Icom IC-701 User manual

\LL SOLID STATE
__ TRANSCEIVER
METER
WRICOM Ait sous state
ON/OFF ON
RECEIVE VOX
a-+ O 1°) o
AF GAIN~-®> AF GAIN P.B.TUNE TRANSMIT ON ON

SECTION
SECTION
SECTION
SECTION
4-1
4-2
4-3
SECTION
5-1
5-2
5-3
5-4
5-5
SECTION
6-1
6-2
6-3
6-4
6-5
6-6
SECTION
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Fe2
7-3
ie
SECTION
SECTION
SECTION
SECTION
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SECTION | SPECIFICATIONS
GENERAL
Number of Semi-Conductors:
Transistors 128
FET 23
IC (Includes LS!1) 56
Diodes 265
Frequency Coverage:
1.8MHz ~ 2.0MHz
3.5MHz ~ 4.0MHz
7.0MHz ~ 7.5MHz
(7.3MHz~7.5MHz Receive Only)
14.0MHz~15.2MHz
(14.35MHz~15.2MHz Receive Only)
21.0MHz~21.5MHz
28.0MHz~30.0MHz (28.0MHz~29.7MHz Transmit
Range)
Frequency Control:
LSI based 100Hz step Digital PLL synthesizer.
Independent Transmit-Receive Frequency Available
on same band.
TRANSMITTER
DC Input Power:
SSB (A3J) 200 Watts
CW (Ai), RTTY (Fi) 200 Watts
Continuously Adjustable Output power 0~Max.
Emission Mode:
A3J SSB (Upper sideband and Lower sideband)
Al CW
Fi RTTY (Frequency Shift Keying)
Harmonic Output:
More than 40dB below peak power output
Spurious Output:
More than 60dB below peak power output
Carrier Suppression:
More than 40dB below peak power output
Unwanted Sideband:
More than 40dB down at 1000Hz AF input
Microphone:
Impedance 600 ohms
Input Level 10 millivolts typical
Dynamic or Electret Condenser Microphone
Frequency Readout:
6 digit LED 100Hz readout.
Frequency Stability:
Less than 500Hz after switch on 1 min to 60 mins, and
less than 100Hz after 1 hour. Less than 1KHz in the
range of—10°C to +60 °C.
Power Supply Requirements:
DC 13.6V +15% Negative ground Current drain
18 A max. (at 200W input)
AC power supply speaker console is available for AC
operation.
Antenna !mpedance:
50 ohms Unbalanced
Weight:
7.3Kg
Dimensions:
111mm x 241mm x 311mm (H x W x L)
RECEIVER
Receiving System:
Triple Conversion Superheterodyne with continuous
Bandwidth Control
Receiving Mode:
Ai, A3J (USB, LSB) Fi (Output FSK audio signal)
IF Frequencies:
Ist 9.0115MHz
2nd 10.75MHz
3rd 9.0115MHz
with continuous Bandwidth Control
Sensitivity:
Less than 0.25 microvolts for 10dB S+N/N
Selectivity:
SSB. RTTY +1.2KHz at —6dB
(Adjustable to +0.5KHz Min)
+2.0KHz at —60dB
CW +250Hz at —6dB
+700Hz at —60dB
CW-N +100Hz at —6dB
+500Hz at —60dB (with Audio Filter)
Spurious Response Rejection Ratio:
More than 60dB
Audio Output:
More than 1.5 Watts
Audio Output Impedance:
8 ohms
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SECTION 2 FEATURES
ALL. BAND, ALL MODE, ALL SOLID STATE
The IC-701 covers all the Amateur HF frequencies from 1.8MHz to 29.999.9MHz plus 15MHz WWV. It offers not only
SSB, but also CW and RTTY. All of the circuits in the IC-701, including the driver and final power stages are completely
solid state, and provide about 100 Watts output.
COMPUTER COMPATIBLE TUNING SYSTEM
The local oscillator circuit (VFO) employs a C-MOS LSI! for the PLL that has been custom-made on the basis of ICOM’s
advanced digital technology. The VFO circuit is a digital PLL circuit that controls frequency determination by pulses
produced by the tuning control. Unlike conventional PLLs, it controls the VCO by combining and dividing crystal oscillator
frequencies. Therefore, its stability is much higher than conventional VFOs. In addition, the pulse control system makes
it possible to set and change frequencies with external digital signals.
With a computer programmed and connected to the rear accessory socket, you can easily control frequencies, change bands,
scan, on the IC-701. This system will give you the maximum of performance and versatility.
DUAL DIGITAL VFO’S
The IC-701 contains two built-in digital VFO’s located in ICOM’s custom LSI, providing the ultimate in versitility.
DIGITAL READOUT AND FULL METERING
The
frequency
is
presented
in
bright
easy
to
read
LEDs,
with
no
backlash
or
waiting
time.
The
mulit-function
meter
shows
you
relative
signal
strength
in
receive,
power
output,
ALC,
SWR,
compression
level,
final
transistor
voltage
and
current.
All
the
important
information
you
need
to
know.
PASS BAND TUNING AND SPEECH PROCESSOR
The
IC-701
has
a
built-in
Pass
Band
Tuning
system
developed
by
ICOM
that
allows
you
to
continuously
adjust
the
pass
band
of
the
IF.
By
turning
the
control,
you
can
eliminate
interference
from
a
nearby
signal,
thus
providing
clear
reception.
It
can
also
be
used
as
a
tone
control.
During
transmit,
the
Pass
Band
Tuning
circuit
can
be
used
as
a
Speech
Processor
providing
increased
“talk
power”
for
outstanding
D
Xing.
OUTSTANDING PERFORMANCE
The RF amplifier circuit using MOS FETs, the Schottky barrier diode balanced mixer and other circuits provide excellent
Cross Modulation and Two-Signal Selectivity characteristics. The IC-701 has excellent sensitivity demanded especially for
mobile operation, high stability, and with two Crystal Filters having high shape factors, exceptional selectivity.
The
Same
Schottky
diode
mixer
is
used
in
the
transmitter,
and,
with
the
band
pass
filter
and
high
performance
K-Constant
two
stage
low-pass
filter,
ensures
transmission
of
pure
signals
with
very
low
spurious
emission.
ADDITIONAL CIRCUITS
The IC-701 has a built-in Noise Blanker, VOX, an Auto Dimmer for control of the readout and meter illumination, CW
Monitor, APC, SWR detector, and many other circuits for your convenience.
The IC-701 has everything you need to really enjoy HF operation, in an extremely compact, rugged transceiver.
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SECTION 3
INSTALLATION
BE SURE TO READ THE FOLLOWING INSTRUCTIONS BEFORE USE.
3-1 UNPACKING
Carefully remove your transceiver from the packing carton
and examine it for signs of shipping damage. Should any
be apparent, notify the delivering carrier or dealer im-
mediately, stating the full extent of the damage. It is
recommended you keep the shipping cartons. In the event
storage, moving, or reshipment becomes necessary they
will be handy. Accessory cables, plugs, etc., are packed
with the transceiver. Make sure you have not overlooked
anything.
1. Microphone (1C-SM2) .......... 0.0. e eee eee eee 1
2. External Speaker Plug... .. 2.0.0... cc ee eee wees 1
Oe SCV FIUG* oo tack ne ieee an tee seek e te ee oe tee 1
4. Scope Terminal Plug........... 0.0.02 eee eens 1
5. Transverter terminal Plug .............005 0 eee 1
6. Spare Fuse (20 Amp) ........... 000 ee eee eeee 2
7; DG, Power Cord’. oe adie Set ied yee ee es 1
8. Accessory Plug (24 Pin) ............02 0c eee 1
GO: Accessory Plug PINs - 3-4 ewiiwat- ie oa ek Sat es 24
10. Accessory Plug Boot ............ 0c cece eee eens 1
3-2 RECOMMENDATIONS FOR
INSTALLATION
1. Avoid placing the IC-701 in direct sunlight, high
temperature, dusty or humid places.
