Yaesu FT-480R User manual

INSTRUCTION
/
MANUAL
FT-4S0R
For Service Manuals Contact
MAURITRON TECHNICAL SERVICES
8 Cherry Tree Rd, Chinnor
Oxon OX9 4QY
Tel:- 01844-351694 Fax:- 01844-352554
Email:- [email protected]
YAESU MUSEN CO., LTD.
TOKYO JAPAN

TABLE OF CONTENTS
(Page)
GENERAL
DESCRIPTION”
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PANEL
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SWITCHES
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PANEL
CONNECTIONS
AND
SWITCHES
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FT—480R
MICROPROCESSOR CONTROLLED
2 METER ALL—MODE TRANSCEIVER
GENERAL DESCRIPTION
The
FT-480R
is
a
revolutionary.
high
performance
USB.
LSB.
FM,
and
CW
transceiver
for
the
most
demanding
2-meter
operator.
Controlled
by
a
NMOS
4-bit
microprocessor,
the
FT-480R
features
full
PLL
synthesis
in
10
Hz.
100
Hz,
|
kHz.
20
kHz
(US
model),
and
100
kHz
steps.
The
extremely
compact
size
of
the
FT-480R
makes
this
model
particularly
well
suited
for mobile use.
The microprocessor chip allows never-before-possible operating flexibility. As many as
four memory channels may be programmed to your favorite frequencies, and by switching
to the MEMORY SCAN position, all four memory channels will be scanned.
Digital display of the operating frequency is provided. The front panel meter consists of a
string of bright LED’s, for easy monitoring of the received signal strength and transmitter
output.
The standard microphone features a PIT switch and up/down scanning controls plus a
tone call button for repeater operation.
Among the convenience features of your FT-480R are receiver offset tuning for CW and
SSB, and a digitally synthesized dual VFO system.
We recommend that you read this manual in its entirety, so as to derive maximum benefit
from your new FT-480R, an exciting breakthrough from the communications experts
... Yaesu,
For Service Manuals Contact
MAURITRON TECHNICAL SERVICES
8 Cherry Tree Rd, Chinnor
Oxon OX9 4QY
Tek:- 01844-351694 Fax:- 01844-352554
Email: [email protected]

SPECIFICATIONS
GENERAL
Frequency coverage:
*143.500—148.500 MHz
Modes of operation:
SSB (USB, LSB), CW, and FM
Synthesizer steps:
SSB, CW
*FM
10 Hz, 100 Hz, | kHz
1 kHz, 20 kHz, 100 kHz
Power requirements:
13.8 volts DC, negative ground
Current consumption:
DC 0.5 amps receive
DC 3.0 amps transmit
Antenna impedance:
50 ohms
Case size:
60 (H) x 180 (W) x 240 (D) mm
Weight:
Approx. 2.9kg
TRANSMITTER
Power input:
SSB 30 watts PEP
FM/CW 30 watts DC
Carrier suppression:
Better than 40 dB
Unwanted sideband suppression:
Better than 40 dB
Spurious emission (SSB):
At least 60 dB down
Frequency response:
300—2700 Hz (—6 dB)
FM Deviation:
+5 kHz
Microphone impedance:
600 ohms
RECEIVER
Sensitivity:
SSB, CW 0.5 nV for 20 dB S/N
FM 0.35 uV-for 20 dB QS
Selectivity:
SSB, CW 2.4 kHz at 6 dB down
4.1 kHz at 60 dB down
FM 14 kHz at 6 dB down
25 kHz at 60 dB down
Image response:
Better than —60 dB
Audio output impedance:
8 ohms nominal
Audio output:
2.0 watts @ 10% THD
*
USA
Model
(Model
A)
|
Frequency Synthesizer Steps (Hz)
Model Range SSB, CW FM
(MHz)
ious erecta S
143.5—
A 148.5 10 | 100 \K
144.0—
B 146.0 10 100 1K IK
143.5-
c 148.5 Uae i a
| 1K 1K 12.5K 1750
| {IK {kK 12.5K
eee
FT-480R Model Chart
—-9Q-

ICs:
MC1496G
MCI4011B
MC14560B
MC14028B
MC14069B
MC14002B
uAT8LOS
puPC7808H
uPC577H
uPC1037H
uPC2002V
uPC7805H
uPD4094B
uPD1511-11
TC9122P
TC5081P
TCS5082P
SN16913P
SN76514N
HD10551
MB87i8A
TA7612AP
FETs:
2SKI9TMY
I DARwWH
SEMICONDUCTORS
2SKI9TMGR 3
2SK30AY
2SK51
3SKS59Y ]
3SK70
3SK73Y 8
Transistors:
2SATISC
2SA733P/Q
2SC535A
2SC535B
2SC732TMBL
2SC945P
2SC945Q
2SC945K
2SC1383R
2SC1583
28C1674L
2SC1815Y
2SC181SGR
2S8C1945
28C2002L
2802053
2SC2166
2SC2785E
ww i)
see Wn OH
— eet re OD ON tO
—
MPSAI3
Diodes:
1S188FM
1$1007
181555
182209
U05B
1SS53
10D]
MV104
HZ11B-1
LEDs:
TLG-205
TLR-205
TLR-226
TLY-226
TLG-226
FCD:
LD8231/F1P9C5
tJ
Ne} —
rhe | Pe BR oO
_—
Mm ty WY to to
Specifications
subject
to
change
without
notice
or
obligation.
For Service Manuals Contact
MAURITRON TECHNICAL SERVICES
8 Cherry Tree Rd, Chinnor
Oxon OX9 4QY
Tel:- 01844-351894 Fax:- 01844-35254
Email:- [email protected]
ACCESSORIES
Microphone
Power Cord
Spare Fuses (5A)
Stand
Miniature Phone Plug
Mobile
Mounting
Bracket(RO062900)
1
ea.
TONE IN Connector
(M3090028) 1 ea.
(T9002805) | ea.
(Q0000005) 2 ea.
(ROO62300A) 1 ea.
(P0090034) 2ea.,
(P0090174) Lea.

