MFJ IntelliTuner -994B, Инструкция по эксплуатации

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MFJ-994B IntelliTuner Automatic Antenna Tuner Instruction Manual
©
2004-2010 MFJ Enterprises, Inc.
14
Operation
Manual Tuning
Manual tuning may be used to “touch up” the tuner’s settings. For example, if the target SWR is set at
the default of 1.5, the tuner will stop when a match of 1.5 is found. In all cases, manual tuning gives the
user control of the tuner if desired. Manual tuning should always be done at low power, and is
accomplished by using the [C-UP], [C-DN], [L-UP], and [L-DN] buttons. Since it is not known if more
or less capacitance or inductance is needed, manual tuning must be by trial-and-error. As an example, to
manually tune capacitance, press [C-UP] one time, and the reflected power will indicate if [C-UP] was the
right “direction.” If it was, press [C-UP] again and observe reflected power. If not, press [C-DN] twice
(once to return to the original setting of C, and once for one click past it).
Manual tuning of inductance is similarly accomplished, using [L-UP] and [L-DN]. Since the capacitance
and inductance are interdependent, some back-and-forth between the two may be needed, just as in a
conventional tuner with knobs.
Pressing [C-UP] and [C-DN] simultaneously moves the capacitance back and forth from one side of the
inductance to the other. Factory default is with the capacitance on the transmitter side. To move the
capacitance to the opposite (antenna) side, press [C-UP] and [C-DN] simultaneously. The reflected
needle will bounce to 5-watt mark. Press [C-UP] and [C-DN] simultaneously again to return the
capacitance to the transmitter side (and the forward needle will bounce to 30-watt mark to indicate the
change). A general rule of thumb is that loads with impedance higher than 50 ohms call for the
capacitance on the antenna side; loads lower than 50 ohms call for the capacitance on the transmitter side.
Pressing [C-DN] and [L-DN] simultaneously or pressing [TUNE] quickly places the tuner in bypass
mode; i.e. zero inductance and zero capacitance. RF from the transmitter goes directly to the antenna
with no matching. The reflected needle bounces to 20-watt mark to indicate the bypass mode.
Pressing [TUNE], [C-DN] and [L-DN] simultaneously overwrites the tuner memory with the current
tuner setting. Settings with SWR greater than 3.0 will not be stored. Both forward and reflected needles
go to full scale to indicate memory overwrite.
Component Limit
The upper limits of inductance (L) and capacitance (C) are factory-limited according to frequency and
maximum power rating; i.e., higher frequencies need less inductance and less capacitance when the L-
network is properly tuned. Pressing [C-UP] and/or [L-UP] allows capacitance and inductance to be
increased only to these limits. When a selected capacitance or inductance is higher than its allowed limit,
and the frequency is changed, that selection is automatically reduced to the value of its limit. These limits
are used to prevent matching of extreme load impedance outside the tuner’s specification, which may
result in excess voltage and/or current across the tuner’s components.