MFJ-925 Super-Compact IntelliTuner Automatic Antenna Tuner
Instruction Manual
©
2006 MFJ Enterprises, Inc.
1
The Basics
Introduction
The MFJ-925
IntelliTuner
TM
lets you rapidly tune any unbalanced or single-wire antenna automatically.
MFJ's exclusive
InstantRecall
TM
,
IntelliTune
TM
and
AdaptiveSearch
TM
algorithms give you fast automatic
tuning with more than 20,000 non-volatile
VirtualAntenna
TM
memories. The antenna has eight banks of
memory; with over 2500 non-volatile memories for tuner settings.
The tuner includes a highly efficient switching L-network with wide matching capability, 1.8 to 30 MHz
coverage, a radio interface port, and heavy-duty 10 amp/1000 volt relays. It is rated at 200 watts
SSB/CW.
A maximum of 256 values of inductance and 256 values of capacitance are available. With the
capacitance switched between the input and output side, this provides a total of 131,072 L/C tuning
combinations. The nominal tuning ranges are 0 to 24
μ
H and 0 to 3900 pF.
All MFJ
IntelliTuners
TM
learn and remember. When you transmit, they automatically adjust for minimum
SWR and remember the frequency and tuner settings, safely stored in non-volatile memory. The next
time you operate on that frequency (or close to it) and antenna, these tuner settings are instantly restored
and you’re ready to operate in milliseconds. The antenna has four banks of memory, which can learn and
remember more than 2500 frequencies and tuner settings.
When you key your transmitter, MFJ’s
InstantRecall
TM
checks its memory to see if you have operated
that frequency before. If so, tuning is instantaneous and you’re ready to operate. If not, MFJ’s
IntelliTune
TM
algorithm (based on MFJ’s famous SWR Analyzer technology) kicks in. It measures the
complex impedance of your antenna. Next, it calculates the components it needs and instantly snaps them
in. Finally, it fine-tunes to minimize SWR, and you’re ready to operate--all in a fraction of a second.
If the antenna impedance is not within the tuner’s measurement range, MFJ’s
AdaptiveSearch
TM
algorithm goes into action. Frequency is measured and relevant components values are determined. Only
those values are searched for fast tuning. If it still cannot find a match, the search is performed again
using a different search pattern.
All MFJ’s
IntelliTuners
TM
support radio tuner interfaces that are compatible with Alinco EDX-2 tuner,
Icom AH-3 and AH-4 tuners, Kenwood AT-300 tuner, and certain Yaesu radios with CAT system.
Optional interface cables MFJ-5114A (for Alinco), MFJ-5114I (for Icom), MFJ-5114K (for Kenwood),
MFJ-5114Y and MFJ-5114Y2 (for Yaesu) are available from MFJ Enterprises, Inc.
The tuners enter a “sleep” mode when idle and when no transmit signal is present, turning off the
microprocessor clock to avoid the generation of spurious signals.
Summary of Contents for MFJ-925
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