FRONT PANEL CONTROLS AND SWITCHES
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The FT-480R has been designed for ease of opera-
tion. However, the operator may not be familiar
with some controls since the FT-480R utilizes
modern computer technology. Be sure you thor-
oughly understand the function of each control
and indicator before operating this equipment.
(1) SQL
The squelch control quiets the receiver in the
absence of a signal on FM. It should be set to the
point where the background noise just disappears,
in order to provide maximum sensitivity.
(2) VOL
This control is the main ON/OFF switch for the
transceiver, and it also sets the audio output level
to the speaker. Clockwise rotation increases the
audio output level.
(3) STEP
The 3 positions of this switch control the tuning
rate of the Main dial, as shown in Table 1.
MAIN DIAL FREQUENCY
STEP SWITCH COVERAGE PER STEP
POSITION —_—-.-
SSBICW | OFM
= Se
S 1OHz =} 1 kHz
M 100 Hz #90 kHz
F | kHz. *100 kHz
Table 1
* USA Model (Model A)
y)
ee a
6)
® @
(4) MEMORY
This switch selects the MS mode (Memory Scan)
or one of the four frequencies that the operator
has programmed into memory. Memory scan
control is exercised via the UP/DOWN switches on
the microphone.
(5) MAIN TUNING KNOB
The tuning knob is used to control the receive and
transmit frequencies over the entire 2 meter
amateur band. It is activated when the DIL button
is pushed.
When the transceiver is initially turned on, the
display will indicate [47.000.0 MHz, and the dial
may be turned from that point to the desired
operating frequency.
(6) MODE
This switch selects the mode of operation: USB
(upper sideband), LSB (lower sideband), CW (code
operation), and FM (frequency modulation).
This switch also selects the FM _ transmitting
frequency.
:The transmitting frequency is 600 KHz
lower than the receive frequency.
SIMP : Simplex operation.
+ : The transmitting frequency is 600 KHz
higher than the receive frequency.
(7) MIC
The
MIC
jack
is
used
for
microphone
input,
PTT
control,
and
scanner
control
lines.

(8) S/PO
A string of LEDs provides indication of signal
strength and relative power output.
(9) ON AIR
This indicator lights up during transmission.
(10) BUSY/MOD
This indicator has a dual function: it will light up
when the channel is occupied, or indicate modula-
tion during FM transmissions.
(11) CLAR Indicator
This lamp lights when the clarifier switch is
pushed.
(12) LOW
This lamp lights when the HI/LOW switch is in the
LOW position.
(13) Digital Display
The digital display indicates the operating fre-
quency. In the priority mode, the character “‘P”
will be illuminated at the far right-hand side of the
window. Also, the memory channel in use will be
indicated for easy frequency reference.
(14) T.CALL
When this switch is pushed, the PTT line will close,
and a 1750 Hz or 1800 Hz tone will be transmitted
for accessing repeaters.
(15) CLAR
The clarifier switch allows +10 kHz offset of the
receive frequency from the dial or memory fre-
quency. Clarifier tuning is accomplished via the
main tuning dial. When the CLAR switch is
pushed, the scanning step selector should be set to
10 Hz or 100 Hz; if not, control will be returned
to the main dial, with the clarifier being disabled.
(16) M (Memory)
This switch is used for programming a frequency
into memory.
(17) VFO A/B TXA
This switch, when pressed, allows split operation
using the two internal VFOs.
(18) PRI
While operating in the dial tuning mode, the
PRIORITY switch allows scanning of the main
dial and one of the memorized frequencies every 5
seconds. The SCAN switch controls the stopping
of the scanner on a busy or clear channel.
(19) F.SET
This
switch,
when
pressed,
clears
all
digits
of
the
operating
frequency
below
the
step
frequency
you
are
using.
(20) HI/LOW
This switch, when pressed, reduces the transmitter
power from 10 watts to 1 watt RF output.
(21) MR (Memory Recail)
This button transfers frequency control from the
main dial to the memory channels.
(22) NB (Noise Blanker)
This switch, when pressed, activates the noise
blanker for minimizing pulse-type noise.
(23) DIL (Dial)
This switch, when pressed, transfers frequency
control from the memory channels to the main
tuning dial.
YM-40 MICROPHONE CONNECTIONS

REAR
PANEL
CONNECTIONS
AND
SWITCH
For Service Manuals Contact
MAURITRON TECHNICAL SERVICES
(1)
ANT
Cherry
Tree
Rd,
Chinnor
=:
(6)
POWER
bce
z
Oxon
OX9
4QY
.
This
is
the
main
antenna
connectetro1844-351694
Fax:-
01844-252554
This
receptacle
accommodates
the
power
cord.
A
Email:
enquines@maurironcouk
fice
rated
at
5
amps
is
located
in
the
power
cord.
(2)
TONE
IN
CONNECTOR
This
connector
is
provided
for
the
optional
exter-
|
nal
FTS-64E
Tone
Encoder,
which
synthesizes.
[
WARNING
32
CTCSS
or
tone
burst
frequencies.
WHEN
REPLACING
FUSES,
BE
CERTAIN
TO
USE
A
FUSE
OF
5
AMP
RATING.
(3)
KEY
OUR
WARRANTY
DOES
NOT
COVER
This
is
the
key
jack
for
CW
operation.
The
key-up
th
Sa
a
Be
PS
Or
ae
voltage
is
3.5
V,
while
the
key-down
current
is
L
;
|
approximately | mA.
(4)
EXT
SP
ofr
Ig
This
is
a
miniature
phone
jack
for
connection
to
an
external
speaker.
Insertion
of
a
plug
into
this
jack
automatically
cuts
off
the
internal
speaker.
(5) BACKUP
When
this
switch
is
placed
in
the
ON
position,
and
DC
power
is
still
connected
to
the
POWER
con-
nector,
the
memory
circuit
will
still
be
held
in
EXTERNAL
SPEAKER
CONNECTIONS
operating
condition.
If
DC
power
is
removed,
though,
the
memorized
frequency
will
be
lost.
TX TONE INPUT (approx.0.35 V)
+13V BURST INPUT (approx. 0.2 V)
TONE
IN
CONNECTOR
KEY
CONNECTIONS

