MFJ-1040B INSTRUCTIONS
MFJ-1040B INSTRUCTIONS
MFJ-1040B INSTRUCTIONSMFJ-1040B INSTRUCTIONS
The MFJ-1040B Deluxe RF Preselector II is a high gain RF
amplifier which covers 1 to 54 MHz in 4 bands. The unit has
switching capability to select one of two receivers and one of two
antennas for added versatil ity. There is also a relay which
automatically bypasses the amplifi er for use with tran scivers up
to 350 watts PEP input and has in added SWR of less than 1.2:1
maximum. The amplifier is bypassed when transmitting or when the
relay line is grounded.
INSTALLATION
1. Connect the antenna(s) t o the antenna termina ls. For each of
the antenna inputs there is a phono connector and a SO-239 coax
connector in parallel.
2. Connect the radio(s) to the receiver terminals. Each receiver
output has a phono connector and a SO-239 connector in parallel.
'
3. Connect the MFJ AC adapte r or a 9 to 18V DC
supply
to the
power jack. The tip of the 2.5mm subminiature jack is
positive.
4. If the MFJ-1040B is to be used with a transceiver, the MFJ
10480 may be operated one of two ways:
A.If automatic bypass (VOX
operation) is desired no
type
additional connections are needed.
B.If push-to-talk operation is desired connect the relay phono
jack to an auxiliary relay contact on the transceiver (such as
a relay line for a linear a mplifier). The auxillary contact
must ground the relay contact on the MFJ-10408.
OPERATION
1. Select the proper antenna and receiver with the appropriate
switches.
Turn the bandswitch to the proper frequency range, turn the
gain to maximum.
3. Turn on the MFJ-1040B. NOTE
when it is tur ned off.
2.
, The MFJ-1040B is bypassed
.
4. Turn the TUNE knob for m aximum signal. N0TE: The tuning
dial and receiver should re ad close to the same frequency. If
the dial is much different, you may be tuned to a receiver
image. Tune the preselector tuning dial to where the receiver
dial's frequency is clos e to the sam e frequ ency when t uned for
maximum gain. NOTE: The scale on the TUNE control is an
1
approximated marking. It may not indicate the exact frequency
shown on the receiver, however it should be relatively close.
5. If the unit is used with a transceiver in the RF sense
in
not
bypass mode (push to talk relay connection
delay co ntr ol so the re la y op er ate s t o r ece iv e in a convenient
time after the transmission (this is a VO X ty p e o f op e ration). If
the MFJ-1040B is used with an AM or FM rig the delay may be set
very short (0) because a carrier will be present throughout the
transmission. For SSB or CW , the delay should be set so that the
relay is energized between syllables or CW characters. When power
is disconnected or turned off, the MFJ-1040B is automaticall y
bypassed. If the relay line is used, there is no delay of the
amplifier when you go to receive.
6. If the preamplifier has problems with very strong signals
interfering, decrease the gain or push the 20 db attenuator to
reduce the interference.
MFJ-1040B
SCHEMATIC DIAGRAM
used), set th e
automatic
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