2. The left side of the unit, when facing it, functions
also as a heatsink. The temperature there will usually
become relatively warm during transmission. Any
equipment should be at least 1 inch (83cm) away from
the unit so as to provide good ventilation. Be sure that
nothing is on and just behind the rear PA heatsink to
ensure good ventilation. Also avoid places near outlets
of heaters, air conditioners etc.
3. Place the unit so that the controls and switches can
easily be handled and the frequency indication and
meter can easily be read.
4. For mobile installation, an optional mounting bracket
is available. Select the best location that can stand the
weight of the unit and that does not interfere with your
driving in any way.
5. Use the Ground Lug!
3-3 POWER SUPPLY
For AC operation, use the special power supply !C-701PS.
If you would like to use your car battery or any other DC
power supply, be sure that its output voltage is 12-15 Volts
and the current capacity is at least 20 Amps. The maximum
power consumption of the set during transmission runs
from 16-20 Amps, so keep that in mind if the unit is
installed in your automobile, and turn it on after you have
started the engine. Attention should also be paid to the
condition of the battery and electrical system.
The connection of the DC power cord supplied with the
1C-701 is done in the following way: First make sure that
the power switch of the unit is in the OFF position and
the T/R switch is in the receive position. Connect the cord
to the DC power supply with the RED lead to the positive
terminal and the BLACK lead to the negative terminal.
(Reverse connection will cause the protection circuit to
operate and blow the fuse.) Connect the DC plug to the
socket on the rear panel of the !C-701. Refer to the
drawing below.
a
seas
O
A
|
1C-701PS
:
pSeRR ER RESEREREESES AC POWER
OUTLET
For AC operation
BATTERY
or
De POWER SOURCE
DC POWER CORD
For DC operation
3-4 ANTENNA
Antennas play a very important role in radio communi-
cation. If the antenna is inferior, your transceiver cannot
give you the best performance. With a good antenna and
feeder cable having 50 ohm impedance, you should easily
get the desired matching and performance. Carefully install
a high performance antenna that suits the frequency
band(s) you wish to operate on and place it as high as
possible. Be especially careful of the condition of the
connectors as loose connections will deteriorate the per-
formance. Be sure to connect the ground terminal of a
whip antenna, if used, to the body of your car.
As the output is quite high, avoid connecting the antenna
connector to open lines and do not transmit under
mismatched conditions. Otherwise the final stage could be
overloaded and cause a malfunction of the unit.
—-3-
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3-5 GROUND
In order to prevent electrical shocks, TVI, BC! and other
problems, be sure to connect a heavy wire ground, as
short as possible, from a good earth point to the ground
terminal on the rear panel.
3-6 MICROPHONE
The microphone supplied with the IC-701 is the IC-SM2
which contains a pre-amplifier. It’s circuit diagram is shown
below. The IC-SM2 is an Electret Condenser type
microphone.
Schematic diagram of IC-SM2
R7 200M
(2)
° 3 3 7] ° o
°
TR1, TR2: 2SC536 or equivalent
A sensitivity contro! is installed on the bottom side of the
mic stand. By turning it in the “’H” or “L” direction, the
sensitivity will increase or decrease respectively. Adjust the
control so as to get the proper sensitivity considering the
distance to the mic, the loudness of your voice and the
environmental conditions. The wind screen not only
prevents background noise due to wind, but also protects
the mic. Unless required, do not remove the screen from
the mic. In order to operate the microphone, connect its
plug to the mic socket on the IC-701. To transmit, press
the PTT switch downward. When it is released, the IC-701
will return to the receive condition. For a long transmis-
sion, pull the PTT switch back while pressing it down until
the switch is locked and it will remain in that position until
it is pushed forward and released.
LOCK RELEASE
Key Wiring Diagram
If you would like to use a different microphone in your
car, an optional hand held dynamic microphone is available.
If other types of microphones are used, be sure their
impedance is between 500-600 ohms, and connect a 4 pin
plug in the manner shown.
Microphone plug exploded view
Microphone connection
Microphone
(cord side view)
3-7 CW KEY
When operating CW, connect the Key to the Key Jack with
the plug supplied. The connection of the plug is shown
below.
If the terminals have polarity, be sure to make the correct
connection.
Note
that
the
keyed
voltage
when
switching
with semiconductors or relays with resistors in the circuit,
should be adjusted to be below 0.4 Volts!
3-8 RTTY
When operating RTTY, connect the ACC socket pins 8
(ground)
and
9
to
your
tele-typewriter
through
a
high
speed
relay or a level converter to TTL level, and the tones for
your
terminal
unit
will
be
available
from
pin
4.
For
details,
refer
to
“How
to
use
RTTY”,
and
“Transmit
and
Receive”’
sections in this manual.

3-9 EXTERNAL SPEAKER
The IC-701 contains an internal speaker, and is also
designed so that it can drive an external speaker from the
external (EXT) speaker jack on the rear panel. Be sure the
impedance of the external speaker is 8 ohms, and remember
that with the external speaker connected, the internal
speaker is disabled.
3-10 HEADPHONES
Any good headphone set, including stereo type, that have
4-16 ohms impedance can be used. With the plug inserted
halfway into the PHONES jack, both the headphone and
speaker will operate. This is convenient when others wish
to listen in on the station, or you wish to record contacts
using a tape recorder connected to the headphone jack.
With a stereo headphone set inserted this way, however,
the headphone will lose the sound on one side. With the
plug inserted completely, only the headphone works.
3-11 POWER SUPPLY
It is highly recommended that you use the [C-701PS power
supply for base operation. If you wish to use another
power source, make sure that it meets the voltage, current,
and regulation requirements. Pay particular attention to
the overvoltage protection as a runaway regulator can
destroy the IC-701. Make certain that more than 18 Volts
does not get applied to the unit. When the power switch
is in the ON position, do not connect the power cord,
antenna, external speaker, Accessory plug, or the mi-
crophone to avoid possible trouble. Be sure not to transmit
with the antenna disconnected. If the fuse blows, replace
it with a new 20 Amp fuse after fixing the cause. Avoid
turning
the
power
switch
ON
and
OFF
repeatedly
over
a
short time. Frequent repetitions may cause the frequency
indicator to display the wrong frequencies. If such a
malfunction should occur, turn OFF the switch and a few
seconds later turn it ON again.
3-12 CAUTIONS
As the unit has already been closely adjusted with highly
sophisticated measuring instruments, never tamper with
the turnable resistors, coils, trimmers, etc.
IN THE PLL UNIT, THE HEART OF THE TRAN-
SCEIVER, A C-MOS LSI IS INCORPORATED. IF THE
SEAL IS BROKEN WHEN A FAILURE OCCURS WITHIN
THE TERMS OF THE GUARANTEE, THE REPAIR
MAY BE AT THE USERS EXPENSE, SO DO NOT
ATTEMPT TO OPEN THE PLL CASE!
C-MOS is also used in the digital driver unit as well as the
PLL. C-MOS ICs are very susceptible to excessive static
charges and over current and care must be used when
handling them. Therefore, avoid touching the driver
unit and the nearby circuitry unless absolutely necessary.
When it is necessary to check the circuitry, observe the
following points.
Ground all measuring instruments, the soldering iron, and
other tools. Do not connect or disconnect the C-MOS IC
from its socket, or solder it when the power is ON. Do
not apply voltage of less than —0.5 or more than +5 Volts
to the input terminals of the IC. DO NOT MEASURE
WITH AN OHMMETER.
3-13 COOLING FAN
The rear of the PA unit is designed to achieve effective
natural cooling. But with 200 Watts input, the final stage
circuit produces quite a bit of heat and its temperature may
rise during a very long, continuous transmission. If the
temperature becomes high enough, the built-in cooling fan
will start to spin. The fan is connected to the temperature
monitoring circuit which detects the temperature of the
final stage transistors. The operation of this fan is as
follows:
1. The fan does not work during all reception.
2. During transmission, it does not work if the detected
temperature is below a certain level.
