MLE-02 USER MANUAL
7
Note: DO NOT remove the 20A plug-in at Fuse position in any case. It is used for
over-current protection.
3.2 Installation
The amplifier can be placed on horizontally or hanged. For horizontal installation, generally it can
be placed in the cabinet. For outdoor installation, it can be hanged on something like telephone
pole. It just requires one steel wire to pass through two claws of the amplifier. If both amplifier
and cable are hanged outdoor, they will be in the environment with same temperature. If the
amplifier is in outdoor, while the cable is buried underground, they will be in the environment
with different temperature. In these two cases, the output level will change with the temperature,
just the range different. Generally, the attenuator can be adjusted to change the level.
3.3 Check Forward System
The adjustment of the amplifier includes input level setting, output level setting and output slope
setting, and attenuator adjustment or equalizer replacement if necessary. All test ports are -20dB
without 75Ω load. The steps are as below:
1. Open the upper cover, check whether the AC and DC voltage are normal. Connect the input
test port with field-intensity meter, and measure the input level and flatness of the pre-stage
amplifier module. It should meet the specification requirement. If the level is too high or too
low, the attenuation of the attenuator should be adjusted. Meanwhile, measure whether the
difference between the high-end and low-end level is less than 1.5dB, otherwise the
attenuator at the cable equalizer position should be changed. (The input level should be
around 72dBuV, which is not too high or too low). For example, the high-end input level
which the system record is +17dBmV, while the actual level is +23dBmV. Then the
attenuator must be adjusted to decay 6dB.
2. To test output slope, measure the difference between high-end and low-end gain. Choose the
fixed attenuator accordingly and plug in EQ (P2) position. If the measured value is small than
the actual one, then user should replace the slope plug-in with bigger tilt. (e.g. the actual
value is 10dB, then 4dB fixed attenuator can be used to work with the built-in fixed
attenuator which the tilt is 6dB.)
3. Measure the level at the high-end, which should be meet the specification requirement. (The
difference between the recorded value and measured value should be less than 1dB).