UNDERSIDE CABINET SWITCHES
(1) SAT (Satellite)
This switch allows the operating frequency to be
changed while transmitting. This feature is useful
especially for satellite operation, for it allows the
operator to zero on the proper frequency within
the satellite passband. Neither VFO A/B TXA nor
the CLARIFIER function works when the SAT
switch is placed in the ON position.
(2) SCAN
This switch will select scanning stop on a busy or
clear channel in the FM mode. Manual scanning
“ “ies : stop is also provided on all modes.
HAI - o (3) BURST
ai
o
The BURST switch applies a short “‘tone burst” to
oa
ae
the
carrier
at
the
start
of
each
transmission
in
the
Oo:
:
“ON”
position.
This
is
normally
used
only
for
“tone
access”’
repeater
actuation.
CAUTION
THE WIRE STAND SHOULD BE INSERTED
IN THE MOUNTING HOLES ON’ THE
BOTTOM COVER IN ORDER TO PREVENT
DAMAGE TO THE SWITCHES ON THE
COVER.
|
BLACK
SS =,
FUSE HOLDER
POWER CORD CONNECTIONS

INSTALLATION
ANTENNA CONSIDERATIONS
The FT-480R is designed for operation using an
antenna presenting a 50 ohm resistive load. The
automatic final transistor protection circuitry will
reduce the power output to protect the transistors
when a high antenna SWR is encountered. The
SWR on the antenna should, if possible, be kept
below 1.5 : 1 at all times to secure full output
from the transceiver.
In most cases, coverage is a function of antenna
height. The antenna for base station operation
should be located as high and in the clear as
possible. Vertical polarization is standard for FM
communications in most areas, so be sure that your
antenna is oriented appropriately. Popular anten-
nas for base station use include the 5/8 wavelength
vertical or one of the many stacked dipole arrays.
For accessing repeaters a long distance away, a
Yagi or other high gain directional array may be
required.
For mobile applications, the most popular anten-
nas are the 1/4 wavelength vertical and the 5/8
wavelength vertical, which shows approximately
3 dB gain over the 1/4 wavelength vertical.
Do not economize on coaxial cable, as much
power can be wasted in lossy transmission line.
For mobile use, the RG-58A/U type of coax may
be used. To minimize loss, use the shortest length
that is possible. For base stations, use type RG&A/
U coaxial cable. For very long runs, type
RGI7A/U, aluminum-jacketed ‘‘foamflex” coax,
or air dielectric “‘heliax”’ cable may be used.
The optional antenna duplexer AD-1! allows the
MOBILE INSTALLATION
For mobile service, the FT-480R should be in-
stalled where the digital display, controls, and
microphone are easily accessible for operation.
The transceiver may be installed in any position
without loss of performance. A suitable location
would be atop the transmission tunnel. A universal
bracket is supplied with your transceiver for
mobile installation. Refer to Fig. | for mounting
details.
1. Use the universal mounting bracket as a
template for positioning the mounting holes.
Use a 3/16” diameter bit for drilling these
holes, allowing clearance for the transceiver,
its cables and microphone, and its controls.
Secure the mounting bracket with the screws,
washers, and nuts supplied, as shown in the
drawing.
Ease the transceiver into the guide rail, and
slide it into the desired position. Tighten the
knobs on the outside of the universal bracket
to secure the transceiver.
The microphone hanger may be installed
wherever convenient for access to the micro-
phone.
Power connections should be made directly to the
automobile battery. Routing through the cigarette
lighter may cause the lighter fuse to blow if the
fuse is not of sufficient rating. As well, connection
directly to the battery allows the memory circuits
to remain activated when the ignition is turned off,
using the BACKUP switch.
operation on both 50 and 144 MHz using a single For Service Manuals Contact
antenna (RSL-50 or RSL145).
See your Yaesu dealer.
50/I44MHZ ANTENNA
ANT OUPLEXER
YAESU AD-I
MAURITRON TECHNICAL SERVICES
8 Cherry Tree Rd, Chinnor
Oxon OX9 4QY
Tek:- 01844-351694 Fax:- 01844-352554
Email:- [email protected]
AD-1 ANTENNA
DUPLEXER

STAND
Figure |
Connect the RED lead of the power cord to the
POSITIVE (+) battery terminal, and connect the
BLACK lead to the NEGATIVE (—) terminal. If it
is necessary to extend the power cable, use #16
AWG insulated copper wire, and use the minimum
length practicable to reduce voltage drop.
WARNING
NEVER APPLY AC POWER TO THE REAR
PANEL POWER JACK OF THE TRANS-
CEIVER. NEVER CONNECT A DC POWER
SOURCE OF GREATER THAN 15 VOLTS
TO THE REAR PANEL POWER JACK.
ALWAYS REPLACE FUSES WITH A FUSE
OF THE PROPER RATING. FAILURE TO
OBSERVE THESE SIMPLE PRECAUTIONS
WILL VOID ALL WARRANTIES ON THIS
EQUIPMENT.
CC
DASHBOARD
“. MOUNTING
€5 BRACKET
GUIDE RAIL
Connect the power cable to the POWER receptacle
on the rear apron, connect the coaxial cable from
the antenna to the rear apron ANT receptacle, and
connect the microphone to the jack appropriate
for the microphone in use. An external speaker
may be connected to the rear apron SP jack, if
desired. Use the speaker plug supplied with the
transceiver. Insertion of a plug into this jack auto-
matically cuts off the internal speaker.
BASE STATION INSTALLATION
A base station mounting stand is supplied with
your transceiver, to provide easier viewing of the
display and controls. A power supply capable of
supplying 5 amps at 13.8 VDC is required for
operation from AC mains. The FP-80A AC power
supply option provides the required 13.8 VDC for
the FT-480R transceiver. See your Yaesu dealer.
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3.3K
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NOTE
J ALL RESISTORS GRE IN v4W UNLESS
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2ALL CAPACITORS ARE yk
FP-80A
POWER
SUPPLY