3. When the temperature exceeds that level during a
transmission, the fan will start to move air across the
heatsink to cool it.
4. If the temperature of the final stage transistors rises to
the danger point, the fan will turn at a much higher
speed and frequency display will start to flash.
THIS MEANS STOP TRANSMITTING!
1, 2 and 3 are normal conditions. 4 is abnormal. If the
meter and display start to flash, stop transmitting and
check for the cause of the excess heat. This could be
antenna mismatch, environmental problems, etc., but be
sure to rectify the problem before beginning to operate
again.
—5—
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SECTION
4
OPERATING
CONTROLS
4-1 FRONT PANEL
@ DIAL LOCK INDICATOR LED
@ FREQUENCY DISPLAY
@ DIAL TS INDICATOR LED
@ TRANSMIT INDICATOR LED
@ MULTI-FUNCTION METER
78 5 ALC Po
ef ee COMP 4.4 “io
35 Sm!
> aT
@
BAND
SWITCH
en
mr
(.
@®
METER
SELECT
whe
SWITCH
rd
@ POWER SWITCH
® PHONES JACK—33
® MIC CONNECTORS
/ 4
WB. TINE /’
fj i
@ COMP (SPEECH
PROCESSOR)
CONTROL
@® MIC GAIN CONTROL
@ AF GAIN CONTROL
@ RF GAIN CONTROL
@ MODE SELECT
SWITCH
(PASS BAND TUNING
( VFO SWITCH
@ RIT CONTROL
1. BAND SWITCH
The BAND SELECT SWITCH is a 7 position rotary switch
used for selecting one of the 6 Amateur bands covered by
the IC-701 with a 7th position for external control.
The selectable bands are 1.8MHz, 3.5MHz, 7MHz, 14MHz,
21MHz and 28MHz. In the EXT position, the band can
be selected remotely. However, the switch should not be
put in the EXT position without having the remote control
connected. This will cause the rotary switch to rotate
continuously and may cause excessive wear or damage.
2. MULTI-FUNCTION METER
With the {C-701 in the receive mode, this meter acts as an
S meter regardless of the position of the meter select
—-6-—-
11c-70O8
8 RATB -
. Lo SBR pit NB oRaC
ee,
@ DIAL LOCK BUTTON
@ TUNING CONTROL
KNOB
@ TUNING SPEED BUTTON
12 AGC SWITCH
@ ATTENUATOR SWITCH
(® NOISE BLANKER SWITCH
(9 VOX SWITCH
1) RIT SWITCH
@ TRANSMIT/RECEIVE SWITCH
switch. Signal strength is indicated on a scale of $1-S9
and $9+20dB to S9+60dB.
In the transmit mode, the meter has 5 functions as outlined
below which are selected by the meter select switch.
3. METER SELECT SWITCH
In the transmit mode the meter has 5 functions.
1. Ve Indicates the collector voltage of the final
transistors.
2. Ic Indicates the collector current of the final
transistors.
3. Po Indicates the relative output power. SWR can
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be measured by placing the SWR/SWR SET
switch in the SWR position. (This switch is
located under the access cover on the top of
the IC-701.
4. ALC In this position, the meter begins to function
when the RF output power reaches a certain
level.
5. COMP Indicates the compression level when the speech
processor is in use.
4. POWER SWITCH
The POWER SWITCH is a push-lock type switch which
controls the input DC power to the IC-701. When the
external AC power supply (IC-701PS) is used, the switch
also acts as the AC power supply switch. When the switch
is pushed in and locked, power is supplied to the set. When
the switch is pushed again and released, power is cut to all
circuits except the PA unit.
5, PHONE JACK
This jack accepts a standard 1/4 inch headphone plug for
a 4-16 ohm headphone set. Stereo headphones can be
used without modification.
6. MIC CONNECTOR
Connect the supplied microphone or optional microphone
to this jack. If you wish to use a different microphone
than the IC-SM2, refer to the drawing on page 4. Mic-
rophone impedance should be 500-600 ohms.
7. COMP (SPEECH PROCESSOR) CONTROL
The IC-701 contains a built-in RF speech processor which
is turned ON by turning the center knob clockwise from
the OFF position (a click will be heard). In the ON position
it works as the RF drive control as explained below. In
the CW and RTTY modes, it works as the output level
control of the IC-701. When RF speech processor
operation is not desired, the COMP control should be
turned completely counter-clockwise and clicked OFF.
8. MIC GAIN CONTROL
Adjusts the level of modulation according to the input of
the microphone. Clockwise rotation increases microphone
gain. As the input will vary with different microphones
and different voices, the knob should be turned until the
MULTI-FUNCTION METER needle, in the ALC mode,
starts to move slightly within the ALC zone. In the SSB
mode, with the RF speech processor in use, the MIC
GAIN CONTROL sets the clipping limits, while the COMP
control sets the RF drive level up to the maximum power
level where ALC begins at the saturation point of the
amplifiers.
9. AF GAIN CONTROL
Controls the audio output level in the receive mode.
Clockwise rotation increases audio output.
10. RF GAIN CONTROL
Controls the gain of the RF section in the receive mode.
Clockwise rotation gives the maximum gain. As the
control is rotated counter-clockwise, the needle of the
MULTI-FUNCTION METER rises, and only signals stronger
than the level indicated by the needle will be heard.
11. MODE SELECT SWITCH
This switch selects the mode of operation for both
transmit and receive.
USB Upper Sideband, mainly for 14, 21 and 28MHz
bands.
LSB Lower Sideband, mainly for 1.8, 3.5 and 7MHz
bands.
CW Continuous Wave, for CW operation on all bands.
~CW-N Narrow CW. The audio band-pass filter is auto-
matically turned ON in this position to improve
selectivity when receiving.
RTTY Radio Teletype. For use on all available bands.
12. P. B. TUNE (PASS BAND TUNING) CONTROL
This control allows continuous tuning of the pass band
selectivity moving the edge of the filter up to 1.5KHz from
either the upper or lower side in SSB and RTTY. This not
only improves selectivity, but also can improve the audio
quality. The normal position is in the center (12:00
o'clock) position and is 2.4KHz wide in SSB.
13. VFO SWITCH
With this switch you can select the VFO you want to
operate from two separate VFO’s that are built-in to the
IC-701. It also selects the relationship of the two VFO’s.
The switch performs the following operations according
to its position.
* A: Selects ““A’’ VFO for both transmit and receive.
* B: Selects ‘“B’’ VFO for both transmit and receive.
* RA-TB : Selects ‘““A’’ VFO for receive and ‘B’’ VFO for
transmit.
* RB-TA: Selects ‘‘B’’ VFO for receive and “A’’ VFO
for transmit.
In addition, when the VFO is switched from “‘A’’ VFO to
“B’ VEO, the frequency indicated on the frequency
display just prior to switching goes into a memory inside
the LSI. Thus even if ‘“B’’ VFO is being used, switching
to “A” again will enable you to operate at the initial
frequency. Switching from “‘B” to “A” results in the
same operation. However, if switching is done with the
BAND SWITCH (or external control), the VFO frequency
displayed will disappear and the lower end frequency of
the band selected will be displayed. If you wish to operate
on the frequency that was memorized in the VFO that
was not used when switching bands, simply return to the
original band and then to the other VFO and the initiall
memorized frequency will appear.
more detail later in this manual.
This is explained in
14. RIT CONTROL
Shifts the receiver frequency +800Hz either side of the
transmit frequency. When the RIT is ON, the RIT LED is
illuminated. The LED also represents the ‘‘0’’ position.
Rotating the control to the (+) side raises the receiver
frequency, and rotating to the (—) side lowers the receiver
frequency. With the RIT ON, if the tuning knob @j) is
moved one increment, the RIT circuit is automatically
pulsed OFF. Therefore it is not necessary to manually turn
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OFF the RIT when changing operating frequency. The
frequency shift by tuning the RIT Control is not indicated
on the frequency display.
