Operating instructions, Zero adjust, Chapter 4 – Bird Technologies 6151A User Manual
Page 17

Chapter 4
Operating Instructions
WARNING
Exposure to RF power radiation and the possibility of RF shock or burns exists with some
operating conditions. Always be sure to turn off transmitter when connecting or
disconnecting wattmeter. When Plug-In Element is removed from the RF line socket, the
line section center conductor is exposed. Do not put fingers or other objects into this
Plug-In Element socket while RF power is applied.
WARNING
Never attempt to disconnect any RF equipment from the transmission line while RF power
is being applied. Leaking RF energy is a potential health hazard.
Operating
Precautions
1.
Carefully check the condition of the RF cable and connectors
used in the circuitry to the Model 6151A.
2. The RF cable lengths, adapters and connectors should be
kept to a minimum. Type N or other constant impedance
connectors and adapters should be used throughout.
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 between 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 several times to eliminate possible error
from transmitter variations.
Zero Adjust
Place the Model 6151A Termaline Wattmeter in a position where the meter can be
easily read while the transmitter is being adjusted. If the meter pointer does not
read zero under no-load conditions, 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 5.
Zero Adjust
Figure 5
Zero Adjust
7