:1 after 15 seconds of tuning, the indicator goes out. 3. After tuning, the indicator stops blinking and lights white. LWhen the long wire antenna cannot be tuned, the indicator goes out. In that case, the AH-4 is bypassed and the wire is directly connected. NOTE: When the wire antenna cannot be tuned, check the wire length and connection. Note that the AH-4 cannot tune a wire that is a ½λ long or on a multiple of that frequency. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 7-3