15. RIT SWITCH
This is a spring-loaded switch for the RIT control. To
turn ON the RIT, push down once. If OFF is desired, push
down again. When the RIT is ON the LED above the RIT
control knob is lit. This also indicates the center position
of the RIT control. With the RIT circuit OFF the LED
is also OFF. Also if the RIT is ON and the Tuning Knob
is rotated one increment it will pulse the RIT OFF unless
the internal jumper has been changed.
16. NB (NOISE BLANKER) SWITCH
When pulse type noise such as automobile ignition noise is
present, set this switch to the ON (down) position. The
noise will be reduced to provide comfortable reception.
17. AGC (AUTOMATIC GAIN CONTROL) SWITCH
With this switch you can change the time constant on the
AGC circuit. With the switch in the AGC (up) position,
the circuit operates as a ‘“hang’’ AGC and maintains the
AGC voltage for a specific time, thus it is suitable for SSB
reception. With the switch in the FAST (down) position,
the circuit is OFF, and AGC is suitable for stations suffering
from fast fading or operating in the CW mode.
18. TRANSMIT/RECEIVE (T/R) SWITCH
This switch is for manually switching from transmit to
receive and vice versa. Set the switch to RECEIVE (up)
and the !C-701 is in the receive mode. Set the switch to
TRANSMIT (down) and it switches to transmit. When
switching with the PTT switch on the microphone or with
the VOX switch set to ON the T/R switch must be in the
RECEIVE position.
19. VOX SWITCH
This switches the VOX circuit ON and OFF. When it is
in the ON (down) position, in SSB, T/R switching is
accomplished by means of a voice signal. !n CW operation,
semi-break-in switching by means of keying is possible.
20. ATT (ATTENUATOR) SWITCH
Turn the ATT switch ON (down) when strong nearby
signals disturb signal reception or make “’S” readings
difficult. in the ON position, a 10dB attenuator is inserted
into the receiving antenna circuit, reducing interfering
signals and giving more stable reception. In normal
operation the ATT switch is left in the OFF (up) position.
21. TUNING CONTROL KNOB
Rotating the TUNING CONTROL KNOB clockwise in-
creases the frequency, while rotating it counter-clockwise
decreases the frequency. The frequency is changed in
100Hz steps which correspond to the smaller vernier
marks on the knob. The larger marks represent 1KHz
steps. One complete rotation of the tuning knob results in
a 5KHz frequency increase or decrease in 100Hz steps
exactly as shown by the small vernier marks.
22. TUNING SPEED BUTTON
Pushing the TUNING SPEED BUTTON will illuminate the
DIAL FAST display LED, and the small vernier marks on
the tuning knob are changed to correspond to 10KHz steps.
At the same time, the 1KHz and 100Hz digits are cleared
on the display to show ‘0.0’... When the Tuning Speed
Button is depressed again, the dial fast display LED goes
OFF and the small vernier marks will again correspond to
100Hz steps. This button will allow you to quickly QSY
over a great frequency range.
23. DIAL LOCK BUTTON
After the IC-701 is set to a certain frequency for rag
chewing, mobile operation, etc., pushing the DIAL LOCK
BUTTON will illuminate the DIAL LOCK display LED
and the VFO is electronically locked at the displayed
frequency, thus inactivating the operation of the tuning
knob. To change frequency, the dial lock must first be
disengaged by pushing the dial lock button again. The dial
lock display LED will go OFF and the frequency will
change with the direction of the tuning knob rotation.
Turning the power OFF will release the dial lock and clear
the displayed frequency.
24. FREQUENCY DISPLAY
The frequency of the IC-701 is displayed on 7 segment
LEDs. 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 USB, LSB and CW. In the RTTY mode, the space
frequency is displayed. Since the local oscillation frequency
is shifted in accordance with modes, no tuning will be
required if you change modes. 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.
25. TRANSMIT INDICATOR LED
When your set is in the transmit mode, this LED is lit.
26. DIAL TUNING SPEED INDICATOR LED
illuminates when the TUNING SPEED BUTTON is pressed
to set the dial to fast tuning.
27. DIAL LOCK INDICATOR LED
illuminates when the DIAL LOCK BUTTON is pressed
to lock the dial.
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4-2 CONTROLS UNDER ACCESS COVER
@ DIM SWITCH
@RTTY SHIFT SWITCH
@ SWR SWITCH
6) CW MONITOR CONTROL
2 SWR SET CONTROL
@ FREQUENCY SET CONTROL
DIM GAIN CONTROL
28. DIM SWITCH
When this switch is set to DIM, the luminosity of the
frequency display and the meter automatically decreases
when the ambient level is reduced below a set level.
Therefore, under dim lighting such as at night, it decreases
the luminosity to a lower level for easy indicator reading.
When the switch is at the OFF position, the dimmer
function is disabled.
29. RTTY SHIFT SWITCH
This switch shifts transmit frequency and shift spacing.
Normally the shift is 170Hz, but in some cases 850Hz is
still used. Set the switch for the desired shift.
30. SWR SWITCH
When measuring SWR, calibration SET and SWR reading
functions are selected with this switch. Remember, at the
factory, the switch is in the SET position and fixed in
place with a plastic screw to prevent it from switching to
SWR. Remove the screw before attempting to read SWR!
SWR must be read only in the Po meter position.
31. CW MONITOR (MONI) CONTROL
This control adjusts the audio volume of the side tone
(monitor) audio during CW transmit operation. Adjust it
to your desired level for easy listening.
32. SWR SET CONTROL
This control calibrates the meter needle to the Po SET
position when you want to determine the value of SWR.
The meter must be in the Po position and the set must be
transmitting a carrier.
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6) VOX DELAY CONTROL
8 ANTI VOX CONTROL
6) CW DELAY CONTROL
6) VOX GAIN CONTROL
33. FREQUENCY SET CONTROL
This control is for fine adjustment of the VXO section
frequency of the PLL unit, which is the local oscillator
frequency. Do not turn it unless you want to change the
frequency.
34. VOX GAIN CONTROL
This control adjusts input signal level via the microphone
to the VOX circuit. For VOX operation in SSB, adjust the
control so that the VOX circuit will operate with normal
speech.
35. CW DELAY (CW time delay constant) CONTROL
In Semi-break-in CW operation, this controls the TX/RX
switchover time delay. Adjust it to suit your keying speed.
36. ANTI VOX CONTROL
In VOX (SSB) operation, the VOX circuit may be operated
by sound from the speaker causing a switch to transmit.
This trouble can be prevented by adjusting the input level
of the ANTI VOX circuit with this contro! along with the
VOX gain control so that the VOX circuit only operates
from the operator’s voice, not by sound from the speaker.
37. VOX DELAY (VOX time constant) CONTROL
This controls the TX to RX switching time. Adjust it so
TX to RX switching will not occur during short pauses in
normal speech.
38. DIM GAIN (dimmer circuit) CONTROL
The threshold for the functioning of the dimmer circuit
can be adjusted by turning the DIM GAIN CONTROL.
Turning the control counter-clockwise will lower the
operation threshold of the circuit.
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4-3 REAR PANEL CONNECTIONS
6) RECEIVER INPUT TERMINAL
@ RECEIVER ANTENNA
OUTPUT TERMINAL
@ANTTENA CONNECTOR
@EXTERNAL SPEAKER JACK
@KEY JACK
@FUSE HOLDER
@ GROUND TERMINAL
39. RECEIVER INPUT TERMINAL
This is an input terminal which is connected directly to
the receiver.
40. RECEIVER ANTENNA OUTPUT TERMINAL
This is a terminal to which received signals from the
~ antenna connector are conducted after the signal passes
through the transmit/receive antenna switching circuit.
Usually the receiver IN and OUT terminals are jumpered.
