Maintenance
19
Calibration Checks
Setup Test
Note:
This test determines if the wattmeter needs recalibration:
1.
The following equipment is required, connected in series with the Bird
4304A (Refer to
Figure
9
).
RF source
Low pass filter
Reference, known accurate, wattmeter
50
load
Cables
Note:
Keep all connections as short as possible to minimize mis-
match and insertion losses.
2.
Set the RF source to produce a signal with power in the upper one-third of
the scale for each power range.
3.
Compare the reading on the Bird 4304A with the reference wattmeter.
Note:
If the unit is outside the stated accuracy range, return it to
a Bird Service Center for calibration.
Figure
9
Calibration Check Setup
Calibrating a Bird Element 4304A-1
Required Equipment
RF source capable of 100W from 25 MHz to 1000 MHz
RF source capable of 500 W at 405 MHz
Power standard
Model 4304A Wattmeter
1.
Remove the rear panel from the 4304A to access the adjustment
potentiometers.
