Icom IC-720 Instruction Manual page 10

One complete rotation of the tuning knob results іп a 1KHz
frequency increase or decrease in 10Hz steps, 10KHz in
100Hz steps апа 100KHz іп 1KHz steps.
17. MODE/FREQUENCY DISPLAY
The frequency of the ІС-720 is displayed on a luminescent
display tube. Since the 1MHz and 1KHz decimal points are
displayed, the frequency can easily be read. The fre-
quencies indicated are the carrier frequencies of each mode
in AM, USB, LSB and CW. In the RTTY mode, the mark
frequency is displayed.
Remember, if you turn the RIT control on to change the
receive frequency and rotate the RIT 'control knob, the
frequency displayed will not change.
18. DIAL LOCK INDICATOR.
Lights when the Dial Lock is activated.
19. DIAL TUNING SPEED (TS) INDICATOR
Lights when tuning speed is selected.
20. RIT INDICATOR
Lights when the RIT is on.
21. CW-N (CW NARROW) INDICATOR
Lights when CW narrow is selected. The LED will light even
though the crystal filter option is not installed.
22. TRANSMIT INDICATOR
Lights when the transceiver is in the transmit mode.
23. FUNCTION KEY
Extends the functions of the CW and SSB Mode switches,
plus the VFO Equalizing Switch, by pussing this key switch.
24. MODE SELECT SWITCHES
Selects any one of four operating modes by simply pushing
the desired switch. Additionally, the CW and SSB switches
have dual functions.
CW: Push the button for normal CW operation.
CW Narrow: First push the Function button then the
CW button, this will select CW Narrow. This mode is
functional only when the optional narrow crystal filter
is installed.
SSB-N: For nomal SSB operation, Upper sideband for
10MHz band, and above, and Lower sideband for 9MHz
and below.
SSB-R: To reverse the above first push the Function
button and then the SSB button. |
AM Button: Selects the AM mode. (Note: When the
optional filter is installed the PBT can be used in the AM
mode.)
The RTTY button. Selects RTTY.
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25. VFO SWITCH
You can select either of the built-in VFOs with this switch.
it will also work in conjunction with the SIMP/DUP switch
in the following manner.
A. (Simplex) Selects the "А" VFO for both transmit and
receive.
A. (Duplex) Selects "А" VFO for receive апа "В" VFO
for transmit.
В. (Simplex) Selects the "В" VFO in both transmit and
receive.
В. (Duplex) Selects "В" VFO for receive апа "А" VFO
for transmit.
NOTE: Theset will not transmit іп the GENERAL COVER
Mode.
The frequencies on both VFOs will be retained in the CPU
memory if you switch from "A" to "В", or the reverse.
26. VFO A=B (Equalizing) SWITCH
This is a dual function switch. When the button alone is
pushed "В" VFO will switch to the same frequency as "A"
VFO. If the Function button is pushed first, then the
button, "А" VFO will switch to the same frequency as "В"
VFO.
27. RIT SWITCH
Push once for on; if off is desired push the switch again.
When the RIT is on the RIT LED will light. (Note: The
RIT will also pulse off when the main tuning knob is turned.)
28. AGC (AUTOMATIC GAIN CONTROL) SWITCH
For changing the time-constant of the AGC circuit. With
the switch in the AGC position (out) the AGC voltage is
released slowly for SSB reception., when the switch is in the
Fast position (in) the AGC voltage is released faster and is
better for stations that fade quickly in the CW mode.
29. NB (NOISE BLANKER) SWITCH
Specially designed for the IC-720 this noise blanker will
serve to lessen noise of a pulse type, the noise blanker is on
when the button is in.
30. ATT (ATTENUATION) SWITCH
When nearby signals interfere with reception, or make "5"
readings difficult push the switch in, this removes the RF
Amplifier from the receiving circuit, and an attenuator is
put into the circuit. For normal operation leave it in the
off (out) position.
31. METER SELECT SWITCH
Selects meter function in the transmit mode.
32. SIMPLEX/DUPLEX (TRANSEIVE/SPLIT)
Selects the relationship of the two VFO's. In the SIMPLEX
(out) position, one VFO is for both transmit and receive.
In the DUPLEX (in) position, one VFO is for transmit and
the other is for receive.