The receiver antenna output terminal is usually used when
another receiver is used or a pre-amplifier is connected to
the IC-701.
41. ANTENNA (ANT) CONNECTOR
This is used to connect the antenna to the set. Its
impedance is 50 ohms and connects with a PL 259
connector.
42. EXTERNAL SPEAKER JACK
When an external speaker is used, connect it to this jack.
Use a speaker with an impedance of 8 ohms. When the
external speaker is connected, the built-in speaker does
not function.
43. KEY JACK
For CW operation, connect the key here. For electronic
keying the terminal voltage must be less than 0.4V DC.
44. FUSE HOLDER
This holds the fuse for the DC power circuit. If the fuse
is blown, replace it with.a new 20 Amp fuse after checking
the cause. Open the fuse holder with a Phillips head driver.
4)SCOPE TERMINAL
@TRANSVERTER
TERMINAL
@ ACCESSORY SOCKET
POWER SOCKET
45. GROUND TERMINAL
To prevent electrical shock, TVI, BCI and other problems,
be sure to ground the equipment through the GROUND
TERMINAL. For best results use as heavy a gauge wire or
strap as possible and make the connection as short as
possible, even in mobile installations.
46. POWER SOCKET
Connect the DC power cord or cable from the !C-701PS
or suitable DC source to this connector.
47. ACC (ACCESSORY) SOCKET
Accessories and controls can be used with the IC-701 and
connected to the ACC socket on the rear panel. NOTE:
Pins 14-24 are terminals for digital control and are con-
nected to the input terminal of the C-MOS IC. By no
means apply any voltage not within the range of —0.5 to
+5 Volts. For details, refer to page 20.
48. X-VERTER (TRANSVERTER) TERMINAL
VHF and UHF operation using a suitable transverter with
the IC-701 is possible. This terminal is for Transverter
connection. The output is a few milliwatts. Refer to the
tranverters instruction for recommended hookup.
49. SCOPE TERMINAL
This terminal brings out the 9.011MHz IF signal from the
mixer in the receiver. Not only observation of the received
signal, but also of signals of a the selected band width are
possible by using a panadaptor or panascope.
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SECTION
5
OPERATING
INSTRUCTIONS
5-1 HOW TO TUNE
The following instructions are for tuning in any mode.
Please read carefully and understand fully before turning
on your unit. Proper tuning is necessary for optimum
operation.
5-1-1 TUNING KNOB
The transmit or receive frequency is displayed on 7 segment
LEDs down to 100Hz digits. Rotating the tuning knob
clockwise increases the frequency, while turning counter-
clockwise decreases the frequency in 100Hz steps. The
smaller vernier marks on the knob represent 100Hz and the
larger marks represent 1KHz. One complete rotation of
the tuning knob results in a 5KHz frequency increase or
decrease. When you receive your set, calibration of the
tuning knob may be desirable, as the large increments may
not correspond exactly to a change of 1KHz displayed on
the LEDs. Exact calibration is not necessary as the
displayed LED frequency will always be correct, but you
may calibrate the scale on the tuning knob for use as an
analog type frequency display. To calibrate, set a large
increment on the tuning scale to line up with the indicator
arrow directly above the scale and then turn ON the power.
To calibrate the scale during operation, if desired, set a
large increment on the tuning scale to line up with the
indicator arrow and then push the tuning speed button
TWICE. By doing so, the 1KHz and 100Hz digits are
cleared on the display to show “0.0”.
The tuning knob scale may require recalibration if you:
1. Turn the knob while the frequency is locked by use
of the Dial Lock Button.
2. Use the tuning speed button when a large increment is
not lined up with the indicator.
3. Turn the knob beyond the band edge.
If the knob is too loose or too stiff for comforatble use,
you can adjust the torque by tightening or loosening the
brake adjustment screw accessable from underneath the set.
Brake adjustment screw
Brake Adjustment
The following instructions should be used to adjust the
tension of the Tuning Knob.
1. Remove the bottom cover of the IC-701.
2. The Tuning knob tension will become tighter by turning
the brake adjustment screw clockwise, and will become
looser by turning the screw counterclockwise.
3. While performing this adjustment, the Tuning knob must
be turned continuously as the screw is adjusted in order
to set the tension for a comfortable touch.
4. After the adjustment has been made, replace the bottom
cover.
On all but the 28MHz band, the displayed frequency will
not go beyond the highest band edge even by turning the
tuning knob clockwise, or beyond the lowest band edge by
turning the knob counter-clockwise. On the 28MHz band,
since this band width is much wider than the others, the
IC-701 provides “‘automatic revert’’ for operating con-
venience. When the frequency display shows 29.999.9MHz
and the tuning knob is turned clockwise, the displayed
frequency jumps down to 28.000.0MHz and continues up
from there. Likewise, by continuing to turn counter-clock-
wise beyond the bottom edge of the band, the frequency
jumps up from 28.000.0MHz to 29.999.9MHz and goes
down from that point.
The displayed frequency shows the carrier frequency in the
USB, LSB and CW modes, and the SPACE frequency in the
RTTY mode. Therefore recalibration of the frequency is
unnecessary when the mode is changed.
5-1-2 DIAL LOCK BUTTON
After the IC-701 is set at a certain frequency for rag chew-
ing, mobile operation, etc., pushing the Dial Lock button
will illuminate the Dial Lock LED and the VFO is locked at
the displayed frequency, thus inactivating the operation of
the tuning knob. To change the frequency, the Dial Lock
must first be disengaged by pushing the dial lock button
again. The Dial Lock display LED will go OFF, and the
frequency will change with the direction of the tuning Knob
rotation. Turning OFF the power will release the Dial Lock
and clear the displayed frequency.
5-1-3 TUNING SPEED BUTTON
Pushing the Tuning Speed Button will illuminate the dial
fast LED and the small vernier marks on the Tuning Knob
is changed to correspond to 10KHz steps. At the same time,
the 1KHz and 100Hz digits are cleared on the display to
show ‘0.0’... When the Tuning Speed Button is depressed
again, the dial fast display LED goes OFF and the small
vernier marks will again correspond to 100Hz steps. This
button will allow you to quickly OSY over a great
frequency range.
5-1-4 VFO SELECT SWITCH
The LSI in the IC-701 contains two ‘‘VFO’s” for both
receiving and transmitting. The VFO’s are labeled “A”.
VFO and “‘B” VFO and are selectable with the VFO Select
Switch. This dual VFO system gives the IC-701 many very
convenient features. Please read this section very carefully
and perform the operation several times until you are
comfortable with the system.
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“1. “A” VEO is for both transmitting and receiving and is
selected by placing the VFO Select switch in the “A”
position. The transmit and receive frequency will be
controlled by “A’’ VFO, displayed on the LED fre-
quency readout, and stored in “A" memory.
2. ““B’ VEO is for both transmitting and receiving and is
selected by placing the VFO Select switch in the “B”’
position. The transmit and receive frequency will be
controlled by “‘B’’ VFO, displayed on the LED fre-
quency readout, and stored in ‘“B’’ memory.
3. RA-TB: The receive frequency is controlled by “A”
VFO and the transmit frequency is controlled by “B”’
VFO. Both frequencies are stored in their respective
memories, and displayed during their respective ope-
ration times (““A’” frequency during receive, and “B”’
frequency during transmit).
4. RB-TA: The receive frequency is controlled by “’B”
VFO and the transmit frequency is controlled by “A”
VFO, the reverse of the above. Again, both frequencies
are stored in their respective memories, and displayed
during their respective operation times (this time “B”’
frequency during receive and ‘A’ frequency during
transmit).
When the !IC-701 is first turned ON, the frequency displayed
on the LED readout is the lowest frequency limit of the
band selected by the band switch.
FOR EXAMPLE:
lf the band switch is set to the 7MHz band, when the set
is turned ON, 7.000.0 will be displayed on the LED readout.
