Kenwood TM-V7A Service Manual

TM-V7A/E
CIRCUIT DESCRIPTION
@DTMF MIC/RD switching (IC510 SW NO. 22 and 23)
These switch the input to the DTMF decoder (IC506:
LC73881M) between DTMF signals including detection
signals and DTMF signals from the mic.
@MIC RD144/430MHz band switching
(1C510 SW No. 4 and 5)
These switch the signals output to RD of the MIC.
terminal to either RDU or RDS.
@DTMF RD 144/430MHz band switching
(IC407 SW No. 16 and 17)
LC73881M) to either RDU or RDS. After going through this
circuit, the signals go through DTMF MIC/RD and are input
to the DTMF decoder (1C506: LC73881M). When a busy
detection signal (PSCU or PSCS) enters the microproces-
sor (IC508), the band for which the signal was detected is
switched to when DTSS PAG ON. If a busy signal is de-
tected for both bands at the same time, the band detected
last is switched to.
@CTCSS RD 144/430MHz band switching
(1C510 SW No. 0 and 1)
These switch the input to the CTCSS decoding IC
(IC507:AK2343) to either RDV or RDU. When a busy signal
(P SCU or P SCS) enters the microprocessor (IC508), that
band is switched to when CTCSS is on. When both bands —
are busy, the circuit is switched every 500 ms.
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output)
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Fig.11 Cros point switch (RD system)

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"