Watkins-Johnson Company WJ-8711A, Installation, Operation And Maintenance Manual

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INSTALLATION WJ-8711A DIGITAL HF RECEIVER
2-6
2.2.4.2
SMO, Signal Monitor Output (A3J2) - The signal monitor output is a BNC female
connector, which provides a sample of the 2nd intermediate frequency, centered at 455 kHz with a minimum
bandwidth of 30 kHz at -6 dB and an inverted spectrum. The nominal output impedance is 50 ohms with
approximately 25 dB of gain from the antenna input. This output may be used by a signal monitor or other
ancillary equipment.
2.2.4.3
EXT REF, External Reference Input (A3J3) - This female BNC connector allows an
external 1 MHz, 2 MHz, 5 MHz, or 10 MHz reference input, having a minimum level of 200 mV rms into a
high impedance load, to be used as the time base for the receiver. The WJ-8711 automatically switches to
external reference operation upon sensing the external reference input signal (providing it is within the
specified limits).
2.2.4.4
IF OUT, Post-Filtered IF Output (A2J1) - This BNC female connector provides the post-
filtered IF output. The output is centered at 455 kHz with a bandwidth equal to the operator-selected IF
bandwidth. The minimum output level is -21 dBm (20 mV) into a 50 ohm load.
2.2.4.5
CSMA, Carrier Sense/Multiple Access Port (A2J2) - This mini-phone connector is used as
the interface port for Carrier Sense/Multiple Access (CSMA) remote operations. The connector's center
conductor carries the remote data while the sleeve is ground. To ensure electromagnetic compatability (EMC)
with other devices in accordance with IEC EMC standards, use a shielded twisted pair cable when interfacing
with the WJ-8711A through the CSMA port. See
Section V of this manual for details on the CSMA remote
interface and operations.
2.2.4.6
A2J3, RS-232C Serial Interface Port - This D-type, 25-pin connector is used as the
interface port for RS-232C remote operations. The RS-232C interface operates as a full duplex interface at a
selectable baud rate of 75 to 9600 bps. Pin 2 of this connector is the transmit data line (TXD), pin 3 is the
receive data line (RXD) and pin 7 is ground. See
Section IV of this manual for details on the RS-232C
remote interface and operations.
2.2.4.7
TB1, Audio Terminal Block (TB1) - This terminal block contains 13 terminals for
connection of various inputs and outputs of the receiver such as line audio outputs, speaker outputs, DC-
coupled audio output, remote signal strength indicator output, squelch output, and mute input. These input
and outputs at the terminals of A2TB1 are further described in the following paragraphs.
2.2.4.7.1
Line Audio Outputs (TB1 Terminals 1 thru 6) - Terminals 1 thru 6 of TB1 provide two,
center-tapped balanced line audio outputs. One of the line audio outputs (LINE A) is provided on the
combination of terminals 1, 2, and 3. Terminal 1 is the positive output (LINE A (+)), terminal 3 is the
negative output (LINE A (-)) and terminal 2 is the ungrounded center tap output (LINE A (CT)).
The other line audio output (LINE B) is provided on the combination of terminals 4, 5, and 6.
Terminal 4 is the positive output (LINE B (+)), terminal 6 is the negative output (LINE B (-)), and terminal 5
is the ungrounded center tap output (LINE B (CT)).
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