This will occur whether the VFO switch is in either the “A”’
or “B’ or combination VFO position. Rotating the tuning
knob clockwise will increase the frequency in 100Hz steps.
Rotating the tuning knob counter-clockwise will decrease
the frequency in 100Hz steps. Note: Rotating the knob
counter-clockwise immediately after applying power will
not lower the frequency as it is already at the lowest limit.
Switching from one VEO to the other VFO does not clear
the first VFO. The frequency is retained in the VFO’s
memory.
EXAMPLE
lf 14.125.0MHz is set with ““A’’ VFO, and the VFO switch
is set to ““B’’ VFO, the frequency LED readout will show
“B’’ VEQO’s frequency, but 14.125.0MHz is still stored in
“A” VEQ’s memory. Returning the VFO switch to “A”
VFO position, and 14.125.0 will be displayed on the
readout. Accordingly, if the switch is placed in the “’B”
VFO position, the frequency that was set with the “‘B”’
VFO will appear. This allows you to set a certain frequency
with one VFO, work up and down the band with the other
VFO, and periodically check the set frequency simply by
switching between “A” and “B” VFO. It also allows you
to search for aclear frequency with one VFO, while keeping
your operating frequency on the other VFO. When you
have found a clear frequency, switch back to your operating
frequency, inform the station you are in contact with of
the new frequency, and switch back. It’s that simple!
The 1C-701 will perform this operation even on two dif-
ferent bands. A frequency is set in either “A” or “B’’ VFO
on one band, the VFO switch is set to the other VFO, and
the band switch set to any other band you wish to work.
When you want to go back to the set frequency, first return
to the original band and then to the original VFO and
you’re back on the set frequency.
FOR EXAMPLE
Set “A” VFO to 14.255.0MHz. Set the VFO switch to
“B’’ VFO. Switch to the 21MHz band. The frequency
readout will read 21.000.0MHz. Operate anywhere you
wish with “B’ VFO. When you want to return to
14.255.0MHz, first switch back to the 14MHz band. Then
switch to “‘A’’ VFO and the frequency readout wil! show
14.255.0MHz.
When recalling a memorized frequency be sure to turn OF F
the dial fast circuit. If the circuit is not turned OFF, the
memorized frequency’s 1KHz and 100Hz digits will both
revert to “0”.
RA-TB/RB-TA
These positions will allow you to operate split transmit/
receive frequencies on the same band.
EXAMPLE:
Set “A” VFO to 14.350.0MHz and “‘B” VFO to 14.255.0
MHz. Then set the VFO select switch to the RA-TB
position. 14.350MHz will shown on the readout during
receive (“A’ VFO) and 14.255.0MHz during transmit
(“B’ VFO). You are now receiving on 14.350.0MHz and
transmitting on 14.255.0MHz.
Setting the VFO select switch to RB-TA re rses the above.
Changing bands in these modes resets both “A” and ‘‘B”’
VFO to the lowest band limit.
5-1-5 RIT (RECEIVER INCREMEMTAL TUNING)
By using the RIT circuit, you can shift the receive fre-
quency +800Hz either side of the transmit frequency
without moving the transmit frequency itself. Therefore, |
when you get a call slightly off frequency, or when the
other station’s frequency has shifted, you can tune in the
frequency without disturbing the transmitting frequency.
By pushing the RIT switch down once (it’s a spring loaded
switch) the RIT circuit is turned ON and the RIT LED is lit.
The receive frequency is shifted with the RIT knob.
When the RIT knob is in the “0” position, the transmitting
and receiving frequencies are the same. Rotating the
control to the (+) side raises the receiving frequency, and
rotating to the (—) side lowers the frequency. To turn OFF
the
RIT
control,
again
push
on
the
RIT
switch
and
the
RIT LED will go OFF. When the RIT circuit is OFF, the
transmit and receive frequencies are the same regardless of
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the setting of the RIT contro! knob.
When the RIT circuit is ON, if the tuning knob is moved by
one increment, the RIT circuit is automatically pulsed OFF.
However, this function can be eliminated by changing the
connecting pins in the driver unit as shown below, in
case you would like the RIT to remain operational when
you turn the tuning knob. Or, by continuously depressing
the RIT switch with your finger while turning the tuning
knob, the RIT circuit will remain operational while tuning.
Other things to remember are: The RIT circuit is ope-
rational when the frequency is locked with the dial lock
button. The frequency shifted by turning the RIT control
is not indicated on the frequency display. When the
transmitting and receiving frequencies differ by more than
800Hz, use “A” and “’B’’ VFQs as outlined previously. »
5-2 SSB OPERATION
5-2-1 RECEIVING:
After connecting an antenna, microphone, etc., set knobs
and switches as follows.
POWER SWITCH OFF
T/R SWITCH RECEIVE (UP)
VOX SWITCH OFF (UP)
ATT SWITCH OFF (UP)
AGC SWITCH SLOW (UP)
NOISE BLANKER (NB) SWITCH OFF (UP)
MODE SELECT SWITCH USB or LSB
VFO SWITCH
BAND SELECT SWITCH
AF GAIN CONTROL
RF GAIN CONTROL
P.B. TUNE CONTROL
RIT CONTROL
“AO or "BY"
Desired Band
Completely Counter-clockwise
Completely Clockwise
Center (12 o'clock) position
Center (12 o’clock) position
The other knobs are unrelated to receiving and need not
be set at this time.
In SSB operation there is both an USB (upper side band)
and an LSB (lower side band). LSB is usually used on the
1.8, 3.5 and 7MHz bands, while USB is usually used on the
14, 21 and 28MHz bands. Select the mode according to
the band in which you wish to operate.
Now turn ON the power switch. The meter lamp will be
illuminated and the lowest frequency of the selected band
will be shown on the LED readout. Slowly turn the AF
gain contro! clockwise to a comfortable level. Rotate the
tuning knob until a signal is received. The multi-function
meter needle will move according to the signal strength, so
tune for the highest possible meter reading and the clearest
audio. If you cannot get a clear signal, you may be receiv-
ing in the opposite sideband. {f so, change the mode switch
to the proper sideband.
The VFOs in the IC-701 change in 100Hz steps. Therefore
the maximum possible difference in your receiving fre-
quency and the received signal frequency is 50Hz. However,
for normal voice signal reception, a difference of 50Hz is
negligible and indeed may be hard to distinguish. Since the
frequency is changed in 100Hz steps with the IC-701, as
opposed to continuous variable frequency systems, tuning
is simplified and more accurate.
5-2-2 NB (NOISE BLANKER)
Turn the noise blanker ON (down) when there is pulse type
noise, such as ignition noise from automobile motors.
Noise will be suppressed and even weak signals will be
received comfortably. The noise blanker may not work as
effectively when there is a strong signal on a nearby fre-
quency or when there is continuous (not pulse type) noise.
5-2-3 AGC (AUTOMATIC GAIN CONTROL)
The IC-701 has a ‘‘hang’’ AGC system which holds the peak
voltage of rectified AF signals from the detector circuit for
a certain period. Therefore, during the pauses in normal
speech of the received signal, uncomfortable noises will not
be heard. The multi-function meter indicates the peak
value for a certain period, facilitating reading of the meter
“S" function.
For normal SSB reception, set the AGC switch in the UP
(slow) position. Set the AGC switch in the FAST (down)
position, when tuning or receiving signals with short interval
fading. When in the FAST position, the hang AGC circuit is
turned OFF and the time constant is shortened. Use the
FAST position for RTTY reception.
5-2-4 ATT (ATTENUATOR) SWITCH
Turn the ATT switch ON (down) when strong nearby
signals disturb signal reception or make “S’’ reading dif-
ficult. In the ON position a 10dB attenuator is inserted
into the receiving antenna circuit, reducing interfering
signals and giving more stable reception. In normal
operation the ATT switch is left in the OFF (up) position.