OPERATION
The all solid-state design of the FT-480R means
that tuning procedures are very simple. The follow-
ing paragraphs will describe the tuning procedures
for receiver and transmitter operation.
INITIAL CHECK
Before connecting the transceiver to the power
supply, be certain that a fuse of the proper rating
is in use, and that a 50 ohm antenna has been
connected to the antenna jack.
FREQUENCY SELECTION USING MAIN DIAL
When the transceiver is initially turned on, the
digital display will read the preset frequency
147.000.0 MHz, and frequency control will be via
the main tuning dial. After memory, scanning, or
priority operation, pressing the DIL button will
return control to the main dial. Rotate the dial to
secure the operating frequency desired. Since tun-
ing steps depend on the combination of the MODE
switch and STEP switch as shown in Table 1, use
the synthesizer step for easy tuning. When the
upper or lower bandedge is reached the next
synthesizer step will automatically be to the
opposite bandedge. Thus, after 148.499.9 MHz,
the next step is 143.500.0 MHz. While transmit-
ting, the operation frequency can not be changed
in any operation modes except the satellite mode.
RECEIVER OPERATION
Preset the controls and switches as follows:
MODE .......... Desired mode
SOE sata: Fully counterclockwise
STEP. ay tite hyenas Desired synthesizer step
VFO A/B TXA...VFO*‘A” position
SCAN? sod naked. MAN position
All other switches should initially be turned off.
Rotate the VOL control clockwise to turn the
transceiver on and adjust for a comfortable level.
(1) SSB mode
Using the main tuning dial, tune in an SSB signal.
The STEP switch should be set to M or F position
so that you can secure the operating frequency
desired ir 100 Hz or | kHz steps. When you get
close to the desired frequency, set the STEP switch
to S position for 10 Hz step in order to tune in the
signal clearly. When pulse type noise such as
ignition noise is encountered, press the NB (noise
blanker) switch.
(2) CW mode
With the clarifier off, tune in a CW signal. When
the incoming signal is tuned to a beat note of
800 Hz, your transmit frequency will coincide with
that of the other station. If another beat note is
desired, or if the other station drifts, then use the
clarifier function.
(3) FM mode
Using the main tuning control, tune in an FM
signal for a maximum and steady S-meter reading
and a clear, natural voice output from the speaker.
Set the STEP switch to the M (20 kHz) position,
as almost all FM stations use 20 kHz steps. When
you change the operating mode from SSB/CW to
FM, you may clear the display and operating
frequency to the next lowest 20 kHz step by
pressing
the
F
STEP
button.
All
the
digits
of
the
operating
frequency
below
10
kHz
will
be
set
to
zero by pressing the F.SET button.
When the channel is clear, rotate the SQL control
to the point where the background noise is just
silenced. Do not rotate the SQL control much
beyond this threshold point, or else the receiver
will not respond to weak signals. The BUSY/MOD
lamp will light up when the squelch circuit is
opened. If the S-meter wobbles, or if it is impos-
sible to obtain clear audio, it is possible that the
incoming signal is on another mode such as SSB.
TRANSMITTER
Before transmission, be certain that the frequency
on which you are going to operate is clear to
prevent interruption of the other station’s opera-
tion. It is important that an antenna or dummy
load be connected to the antenna jack at all times.
(1) SSB mode
Set the MODE switch to SSB and close the micro-
phone PTT switeh, the ON ATR lamp should light

up. Speak into microphone in anormal voice; the
S.PO LEDs will light up according to the relative
output power.
(2) CW mode
Plug a key into the KEY jack on the rear panel.
In the key-down condition, the 8—9 LEDs of the
indicator will light up. Since the semi-break-in
circuit is furnished, when the key is closed, your
keying activates the transmitter, and the 800 Hz
side tone will be heard from the speaker. With the
HI/LOW switch pressed, the power output of 10
watts may be reduced to | watt, and the LOW
lamp will light up.
(3) FM mode
Set the MODE switch to FM, and close the micro-
phone PTT switch. When transmitting, 8-9 LEDs
which show relative output power will light up,
and the BUSY/ MOD lamp will be illuminated
according to the voice input. On this mode, 10
watts of RF output power can also be reduced
to 1 watt by pressing the HI/LOW button.
MEMORY OPERATION
A total of four memory channels are available for
operation. Storage and recall of memory channels
allows considerable operating flexibility. The
storage and recall procedure is extremely simple.
(1) Rotate the main tuning dial to the desired
frequency, for example 144.640.0 MHz. Now
rotate the MEMORY switch to position 1.
Press the M button to store 144.640.0 MHz
into memory channel position |.
(2) Now rotate the main tuning dial to another
frequency (for example 144.360.0 MHz). For
instant return to 144.640.0 MHz, press MR
button, the 144.640.0 | will be displayed on
the digital readout.
(3) To return again to 144.360.0 MHz, press
DIL, and you will be operating on 144.360.0
MHz.
(4) Memory channels 2, 3 and 4 may be program-
med and recalled as above.
(S) When you push the MR button, the far right
LED on the readout will illuminate, indicating
the memory channel.
(6) To return frequency control to the main tun-
ing dial, push the DIL button.
(7) Set the STEP switch to the desired step
before activating the clarifier in the memory
operation. Changing the synthesizer step with
the, CLAR switch ON will lock the operating
frequency.
SCANNER OPERATION
Fingertip switches, located on the microphone.
allow convenient frequency control, while driving.
The simple operating procedure is described below.
(1)
Set
the
bottom
panel
SCAN
switch
to
the
MAN
position.
Push
the
DIL
switch
to
select
operation
on
the
dial
frequency.
(2) Press the microphone UP switch for an instant
to shift the frequency up by one step. If you
hold the UP button for more than 1/2 second,
the scanner will be activated. To stop the
scan, press the PTT switch or one of the
scanning controls on the microphone. If you
push the PTT switch, no transmission will
occur; release the PIT switch, then press it
again for normal transmission.
(3) To scan lower in frequency, use the same
procedure, but press the DWN button.
(4) In the FM mode, to halt the scan automatical-
ly on a busy channel, set the bottom panel
SCAN switch to BUSY. In this mode, when
the scanner encounters a signal strong enough
to open the receiver squelch, scanning will
stop. When the bottom panel switch is placed
in the CLEAR position, the scan will stop
when a clear channel (one where the squelch
will not open) is found.
(5) To scan only the memory channels, rotate the
MEMORY switch to the MS (memory scan)
position. Now press the UP or DWN switch on
the microphone. The scanning rate for
memory scan will be approximately two
channels per second. The scan may be halted
in any of the ways discussed previously. The
BUSY and CLEAR positions of the SCAN
switch are particularly helpful when scanning
the memory channels in the FM mode.

