Bird Technologies 6156 - Manuale (Pagina 21)

Chapter 4
Operating Instructions
WARNING
Never attempt to connect or disconnect equipment
from the transmission line while RF power is being
applied. Leaking RF energy is a potential health
hazard.
Operating
Precautions
Before operating the equipment, perform the following
steps:
1. Carefully check the condition of the
RF cable and connectors used in the
circuitry.
2. The RF cable lengths, adapters and
connectors should be kept to a mini-
mum.
3. When other than 50 ohm connectors
are used, keep at the transmitter jack
only. This will keep the RF cable free
from standing waves.
Operator’s
Test for
Accuracy
Operating checks should consist mainly of comparison be-
tween this wattmeter and a Thruline Wattmeter or other
wattmeters of the same type. This will indicate an accuracy
of within ± 10 percent full scale due to the ± 5 percent full
scale limits of each instrument. Repeat the cross-check sev-
eral times to eliminate possible error from transmitter
variations.
Frequency
Response
These wattmeters are broad band instruments. Misreading
can occur with the presence of harmonics or spurious fre-
quencies. To prevent misreading due to harmonics, connect
a low pass filter between the transmitter and wattmeter. Do
not continue operation of the wattmeter when large spuri-
ous responses are present.
Zero Adjust
If the meter pointer does not read zero under no-load condi-
tions, turn the zero adjust screw (located below the meter
face) slightly to the right or left with a small screwdriver
until the pointer is exactly on the zero mark. Refer to figure
4.
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