Bird Technologies AT-400 - Manual (Page 35)

Measure Match
23

NOTE: If an out of range value is entered, the minimum
(if under-range) or maximum (if over-range) value will
be substituted. If a maximum value that is lower than
the minimum value is entered, the cursor will blink
again on the minimum value waiting for a correct entry.
The actual range depends on the units selected.

NOTE: Using the arrow keys will keep you in the
acceptable range. If you are not sure if the larger value
should be at the top or bottom of the scale, press the
auto scale key to see where the software puts it.
Selecting the Sweep Type
Sweep types are continuous or single hold. Continuous will
sweep and update the trace automatically. Single hold will
sweep once and the trace will remain in the display. Each
time single hold is pressed, the trace is updated.
y Press the MENU key.
y Press the SWEPT FREQ key.
y Press the SWEEP TYPE key.
y Depending on desired mode press either SINGLE
HOLD or CONT key. HOLD will be displayed if single
hold is selected. The tester begins sweeping if
continuous is selected.
Saving a Trace
The AT-400 can store up to 12 traces. A saved trace can be
used to evaluate long term antenna performance, compare
performance under different conditions or for comparison to
another antenna. A saved trace is also a powerful tool in
limit testing (more about limit testing later in this section).
The information can later be uploaded to a PC using optional
interface software and the serial port. Traces are stored in
nonvolatile memory so they are not lost when the Antenna
Tester is turned off.
Since the reflection coefficient is the information actually
saved when saving a trace, and everything else is calculated
from that, you have some flexibility when using the trace for