PRIORITY CHANNEL OPERATION
A priority channel may be used in conjunction
with a memory channel for increased flexibility.
Here is how to set up the FT-480R for priority
operation.
(1) First program one or more memory channels
for priority use. For example, store 144.640.0
MHz into memory channel |. Set the bottom
panel SCAN switch to MAN. Rotate the main
dial to the desired frequency (for example
144.360.0 MHz).
(2) Now set the MEMORY switch to | and push
MR to recall 144.640.0 MHz and then push
the PRI (priority) switch. The display will
indicate 144.360.0 P, and every 5 seconds
the display will switch to 144.640.0 MHz
allowing you to check it for activity.
(3) If you have other frequencies stored in
memory, you may rotate the MEMORY
switch to select one for use with the priority
channel.
(4) In the FM - you may use the SCAN
switch + vd advantage during priority
operatiuu, as described in SCANNER OPERA-
TION.
(5S) If you wish to return to normal operation
from the priority mode, push the DIL button.
Now control! is shifted back to the main dial.
REPEATER OPERATION
(1) Repeater shifts of +600 kHz, and —600 kHz
are built into the FT-480R. To select these
shifts, set the MODE switch to the + or —
position respectively.
(2) To cover unusual repeater splits, you can use
the VFO A/B TXA feature.
Example: receive frequency 144.640 MHz
with 1 MHz split. Rotate the main tuning dial
to the 145.640 MHz and press the VFO A/B
TXA button on the front panel; now the
transmit frequency, 145.640 MHz, is memo-
rized. Rotate the main tuning dial to 144.640
MHz for receiving. If you close the PTT
switch, your transmit frequency will be
shifted to 145.640 MHz.
(3) A 1750 or 1800 Hz tone generator is included
with your transceiver for accessing a repeater
requiring such a tone. With the BURST switch
ON, pushing the microphone PTT will cause
insertion of an 0.5 second tone at the
begining of each transmission. When the
T.CALL switch is pushed, a tone will be
superimposed on the signal being transmitted,
for as long as the switch is held. An optional
external tone or burst generator, FTS-64E
may be connected through the rear panel
TONE IN connector.
INITIALIZING FREQUENCY/BACKUP
FEATURE
The FT-480R includes a backup feature which
will hold all memory frequencies, as well as dial
frequency, when the front panel power switch is
turned off. So long as the DC power to the rear
apron power jack is not interrupted, these fre-
quency will be held. When the power is again
turned on, the frequency and mode (memory
priority, dial, etc.) last used will be recalled, but
scanning mode is automatically reset to dial mode.
However, if the power cord is connected to 13.8
VDC circuit that is switched off along with the
automobile ignition, all memory channels as well
as the dial frequency will be reset to the preset
frequency.
SATELLITE OPERATION
The FT480R includes provision for changing the
transmitting frequency while you are transmitting
(some other synthesized transceivers lock up dur-
ing transmission). The ability to change frequency
in this manner is important during satellite opera-
tion, as Doppler shift may cause your downlink
frequency to be +3—4 kHz from a predicted value.
While listening on the downlink, and sending a
series of dots, satellite operators can usually find
themselves quite quickly.
To allow frequency change during transmission, set
the bottom panel SAT (Satellite) switch to ON.
For most satellite work on SSB or CW, the synthe-
sizer step switch should be set to Slow or Medium.
You may now close the PTT switch and vary your
frequency as desired. Note that your receiver fre-
quency will also change if you rotate the main dial.
When the SAT switch is set to ON, the + repeater
shift and receive clarifier features are disabled.
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CIRCUIT
DESCRIPTION
The
block
diagram
and
circuit
description
to
follow
will
provide
you
with
a
better
understand-
ing
of
this
transceiver.
Please
refer
to
the
block
and
schematic
diagram
for
specific
circuit
details.
RECEIVER
The
RF
signal
from
the
antenna
jack
is
applied
to
the
MAIN
UNIT
through
a
lowpass
filter
and
the
antenna
relay,
RL2zoo,.
The
signal
is
amplified
by
Qioor
(3SKS59Y),
a
dual
gate
MOS
FET
with
excellent
rejection
of
cross
modulation
and
inter-
modulation.
The
amplified
signal
is
fed
to
the
Ist
mixer,
Qjyo2_
(3SK51-03),
where
the
RF
signal
ts
mixed
with
a
local
signal
delivered
from
the
PLL
UNIT,
resulting
in
a
10.81
MHz
first
IF
signal.
The
first
IF
signal
is
passed
through
a
monolithic
crystal
filter,
XFioo
(108M30B),
which
has
+15
kHz
bandwidth,
and
amplified
by
Qio03
(3SK73Y),
which
acts
as
a
switch
driven
by
the
NB
(noise
blanker)
circuit.
The
amplified
signal
from
Qioo3
!s
fed
to
IF
amplifiers
for
each
mode.
FM
mode
signal
is
fed
to
2nd
mixer
Qzroos
(2SC535B),
where
the
signal
is
mixed
with
an
11.265
MHz
local
signal,
resulting
in
a
455
kHz
2nd
IF
signal.
The
2nd
IF
signal
is
passed
through
a
ceramic
filter,
CFyoo.1,
which
has
a
+4.5
kHz
bandwidth,
and
then
fed
to
the
FM
mode
IF
amplifier.
The
filtered
signal
is
amplified
by
Qiooe
and
Qi007
(2SC945Q)
and
passed
through
CF
i902,
which
has
4
+7.5
kHz
bandwidth.
The
filtered
FM
signal
is
amplified
by
Qyoos
(uPC577H)
and
demodulated
by
CDioo.
and
Dioto/Diorr
(1S188FM).
The
demodulated
FM
signal
is
amplified
by
Qyo12
(2SC1815GR)
and
then
fed
to
the
AF
amplifier.
SSB
and
CW
mode
signals
from
the
Qioos
are
passed
through
a
crystal
filter,
XFyo02
,
which
has
a
very
high
shape
factor,
to
improve
adjacent
fre-
quency
selectivity.
The
filtered
SSB
_
signal
is
amplified
by
Qioia
and
Qiuors
(3SK73Y),
and
then
fed
to
the
balanced
demodulator,
Quiors
(PC1037H),
where
a
carrier
signal
is
applied
from
the
carrier
oscillator
Qio4:/Qioa2_
(28C945Q),;
the
detected
audio
output
is
then
fed
to
the
AF
amplifier.
-~|4-
The audio signals from each demodulator are
passed to the active lowpass filter, which consists
of Qjo27 and Qyorg (25C945Q) to eliminate the
unwanted noise portion of the signal. The audio
signal is then fed, through the AF gain control, to
the audio output amplifier, Qiozo (uPC2002V),
providing about 2 watts of audio output to the
speaker.
AGC
and
S-METER
CIRCUIT
A
portion
of
the
IF
signal
from
Qiois
is
fed
through
Ciog0
to
a
buffer
amplifier
Qioi7
(25C-
535B).
The
amplified
signal
is
then
applied
to
the
AGC.
detector,
Diozs/Diox
(1S188FM).
The
rectified
signal
is
amplified
by
DC
amplifier
Qiois
(2SC1815Y).
This
amplified
DC
voltage
controls
gate
2
of
MOS
FET’s
in
the
RF
and
IF
amplifier.
A
portion
of
the
AGC
signal
is
buffered
by
Qioa
(2SK30AY),
and
fed
to
the
S-METER
amplifier
Qi022
(2SA733P).
This
amplified
voltage
is
delivered
to
the
front
panel
S.PO
indicator
to
illuminate
LEDs
according
to
the
input
signal
strength.
SQUELCH
CIRCUIT
A
portion
of
the
demodulated
FM
signal
from
the
ceramic
discriminator
(CDj001,
Dioio,
Dios
)
is
fed
to
noise
amplifiers
Qioos
and
Qroto
(28C945Q)
through
VRioo2
and
the
SQ
Control
(VR,,),
and
then
rectified
by
Dyor2
and
Dyois,
a
voltage
doubl-
ing
circuit.
The
rectified
signal
is
fed
to
the
base
of
Oro
(2SC1815Y),
the
squelch
control
circuit.
When
no
carrier
is
present,
the
rectified
DC
voltage
is
applied
to
the
base
of
Qioi.,
to
turn
Qi012
(2SC1815GR)
on.
With
conduction
of
Qioi,
the
base
of
Qio1.
is
grounded,
squelching
the
audio
amplifier.
When
a
carrier
is
present,
the
rectified
DC
voltage
is
reduced,
and
the
audio
amplifier
Qioi.
then
recovers
to
normal
operation.
The
BUSY
lamp
switch,
Qio13
(2SC945Q),
is
also
activated
by
the
rectified
voltage
from
the
demodulator
to
illumi-
nate
the
BUSY
lamp
when
a
carrier
is
present.