5-2-5 P.B. (PASS BAND) TUNING
Pass Band Tuning is a system in the receive mode to narrow
the band width (selectivity) of the frequencies that will pass
through the crystal filter electrically from either the upper
or flower side continuously by up to 1.5KHz. This is very
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effective in reducing interference from nearby signals.
For example, while receiving in the LSB mode, if you get
interference from a lower frequency (interfering signals are
high pitched tones), narrow the band width by turning the
P. B. tuning contro! counter-clockwise. When the interfer-
ing signals are low pitched tones, they are from a higher
frequency, and you should narrow the band width by
turning the P. B. tuning control clockwise.
When receiving in the USB mode, the band width is nar-
rowed in the opposite manner. Interference from a higher
frequency will be high pitched tones, and the P. B. tuning
control should be turned clockwise. Interference from a
lower frequency will be low pitched tones and the P. B.
tuning control is turned counter clockwise.
When P.8. TUNE knob is turned
counter-clockwise.
Receiving LSB signal
BFO frequency Pass band is narrowed
Receiving signal and interfering signal
goes out of the pass band.
interference
interfering signal
When P.B. TUNE knob is turned
clockwise.
Receiving LSB signal
ia interfering signal Pass band is narrowed
and interfering signal
BFO frequency ; ig signal
Interference
goes out of the pass band.
Receiving signal
This control can also be used for audio tone adjustment, so
it may be set for the most comfortable reception. The Pass
Band Tune functions only in SSB and RTTY, not in the
CW mode.
5-2-6 TRANSMITTING
Before transmitting, listen in the receive mode to make sure
your transmission will not interfer with other communi-
cations. If possible, use a dummy load for adjustment
instead of an antenna. Set knobs and switches as follows.
MIC GAIN CENTER
COMP CONTROL OFF (counter-clockwise til it
“clicks’’)
METER SELECT SWITCH ALC
Other knobs and switches are Jeft in the same positions as
for receiving. When the T/R switch is moved to transmit,
or when the PTT (push to talk) switch on the microphone
is depressed, the transmit LED is illuminated. By speaking
into the microphone, the meter needle will move according
to the strength of your voice and SSB signals will be
transmitted. Set the MIC Gain control so that the meter
needie stays well within the blue ALC zone at voice peaks.
Now set the Meter Select switch to the Ic position. The
meter needle should be at about 300mA with no signals
into the microphone. Change to the receive mode by
moving the T/R switch to receive, or release the mi-
crophone PTT switch.
5-2-7 HOW TO USE THE SPEECH PROCESSOR
The IC-701 has a low distortion RF Speech Processor
built into the set. In equipment having tubes for the final
stage, using an RF Speech Processor causes concern about
possible tube damage caused by the increase in talk power.
However, since the |C-701 is completely solid state, includ-
ing the finals, and designed for heavy duty use, this worry
is eliminated. The RF Speech Processor also enables
greater talk power and better results in DX operation.
Follow the steps below for use of the RF Speech Processor:
MIC GAIN CONTROL
TURN FULLY CLOCKWISE
METER SELECT SWITCH
ALC POSITION
COMP CONTROL
TURN FROM THE OFF POSITION UNTIL IT
“CLICKS” ON
Switch to transmit and turn the COMP contro! slowly
clockwise while speaking into the microphone until the
meter needle moves within the ALC blue zone. (usually
_ about 2/3 clockwise)
Set the meter select switch to the COMP position. Speak
into the microphone while transmitting. Turn the MIC gain
control down (CCW) so that at the voice peaks, the meter
needle is close to ‘0’’ on the COMP scale.
Further reduction of the MIC GAIN control to a point
where the meter just moves in both COMP and ALC
positions yields the best voice quality and maximum peak
(not average) power output.
The mic gain and compression levels vary on different
bands, so it will sometimes be necessary to repeat the above
procedures carefully for the best result.
The COMP control should be turned OFF or MIC carefully
set for minimum comp as below for all communications
other than DX operation for a very natural voice quality.
5-2-8 HOW TO USE THE VOX CIRCUIT
The IC-701 has a built-in VOX (voice operated relay) which
allows automatic T/R switching by voice signals into the
microphone. For VOX use, set the knobs inside the top
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access cover as follows:
VOX GAIN CONTROL
FULLY COUNTER-CLOCKWISE
ANTI VOX CONTROL
FULLY COUNTER-CLOCKWISE
VOX DELAY CONTROL
FULLY CLOCKWISE
Turn the VOX switch on the front pane! to the ON (down)
position. Leaving the T/R switch in the receive position
and without pushing the PTT switch, turn the VOX gain
control clockwise while speaking into the microphone. At
a certain point, the T/R switching circuit will be activated
by your voice. This is the proper position for the VOX
Gain control. Set the VOX Gain control at a level which
provides for T/R switching at your normal voice level.
Transmit-release time (the time delay before the set auto-
matically returns to receive when you stop talking) is
controlled by the VOX delay control. Turning the control
counter-clockwise makes the time shorter. Set it at a
position which is comfortable and which allows for short
pauses in normal speech.
Adjust the ANT! VOX control so that the VOX circuit is
not activated by sounds from the speaker by turning the
control clockwise while receiving a signal.
5-3 CW OPERATION
5-3-1 RECEIVING
For CW reception, set the MODE Select Switch to the CW
or CW-N position. Other switches and knobs are set the
same as for SSB reception. The Pass Band Tune circuit is
preset internally for CW reception, therefore, when the
MODE Select Switch is set at the CW or CW-N (CW
NARROW) position, the Pass Band tuning control on the
front panel is inactivated.
In addition to a crystal band pass filter, an audio active
filter is built-into this unit. When the MODE Select Switch
is set at the CW-N position, this audio filter is activated and
the total selectivity of CW reception is improved. Also,
with this filter, internal noise is reduced for comfortable
CW reception and an improved signal to noise (S/N) ratio.
5-3-2 TRANSMITTING
Insert the keyer plug into the KEY Jack on the rear panel
of the unit, and set knobs and switches as follows:
COMP CONTROL OFF (Fully counter-clockwise)
METER SELECT SWITCH Po POSITION
Other knobs and switches are set the same as for CW
reception.
By setting the T/R switch to Transmit, the transmit LED
is lit and shows that you are ready for CW transmission.
When you key the keyer, the meter needle moves and your
CW signal is transmitted. To decrease the transmitting
power, turn the COMP Control clockwise to ON and rotate
to adjust while watching the meter needle on the Po scale
for the desired output power.
5-3-3 CW MONITOR
When keying, the side tone oscillator circuit is activated
and a 900Hz tone is heard from the speaker. The loudness
of this tone is adjusted by rotative the CW MONI Control,
located under the access cover. Rotating the CW MONI
Control clockwise makes the tone louder. (In the receive
mode, this side tone is audible and can therefore be used
for Morse Code Practice, adjustment of the keyer, etc.)
To receive again, place the T/R switch in the receive
position.
5-3-4 SEMI BREAK-IN OPERATION
The IC-701 has Semi Break-In CW capability when using
the VOX function. When keying, the unit is automatically
set in the transmit mode. After keying, it is returned to the
receive mode, also automatically, after a given transmit-
release delay time constant. Leave the T/R switch in the
Receive position, and set the VOX switch in the ON (down)
position.
The transmit release delay time constant is set by adjusting
the CW DELAY Control located under the access cover.
Turning the CW DELAY Control clockwise will make the
transmit release time longer. Set for your keying speed.
5-4 RTTY OPERATION
For RTTY operation, a teletypewriter and a demodulator
(terminal unit) which is operational with audio input are
necessary. Any demodulator with 2125/2295Hz (narrow,
170Hz shift) or 2125/2975Hz (wide, 850Hz shift) filters
can be used with the IC-701. You can select NARROW or
WIDE shifts by setting the RTTY SHIFT Switch, located
under the Access Cover, to N or W. Fine adjustment of the
MARK frequency can be accomplished by rotating the
NARROW or WIDE variable resistors, located behind the
RTTY SHIFT Switch.
