Functions For Transmit - Icom IC-78 Instruction Manual

4
OPERATION
n Functions for transmit
ï Output power and microphone gain
• Setting output power
q Push [SET] for 1 sec. to select quick set mode.
w Push [Z DN]/[UP Y] to select "RF POWER".
e Rotate the main dial to select the desired output.
• Output power is displayed in 101 steps (L, 1–99 and
H) but is continuously selectable.
• Available power
SSB/CW/RTTY:
AM :
*Carrier power
ï Meter function
The bar meter in the function display acts as an S-
meter (for relative signal strength) during receive
and can be selected for one of three functions dur-
ing transmit.
• Push [SET] to select the PO, ALC and SWR meter
mode.
• Measuring SWR
q Confirm that the output power is over 30 W.
w Push [SET] to select the SWR meter.
e Push [MODE] to select CW or RTTY operation.
• Key down or push [PTT] to transmit; then read
the actual SWR from the meter:
≤1.5; well matched antenna
≥1.5; check antenna or cable connection, etc.
16
2 (or less) to 100 W
2 (or less) to 35 W*
Maximum output
power is selected.
• Setting microphone gain
Microphone gain must be adjusted properly so that
your signal does not distort when transmitted.
q Select SSB or AM mode.
w Push [SET] for 1 sec. to enter the quick set mode.
e Push [Z DN]/[UP Y] to select "MIC GAIN".
r Adjust the mic gain while speaking into the micro-
phone, so that the ALC meter does not exceed the
ALC zone.
t Push [SET] to exit quick set mode.
ALC zone
Display
Indication
PO Indicates the relative RF output power.
Indicates the ALC level. When the meter
movement shows the input signal level ex-
ceeds the allowable level, the ALC limits the
ALC
RF power. In such cases, reduce the micro-
phone gain (see above).
SWR Indicates the SWR over the transmission line.
The best match is in this range.
Microphone gain is
set to 50.
Measurement