NB (Noise Blanker) CIRCUIT
A portion of the IF signal from monolithic filter
XFioo1 is amplified by Qioa7 (2SC535B), Qioas,
Qioaa, ANd Qyosq (2SC1583). The output signal is
rectified by Dyoso and Dyogo, producing a DC
voltage. This DC voltage is amplified by Qyo52
(MPSA13) and fed to gate 2 of Qjoo3, the noise
blanker gate. A portion of the DC voltage is
amplified by Qios;, and then fed to Quroas,
Qioag (2SC1583) as a noise blanker AGC voltage.
When impulse-type noise is received, the induced
DC voltage reduces the gain of Qj993, and blocks
the signal path momentarily. The noise AGC
control voltage is not, however, induced by such
impulse-type noise, because the time constant of
Ci243/Ri273 is long. Normal signals, though, induce
the noise blanker AGC voltage, reducing the gain
of the noise amplifier, allowing normal signal flow
at Qio03 -
TRANSMITTER
The discussion of the signal flow on transmit will
be on a mode by mode basis.
For Service Manuals Contact
MAURITRON TECHNICAL SERVICES
8 Cherry Tree Rd, Chinnor
Oxon OX9 4QY
Tol:- 01844-351694 Fax:- 01844-352554
; __ Emaik- [email protected]
The audio input signal from the microphone is
amplified by Qjyo3. (2SCI8I5GR) and Qiyo39
(2SC1815Y). The audio level is adjusted to the
proper level by VRjoo7, and is applied through an
active lowpass filter, Qioa9 (28C945Q), to the ring
modulator, Dyos3 —Diose. Here the audio signal
modulates the 10.81 MHz carrier signal delivered
from the carrier oscillator Qj94, (2SC945Q) and
buffer Qio42 (2SC945Q), resulting in a 10.81 MHz
double-sideband signal. The signal is amplified by
Qioa3 (2SK19TM-GR) and fed to XFjo92, a crystal
filter, where the unwanted sideband is sliced out.
The SSB signal is then amplified by Qho1a
(3SK73Y) and fed via a lowpass filter on to mixer
Qio3xs (MC1496G) and mixed with a local signal
from the PLL Unit, resulting in a 143.5—-148.5
MHz SSB signal.
SSB
The SSB signal is passed through Tyoyo—Tioia,
which are tuned exactly to the operating frequency
by varactor diodes, thus minimizing: spurious
radiation. The signal is then amplified by Qio37
(3SK70), and Qio33 (2SC2053) to the proper level
for driving the power amplifier circuit.
—15-
FM
The output audio signal at Qjo39 is amplified by
Qios: (2ZSC1I815GR) and Qio3, (2SC945Q) and
fed to the IDC circuit, consisting of Dy93, and Dyo3,
which clips both positive and negative peaks to
control the maximum possible deviation. The
clipped signal is then passed through an active
lowpass filter, Qji933 (2SC945Q) to eliminate
harmonics above the speech range caused by
clipping. The deviation level is set by VRioos
before passing the signal on to Qio34 (28C945Q)
to be amplified to the correct level and fed in to
the FM modulation unit XMj 99, .
The remainder of the signal path is then identical
to that of the SSB signal.
CW
For CW, 10.8107 MHz carrier signal is
generated by Qioaa (2SC945Q), amplified by
Qioss (28C945Q), and fed to IF amplifier Qio.4.
the
The key line is connected to switching transistor
Qins2 (28C945Q) through inverter Qyo.,
(MC14011B), which controls the gate voltages at
Qiora (3SK73Y) and Qio37 (3SK59Y), thus turning
the RF signal on and off
The signal path is then identical to that of the CW
signal.
An RC circuit connected to the base of Qiog2
produces an ideal keying waveshape for click-free
CW operation. The key line is also connected to
side tone oscillator Qy9., (MC14011B) for monitor-
ing of the code signal during CW operation. In
order to operate on semi-break-in, the Schmitt
trigger and delay circuit at Qiogo (MC14011B)
activates the RX-TX changeover relay.
POWER AMPLIFIER CIRCUIT
The RF signal from the Main Unit is amplified by
Qsroor (28C2053) and Qroo: (M57713) in the
Power Amplifier Unit, delivering approximately 10
watts of RF output to the antenna through a
lowpass filter.

