Operation; Power-Up; Basic Tuning Operation; Operation From The Icom Transceiver Front Panel - LDG IT-100 Operation Manual

Operation

Power-up

The IT-100 is powered by the transceiver over the radio interface cable. The IT-100 is "on"
when the radio is turned on, and "off" when the radio is off.

Basic Tuning Operation

The IT-100 is operated from the front panel TUNE button on the IT-100, or via the
TUNER/CALL button on the front of the transceiver. Two types of tuning cycles are available;
a memory tuning cycle and a full tuning cycle.
The memory tuning cycle attempts to tune quickly based on having previously tuned on the
present frequency selection. If the tuner previously was successful in tuning on the currently
selected frequency, the settings for that match will be loaded into the tuner relays, and checked to
see that an acceptable SWR match is found.
A full tuning cycle "starts from scratch" and begins a fixed tuning sequence where the IT-
100 rapidly tries varying combinations of inductance and capacitance values, and then zeroes-in
on the best match possible. When the tuning cycle is complete, if an acceptable match was
found, the inductance and capacitance settings are saved in a memory associated with the
selected frequency, so that they may be recalled quickly in the future via a memory tuning cycle.
In this manner, the IT-100 "learns"; the longer you use it, the more closely it adapts itself to
the bands and frequencies used. Most users will probably use memory tuning most of the time; it
takes advantage of any saved tuning settings, but automatically defaults to a full tuning cycle if
no stored data is available.
In both cases, at the end of the tuning cycle, the carrier is held for 1.5 seconds after tuning is
complete, so that the final SWR may be read on the transceiver's internal SWR meter or another
inline SWR meter, and the front panel LEDs will indicate the status of the tuning cycle.
The tuner may also be placed in "bypass" mode where it is electrically removed from the
antenna system.

Operation From the ICOM Transceiver Front Panel

To initiate a tuning sequence from the ICOM transceiver, press and hold the TUNER/CALL
button for one second. The radio will switch to CW mode, reduce power, and begin to transmit a
carrier. The IT-100 will begin a memory tuning sequence as described above. If an acceptable
SWR match is found in the memory tuning cycle, the tuning cycle ends. Otherwise, the IT-100
automatically begins a full tuning cycle in an attempt to find a good match. If the full tuning
cycle is then successful, the match is stored in a memory associated with the selected frequency.
When the tuning cycle is complete, an indicator on the display of the transceiver will show
that the tuner is active. This indicator varies by model; consult the transceiver owner's manual
for details on operation with an external automatic tuner.
To bypass the tuner via the ICOM transceiver front panel, press the TUNER/CALL button
momentarily. The Tuning LED on the IT-100 will blink once to indicate it is in bypass mode.
The tuning indicator on the front panel of the transceiver will also extinguish.
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