Operation; Basic Tuning Operation; Fully Automatic Memory Tuning; Force A Full Tuning Cycle - LDG RT-100 Operation Manual

OPERATION

Basic Tuning Operation

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. If this fails to find a good SWR match, then a full
tuning cycle begins.
A full tuning cycle "starts from scratch" and begins a fixed tuning sequence where the RT-
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 RT-100 "learns"; the longer you use it, the more closely it adapts itself to
the bands and frequencies used.
Whenever the RT-100 is powered up, it is in fully automatic Memory Tuning mode. This
means that any time RF is present, if the SWR detected is too high (above about 1.7), a memory
tuning cycle will automatically begin.
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.

Fully Automatic Memory Tuning

In order to begin a fully automatic memory tuning cycle, simply tune the radio to the band
and frequency desired, and, while the RT-100 is powered on, simply being transmitting. If a high
SWR condition is detected, the RT-100 Tuner will begin tuning. To watch the progress of the
tuning cycle, keep an eye on your radio's built-in SWR meter (or external SWR meter, if
applicable). The SWR needle will jump around for a bit and then will settle down to a low SWR
value. Once this happens, tuning is complete. If the tuner is tuning on a previously memorized
frequency, the tuning cycle will only last for a short instant while memory settings are recalled.

Force a Full Tuning Cycle

In some instances, you may wish to force the RT-100 to begin a full tuning cycle instead of
just the usual memory cycle. In order to do this, turn off power to the RT-100 (do this by
switching off power to the bias tee), begin transmitting a carrier, and while still keying the radio,
turn on power to the bias tee. Continue transmitting the tuning carrier until the SWR settles to a
low value.
When using the RC-100, transmit a carrier, press the tune button on the RC-100 for one
second then release. Continue transmitting the tuning carrier until the SWR settles to a low
value.
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