POWER CONTROL CIRCUIT
When the HI/LOW switch is set to the LOW posi-
tion, the base of Qioas is grounded through VRjo:2,
and the collector current of Qjoa, is decreased.
Because the output power of Qjo9; is controlled
by Qroo3, the drive level to Qyo92 is decreased, thus
reducing the RF output power to approximately
| watt.
TONE BURST CIRCUIT
When the PTT switch is pressed, the one-shot
multivibrator consisting of Qiogo (A2, 3) (MC-
14011B) is activated to generate a pulse of 0.5—1
second duration. The pulse switches Qio5, (2SA-
733P) to supply DC voltage to Qios, (TC5082P),
where a 1750 or 1800 Hz tone signal is generated.
Pressing the T.CALL switch also switches Qj9s3 and
generates a tone signal. The tone is fed to the FM
MIC amplifier and superimposed on the transmit
signal.
ALC (Automatic Level Control) CIRCUIT
A portion of the output power from Qs. ts
applied through Cyo29 to rectifiers Dy99, and Doo.
producing a DC voltage. The DC voltage is ampli-
fied by DC amplifier Qioig (2SC1815Y) and fed to
gate 2 of Qiois to control its gain, thus preventing
overdrive. The ALC level is adjusted by VR,o93 for
proper drive to Qzoo2 -
AFP (Automatic Final Protection) CIRCUIT
If the transmitter is activated without an antenna
being connected, or if a high VSWR is present at
the antenna jack, the reflected power is detected
through T299,; and Dsoo3. The detected AFP voltage
is applied through VR2ioo2 to Qiog3 (2SC1815SY) in
the Main Unit. As the reflected power increases,
the AFP voltages also increases and consequently
Qioses conducts. The signal is fed to Qhuos
(2SC1815Y), this decreases the voltage at gate 2
of Qiows (3SK73Y), resulting in lower output
power. When the transceiver is correctly matched
to an antenna, full power output will be obtained.
PLL CIRCUIT
The PLL circuit is comprised of three PLL oscil-
lators each consisting of a reference crystal oscil-
lator, a programmable divider, a prescaler, and a
phase comparator. The PLL produces local signals
for the receiver and transmitter stages, using a
synthesis scheme which produces 10 Hz steps.
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PLL Circuit Configuration
The local signal 132.6900 MHz — 137.6899 MHz
is generated by Q392; (2SKI9TM-GR)VCO-] in the
PLL Loop 1, amplified by buffers Q3o2. (3SK51-03)
and Q3o39 (2SC535A), and passed through BPF
circuit to eliminate spurious radiation. The signal is
then coupled to the Main Unit.
A portion of the signal from the buffer Q3,22 is
amplified by Qs3o23 (3SK51) and applied to the
mixet Q3o24 (SN76514N), where the signal is mixed
with a heterodyne signal of 129 MHz from PLL
Loop 2, and its frequency is divided by program-
mable divider Q3o., (TC9122P). The digital phase
comparator Q3927 (MB8718) compares the phase
of signal from the programmable divider with that
of 40 kHz reference frequency obtained from
crystal oscillator Q3oo7 (TC5082P) (via a 1/4
divider), producing an error-correction DC voltage.
The output DC voltage is passed through an active
lowpass filter consisting of Q3o923 (2SK19TM-Y)and
Q3025 (2SC732TM-BL), and fed to the VCO-1 to
control its oscillation frequency.
In PLL Loop 2, a 64 MHz signal generated by the
VCXO Qaoi1s (2SC1674L) is fed to buffer Q3o16
(2SC535A) and on to doubler Q3929 (2SC710)
before passing to mixer Q3o.4 (SN76514N) in
PLL 1.
A portion of the VCXO signal is taken to buffer
amplifier Q3o17 (3SK73Y) before passing to mixer
Qsoig (SNI6913P), where the signal is mixed with
a 63 MHz signal generated by VCXO Qsoo0
(2SC1674L) and Qsoi9 (2SC535A), resulting in a
600 kHz signal. The 600 kHz signal is amplified by
Q3019 (2SC945Q) and fed to phase comparator
Q3o14 (TC5081P), which compares the phase of
the signal with that of the 600 kHz signal from
PLL Loop 3, producing an error-correction DC
voltage. The DC voltage is passed through a lowpass
filter and fed to the VCXO to control its oscilla-
tion frequency.
In PLL Loop 3, a 60 MHz signal is generated by
VCO-2 Qyoo, (2SKI9TM-GR) and applied through
buffers Q3902 (3SK73Y) and Q3o1, (28C535A) to a
prescaler, Q3o)2/Q3013 (HD10551), which divides its
frequency by 1/100, thus producing a 600 kHz
signal. A portion of the output of Qyoo2 is fed to
mixer Qjoo3 (SNLI6913P), where the signal is
mixed with a 63 MHz signal which is generated by
Q3o00 (2SC1674L), and applied through a program-
divider
to
phase
comparator
Q3o06
(TC5081P) which compares the phase of the signal
with
that
of
5
kHz
signal
which
is
generated
by
Qs3o07_ (TCS082P), producing an error-correction
DC voltage. The DC voltage is passed through a
lowpass filter and fed to the VCO-2 Qyoo, to
control its oscillation frequency.
mable
The frequency control signal from the PLL Control
Unit is fed to Serial/Parallel converters Qyo3, -
Qso33 (uPC4094B) and converted into BCD
code to control the dividing ratio of the program-
mable divider and the VCO and VCXO oscillating
frequency in each PLL loop.
When any VCO is unlocked. an unlock signal from
the phase comparater is fed to the unlock control
circuit consisting of Q3o4; (MPSA13) and Qyoa,
(2SA733P), which controls buffer Q3939 (2SC535A)
to mute the output from the PLL oscillator to
prevent spurious radiation.
PLL Control Circuit
In the PLL Control Unit, a 4 bit parallel processing
CPU is used to control the operating frequency,
UP/DOWN scanning, priority channel, or memory
channel selections. The CPU has one input port,
three 1/O ports and four output ports. The CPU
processes input data by means of the main dial or
other control switches in accordance with the
program stored in an ROM for control of the PLL
frequency, indication of the operating frequency,
or memory channels on digital display. The CPU
is also furnished with a function to halt transmis-
sion when any VCO is unlocked, resulting in a
fail-safe system.
For Service Manuals Contact
MAURITRON TECHNICAL SERVICES
8 Cherry Tree Rd, Chinnor
Oxon OX9 4QY
Tel:- 01844-351694 Fax:- 01844-352554
Email:- [email protected]

