Bird Technologies 4391A - Manual (Page 27)

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Figure 13 Maximum or Minimum Readings
Using the Peaking Aid
The peaking aid is useful for making adjustments to optimize any of the parame-
ters which the Model 4391A measures. After the mode is selected, press the
delta (
Δ) key momentarily. This blanks the least significant digit of the display,
and replaces it with a right-facing arrow head if the measured quantity is
increasing or a left-facing arrow head if it is decreasing. If there is no change, the
digit is left blank. To find a peak, begin making the adjustment in whichever
direction produces a right-facing arrow and continue slowly in that direction
until the arrow head turns around. At this point the peak has been reached. To
check to make sure the peak has not been passed, press the MAX key to read the
highest value read and release it to read the current value. The two should be
the same. Desired minimum levels (e.g. of reflected power or of SWR) are found
in a similar manner.
Figure 14 Peaking Aid (D)
Battery Care
With average use, the nickel metal hydride batteries in the 4391A will power the unit
for 12 hours before needing recharged. The 4391A will maintain rated accuracy until
all the decimal points light, indicating that recharging is required. To recharge, con-
nect AC power to the unit. To fully charge the batteries requires approximately 16
hours. To prolong the life of the batteries, it is recommended that you periodically
allow the batteries to discharge until the decimal points light before recharging. If
the batteries lose the ability to hold a charge they should be replaced. See
Chapter 5, Maintenance, page 17 for important precautions regarding static electric-
ity when opening the housing.