Skanti TRP 9250, Техническое руководство, Страница: 153 / 289

PREVENTIVE MAINTENANCE
Due to the modern design of the TRP 9250 preventive maintenance can be reduced to a minimum
provided the equipment is correctly installed. To ensure maximum performance and minimum repair
trouble we recommend you to follow the below stated headlines for preventive maintenance.
1. The condition of the battery should be checked at frequent intervals. The battery must
always be fully charged and should be topped up frequently with distilled water (liquid
should be 5 to 10 mm above the plates).
2. Check the condition of antenna installation, groundconnection and cables at regular
intervals.
3. Keep antenna feed-through insulators clean and dry.
4. Ensure that no objects are obstructing the free airflow through the cooling channels of
the Transceiver Unit and keep the units free of dust accumulation to prevent overheating.
5. For cleaning use a damp cloth. Sticky dirt may be removed using a cloth with a weak
soap solution. Wipe off with a clean cloth.
Realignment of Master Oscillator 713
The Master Oscillator frequency should be checked at least once a year. The Master Oscillator
determines the exact transmit and receive frequencies of the equipment. All oscillators age very
slowly with time, typically with the highest drift rate the first year, approaching zero drift after some
years.
There are two methods to realign the Master Oscillator. The first method is the most accurate and
utilize a frequency counter. The adjustment should be performed by a qualified technician with the
necessary test equipment at his disposal. The second method is based on the reception of an AM
broadcast station or a CW signal with known good frequency accuracy. By using the User
Programmable function: "Prog" "31" "Enter" (Show Frequency Error) TRP 9250 is able to display
its own frequency error, which may be reduced to zero by simple adjustment of the Master Oscillator
frequency. This method eliminates the need for an accurate frequency counter.
Method 1: Realignment using a frequency counter.
1. Measuring Equipment:
1.1 Frequency Counter: Frequency range 100 MHz
Input impedance = 50 ohm
Sensitivity at least 0.2 Vrms
Accuracy better than 0.01ppm
2. Preparations:
2.1 Switch on the power at least 30 minutes before adjustment.
PREVENTIVE MAINTENANCE SERVICE
TRP 9250 TECHNICAL MANUAL 5-3