Technical information

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rather than use previously stored information. The default is: Tune
From Memory: [YES].
4.0 Tuning Process and Options
MicroTune™ Software
Copyright 1991-2001
The SG-239 MicroTune™ Software is unique software which allows
precise tuning of the digitally controlled π and L network to tune a
wide variety of antennas. The versatile MicroTune™ software offers
its user these special functions:
1. The coupler is activated whenever forward power is present.
2. In addition to sampling VSWR to determine if the coupler should
re-tune, frequency comparison is employed. This causes the coupler
to tune when ever the transmit frequency changes independent of the
VSWR reading.
3. Extensive tuning paths are used to test different antenna situations.
The initial tuning of a new frequency (or switched antenna) may re-
quire up to two seconds. Any further tuning is accomplished in a mat-
ter of milliseconds if jumper JP3 (Tune From Memory) is in its de-
fault position.
4. Facilities and algorithms are used which enable accurate tuning at
the low end of the frequency band—even on shorter antennas than
previously possible.
5. The BITE (Built-In-Test-Equipment) Indicator Tune LED includes
a safety feature that alerts the operator to a mismatched condition,
with blinking indicators, when proper tuning conditions have not been
met. In this situation, the software will “time out” within 20 seconds
unless a new frequency is sensed, which will cause an immediate time
out, and the coupler will attempt to match the new frequency. The mi-
croprocessor of the coupler “wakes up” every time the coupler has
forward power. However, re-tuning takes place only if the frequency
has changed or the VSWR exceeds 2:1.
4.1 Program Description
When DC power is applied, the computer initializes the processor reg-
isters in accordance with the hardware. All tuning elements are then
SG-239 Manual
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