Measurement; Vhf Frequency - Furuno FM-8800D Service Manual

6.2 Measurement

6.2.1 VHF Frequency

As a reference oscillator for this equipment, TCXO (Temperature Compensated Crystal
Oscillators) is used. And there is no adjustment part of frequency.
Regulated range of frequency tolerance is within +10 ppm (+1.5 kHz approximately). If
the tolerance is more/less than +10 ppm, replace CPU board or Y1 (TCXO: 25.6 MHz)
on CPU board.
Connect the frequency counter as below. Read the frequency of the setup channel when
PTT switch is ON.
The frequency tolerance: within +10 ppm
Handset
The input to a frequency counter approximates the pick-up coil to a
dummy load or ANT coaxial cable and picks up TX frequency.
ANT
FM-8800S
FM-8800D
CH70 ANT
Fig. 6.2.1 Frequency Measurement
50 ohm
Power meter
6-3
6.2 Measurement
Antenna
50 ohm
Dummy
or
Freq. Counter