5-4-1 RECEIVING
Audio signals for the demodulator can be supplied from
Pin 4 of the ACC socket on the rear panel, or from the
PHONES jack on the front panel. The level of the audio
signals from Pin 4 of the ACC socket does not vary by
turning the AF GAIN Control.
Set the MODE Select Switch to RTTY. The frequencies
for NARROW shift are 2295Hz for MARK and 2125Hz for
SPACE. For WIDE SHIFT, they are 2975Hz for MARK
and 2125Hz for SPACE.
If you have an AFSK generator, set the MODE Select
Switch on LSB for RTTY operation. Then the frequencies
for NARROW SHIFT are 2295Hz for SPACE and 2125Hz
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for MARK. For WIDE SHIFT, they are 2975Hz for
SPACE and 2125Hz for MARK. Also turn the P. B. Tune
control fully clockwise for clear reception.
5-4-2 TRANSMITTING
For Keying of the FSK (Frequency Shift Keying) circuit,
insert a high speed relay’s coil into the loop current circuit
of the teletypewriter and connect the relay contacts to Pins
8 and 9 of the ACC socket on the rear panel. The relay
contacts make during the SPACE and break during the
MARK.
When a high speed relay is used
ACC SOCKET
When a level converter for TTL level signals is used, connect
the output of the converter to Pins 8 (ground) and 9 of the
ACC socket. Apply HIGH level (5V) signals for the MARK
and LOW (OV) signals for the SPACE. When using an
AFSK generator that has 2125Hz for MARK and 2295Hz
(2975Hz in wide shift) for SPACE, connect the output
signals for the AFSK generator to the MIC connector on
the front pane! and turn the MODE Select switch to the
LSB mode. In this case, you can use the VOX operation
available in the SSB mode, so receive to transmit change
over is very easy.
TTY
MACHINE
SELECTOR
MAGNETS
KEYBOARD
LOOP CURRENT
POWER SUPPLY
When a level converter is used
ACC SOCKET RITY
TTY
DEMODULATOR
MACHINE
(TU)
SELECTOR
MAGNETS
LOOP
CURRENT
KEYBOARD
POWER SUPPLY
4 BREAK
yr SWITCH
LEVEL CONVERTER
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When an AFSK generator is used
PHONES AF
JACK
RTTY
DEMODULATOR
(TU)
uM 7
60mA or 20mA LOOP meen
LOOP CURRENT
POWER SUPPLY
MIC
CONNECTOR
5-5 OTHER OPERATIONS
5-5-1 VSWR READING .
The IC-701 has a built-in VSWR meter for checking antenna
matching in order to avoid problems caused by VSWR.
Set the METER Select switch to the Po position, the T/R
switch to Transmit, and Mode switch to the RTTY position.
Adjust the SWR SET control so that the meter needle
points to ““SET’’ on the meter scale. Set the SWR switch,
located under the access cover, to the SWR _ position.
(Before your unit is shipped, the SWR switch is fixed in
place in the SET position with a plastic screw. Remove
this screw before trying to make VSWR readings). With
the switch in the SWR position, SWR reading can be seen
on the meter. Although this unit is built to handle VSWR
of up to 2:1, it is recommended that the antenna(s) be
adjusted for the lowest possible VSWR. After taking the
reading, return the switch to the SET position. ALSO BE
SURE THAT THE ANTENNA IMPEDANCE IS 52 OHMS
OR THERE MAY NOT BE ANY OUTPUT. OTHERWISE
THERE WILL BE DAMAGE TO THE TRANSCEIVER.
The final transistors used in the 1C-701 are of good design
and are protected to a resonable extent by circuits
incorporated in the set. These devices can be expected to
have an indefinite lifetime since there are no cathodes to
burn out. Under some conditions, however, they can be
abused beyond tolerance and may have to be replaced.
When in doubt about antenna systems, use the lowest
power setting possible to achieve meaningful readings. Use
a good tuner or transmatch when necessary. Always use
caution and exercise judgement when testing RF power
generators.
5-5-2 AUTO DIMMER
For optimum visual comfort, the meter lamp and frequency
AFSK
GENERATOR
display LEDs are automatically dimmed and brightened
depending on the brightness or darkness of the surrounding
light by use of a built-in Dimmer Photosensor, located on
the right side of the frequency display on the front panel.
For the AUTO DIMMER to function properly, take care
that the dimmer photosensor is not covered by your hand
or other object.
The threshold for the functioning of the AUTO DIMMER
can be adjusted by turning the DIM GAIN Control, located
under the access cover. Rotating the control counter-
clockwise will lower the operation threshold of the circuit.
The circuit can be turned OFF by the DIM switch located
also under the access cover.
5-5-3 WWV RECEPTION
To receive WWV (or other standard frequency station), set
the BAND SELECT switch to the 14MHz band and the
MODE switch to the USB or LSB position. Tune to
15.000.0MHz on the frequency display. The WWYV signal
can be used for alignment of a frequency counter, marker
oscillator, or the frequency display.
5-5-4 SIMPLE FREQUENCY ALIGNMENT
A very accurate frequency counter is necessary to align the
frequency of the IC-701. However, the frequency can be
aligned simply by receiving the WWV signal.
1. Set the frequency display to 15.000.0MHz and be sure
that you are receiving the WWV signal.
2. Set the Mode Select switch to CW. A 900Hz beat can
be heard.
3. Short the KEY Jack on the rear panel so that the CW
sidetone also becomes audible.
4. Rotate the FREQUENCY SET Control, located under
the access cover, so that the two tones are of the same
pitch. If the tones are difficult to adjust because of a
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difference in their strengths, adjust the CW sidetone level
with the CW MONI control, also located under the
access cover, until the strengths are the same.
WHEN ALIGNING THE FREQUENCY, DO NOT PUT
THE UNIT IN THE TRANSMIT MODE.
Be sure the T/R switch is in the Receive position, the VOX
switch is OFF, and that you do not touch the PTT switch
on the microphone.
5-5-5 SATELLITE COMMUNICTION
At present there are two active satellites for amatuer radio
use, though more are being planned. AMSAT OSCAR 7
5-5-6 RECEIVE ANTENNA TERMINALS
The RECEIVE ANT IN jack is connected to the input
terminal of the receiving section, and the RECEIVE ANT
OUT jack is connected to the antenna connector through
the internal T/R antenna switching circuit. These two jacks
are normally jumpered with a cable, but can be used with:
1. A receiving pre-amplifier
2. A separate receiver
3. Separate receiver and transmitter antennas.
If you wish to use a receiver pre-amplifier, connect it
between the receiver input and antenna output terminals.
CONNECTION OF A PRE-AMPLIFIER
ANTENNA
OTHER AO-8
STATION
was launched in November, 1974, and AMSAT OSCAR 8
was launched in March, 1978. Satellite communications
can be made by using an [C-211/211E for transmitting and
an !C-701 for receiving. For operation of the IC-211/211E
and the IC-701 and for frequency information, refer to the
chart below.
Since communication satellites are moving at very high
speeds, the down-link signals can be heard on a higher
frequency than the real frequency as a satellite approaches,
and on a lower frequency as it travels further away.
Further information on communicating through satellites
can be found in various amateur radio books and
periodicals.
AO-7 - AO-8 FREQUENCY CHART
MODE A
UP LINK
FREQUENCY
145.85MHz
DOWN LINK
FREQUENCY
29.4MHz
145.95MHz 29.5MHz
BEACON FREQUENCY
AO-7 29.502MHz
29.402MHz
lf a separate receiver is used, connect it to the receiver
antenna output terminal. For a separate receive antenna,
connect it to the receiver input terminal.
RECEIVE ANT
RECEIVER ce) ANT
IN OUT
TRANSMITTER
PRE-AMPLIFIER
® INPUT TERMINAL
® OUTPUT TERMINAL
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