Kenwood TM-V7A Service Manual

TM-V7A/E
CIRCUIT
DESCRIPTION
144MHz
Sub-Band
Reception
Circuit
The
signals
input
from
the
antenna
first
go
into
the
144MHz
band
main
reception
front
end
section.
After
they
are
amplified
with
a
GaAs
field
effect
transistor
(Q11),
the
divider
circuit
divides
them
into
two
systems,
the
144MHz
main
section
and
the
144MHz
sub-section,
and
they
are
connected
to
the
430MHz
band
sub-receiver
circuit.
In
the
sub-receiver
circuit,
first
the
unwanted
component
is
eliminated
with
a
filter
circuit,
then
the
signals
are
mixed
with
the
first
local
oscillator
by
a
field
effect
transistor
(Q44)
to
convert
them
to
the
first
intermediate
frequency
of
45.05MHz.
After
these
signals
are
connected
to
the
main
430MHz
band
circuit,
the
144MHz
sub-reception
is
carried
out
using
the
main
circuit.
ANT
Main
144MHz
band
aii
/\
.
SGM
XF2
iM
Main
430MHz
band
014M
Qs0
Fig.3
144MHz
sub
band
receive
circuit
block
diagram
430MHz
Sub-Band
Reception
Circuit
430MHz
band
signals
can
be
received
with
the
144MHz
unit.
First,
the
reception
signals
entering
from
the
antenna
pass
through
the
430MHz
unit
final
section
antenna
switching
diode,
go
through
the
matching
coil,
and
are
amplified
by
Q23,
a
GaAs
field
effect
transistor.
The
amplified
reception
signals
go
through
the
divider,
have
the
Q23
unwanted
signal
eliminated
by
a
band
pass
filter,
and
go
into
the
first
mixer.
In
the
first
mixer,
the
signals
are
mixed
with
the
first
local
signal
from
the
PLL,
are
converted
to
the
first
intermediate
frequency
of
38.85MHz,
then
are
received
with
the
same
operations
as
for
the
144MHz
band.
ANT
4
Main
430MHz
band
a]
=>
=>
: XFt
Main 144MHz band
Q28
A
Fig.4
430MHz
sub
band
receive
circuit
block
diagram

Kenwood TM-V7A Specifications

General Specifications

VHF frequency range	144~148MHz
UHF frequency range	438~450MHz (U.S.A/Canada)
Antenna impedance	50Ω
Usable temperature range	-20°C to +60°C (-4°F to +140°F)
Power supply	13.8V DC ±15% (11.7~15.8V)
Grounding method	Negative-ground
Frequency stability	±3ppm (-10°C to +50°C)
Dimensions (W x H x D)	140 x 54.5 x 205.5 mm

Transmitter Specifications

High power output	50W (VHF) / 35W (UHF)
Mid power output	Approx. 10W
Low power output	Approx. 5W
Spurious emissions	-60dB or less
Maximum frequency deviation	±5kHz
Audio distortion	3% or less (at 60% modulation)
Microphone impedance	600Ω

Receiver Specifications

Circuitry	Double conversion
Intermediate frequency (1st / 2nd)	38.85MHz / 450kHz and 45.05MHz / 455kHz
Sensitivity (VHF or UHF band)	0.16μV or less (12dB SINAD)
Sensitivity (Sub VHF or UHF band)	0.25μV or less
Selectivity (-6dB)	12kHz or more
Selectivity (-60dB)	28kHz or less
Squelch sensitivity	0.1μV or less
Audio output	2W or higher (8 ohms, 5% distortion)
Audio output impedance	8Ω

Weight and Dimensions

Weight	1.2 kg (2.6 lb)
Dimensions (W x H x D)	5.51" x 2.15" x 8.09"