MAINTENANCE
AND
ALIGNMENT
This equipment has been carefully aligned and
tested at the factory prior to shipment. If the
instrument is not abused, it should not require
other than the usual attention given to electronic
equipment.
Service or replacement of a major component may
require considerable realignment. Under no circum-
stances, though, should realignment be attempted
unless the operation of the transceiver is fully
understood, the malfunction has been carefully
analyzed, and the fault has definitely been traced
to misalignment rather than part failure. Service
work must only be performed by experienced
personnel using the proper test equipment.
Never align this transceiver without having a 50
ohm dummy load connected to the antenna jack,
unless otherwise noted. Troubleshooting using an
antenna can result in misleading indications on test
equipment.
For Service Manuals Contact
MAURITRON TECHNICAL SERVICES
8 Cherry Tree Rd, Chinnor
Oxon OX9 4QY
Tel: [phone] Fax:- 01844-352554
Email:- [email protected]
PLL OUNIT
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meet —DISPLAY UNIT
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EQUIPMENT REQUIRED
(1) RF Signal Generator: Hewlett-Packard Model
8640B or equivalent, with one volt output at
50 ohms, and frequency coverage to 150
MHz.
(2) Vacuum Tube Voltmeter (VTVM): Hewlett-
Packard Model 410B or equivalent, with an
RF probe good to 150 MHz.
(3) Dummy Load/Wattmeter: Yaesu Model YP-
150Z or equivalent.
(4) AF Signal Generator: Hewlett-Packard Model
200AB or equivalent.
(5S) IF Sweep Generator: capable of output at
10.81 MHz.
(6) RF Sweep Generator: capable of output at
143—149 MHz.
(7) Oscilloscope: Hewlett-Packard Model 1740A
or equivalent.
(8) FM Deviation Meter
(9) Precision Frequency Counter: Yaesu Model
YC-500 or equivalent, with resolution to 0.01
kHz and frequency coverage to 150 MHz.
-Yo-— MAIN UNIT
Bottom View
UNIT LOCATIONS