ICOM 217800 Manuale Utente
88
10
ANTENNA TUNER OPERATION
10
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Antenna tuner operation
The internal automatic antenna tuner matches the
transceiver to the connected antenna automatically.
Once the tuner matches an antenna, the variable ca-
pacitor 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.
transceiver to the connected antenna automatically.
Once the tuner matches an antenna, the variable ca-
pacitor 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.
the transceiver. Be careful of the antenna selection.
TUNER OPERATION
➥Push the [TUNER] switch to turn the internal an-
tenna tuner ON. The antenna is tuned automati-
cally when the antenna SWR is higher than 1.5:1.
cally when the antenna SWR is higher than 1.5:1.
• When the tuner is ON, the [TUNER] switch lights.
[TUNER] switch
MANUAL TUNING
During SSB operation at low voice levels, the internal
tuner may not be tuned correctly. In such cases, man-
ual tuning is helpful.
tuner may not be tuned correctly. In such cases, man-
ual tuning is helpful.
➥Push [TUNER] for 1 sec., to start manual tuning.
• A side tone is emitted and [TUNER] blinks while tuning.
• If the tuner cannot reduce the SWR to less than 1.5:1
• If the tuner cannot reduce the SWR to less than 1.5:1
after 20 sec. of tuning, the [TUNER] switch indicator
goes out.
goes out.
Push [TUNER] for 1 sec.
AUTOMATIC TUNER START (HF bands only)
If you want to deactivate the tuner under conditions
of VSWR 1.5:1 or less, use the auto tuner start func-
tion and turn the tuner OFF. This function activates
the tuner automatically when the SWR exceeds 1.5:1.
of VSWR 1.5:1 or less, use the auto tuner start func-
tion 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. 99).
PTT TUNER START
The tuner is always tuned when the PTT is pushed
after the frequency is changed (more than 1% from
last-tuned frequency). This function removes the
“push and hold [TUNER]” operation and activates for
the first transmission on a new frequency.
after the frequency is changed (more than 1% from
last-tuned frequency). This function removes the
“push and hold [TUNER]” operation and activates for
the first transmission on a new frequency.
This function is turned ON in set mode. (p. 99).
NOTES:
• If the tuner cannot tune the antenna
Check the following and try again:
• the [ANT] connector selection.
• the antenna connection and feedline.
• the unaltered antenna SWR. (Less than 3:1 for HF bands;
• the antenna connection and feedline.
• the unaltered antenna SWR. (Less than 3:1 for HF bands;
Less than 2.5:1 for 50 MHz band)
• the transmit power. (8 W for HF bands; 15 W for 50 MHz
band)
• the power source voltage/capacity.
If the tuner cannot reduce the SWR to less than 1.5:1
after checking the above, perform the following:
after checking the above, perform the following:
• repeat manual tuning several times.
• tune with a 50 Ω dummy load and re-tune the antenna.
• turn power OFF and ON.
• adjust the antenna cable length.
• tune with a 50 Ω dummy load and re-tune the antenna.
• turn power OFF and ON.
• adjust the antenna cable length.
(This is effective for higher frequencies in some cases.)
• Tuning a narrow bandwidth antenna
Some antennas, especially for low bands, have a nar-
row bandwidth. These antennas may not be tuned at
the edge of their bandwidth, therefore, tune such an
antenna as follows:
row bandwidth. These antennas may not be tuned at
the edge of their bandwidth, therefore, tune such an
antenna as follows:
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.
1.5:1 at 3.55 MHz and an SWR of 3:1 at 3.8 MHz.
q Push [TUNER] to turn the antenna tuner ON.
w Select CW mode.
e Turn OFF the break-in function. (pgs. 4, 66)
r Push [TRANSMIT] to set to the transmit condition.
t Set 3.55 MHz and key down.
y Set 3.80 MHz and key down.
u Push [TRANSMIT] to return to the receive condition.
w Select CW mode.
e Turn OFF the break-in function. (pgs. 4, 66)
r Push [TRANSMIT] to set to the transmit condition.
t Set 3.55 MHz and key down.
y Set 3.80 MHz and key down.
u Push [TRANSMIT] to return to the receive condition.