DRAKE SCT3860 Service manual
The transcoder then applies cable environment FEC to
this stream and remodulates using QAM modulation that
occupies a nominal 6 MHz wide cable channel slot. QAM
modes up through 1024QAM are supported.
The RF upconverter then upconverts the IF QAM signal to
the selected output channel - any standard EIA, IRC, or
HRC CATV channel or a broadcast off-air channel
frequency in the range of 54 to 860 MHz.
Bandpass flatness and phase noise are very closely
controlled in the SCT3860 to insure a high MER and S/N
ratio of the output signal. This insures that the transcoder
will not introduce a source of errors into the distribution
process. Because the MPEG2 transport stream informa-
tion is not modified by the transcoder, all encryption,
authorization, and program guide information is passed
on to the CATV set top box, unchanged.
GENERAL DESCRIPTION
The R.L. Drake model SCT3860 is a
professional quality, modular, digital headend component
providing QPSK or 8PSK input to QAM transmodulation
and RF upconversion functions in a single module. Up to
ten SCT3860 modules and a power supply module can
be accommodated in the RMT150 rack mounting tray,
occupying only a 2 unit (3.5”) high rack space. The
SCT3860 can transcode DigiCipher II or DVB digital
satellite signals, included those with advanced turbo
satellite FEC modes, outputting QAM modulation.
The SCT3860 accepts L band RF inputs between 950
and 2150 MHz from the LNB at the satellite dish. The
transcoder demodulates the selected satellite QPSK or
8PSK signal. The forward error correction (FEC) imbed-
ded in the data stream is used to help retrieve an error
free digital transport stream containing the desired digital
programming multiplex.
SCT3860 General Description / Installation and Mounting
INSTALLATION AND MOUNTING
Install the SCT3860 transcoders in the RMT150 rack
mounting frame. Slide each module into the tray so that
the "F" connector extends though the front panel hole, the
LED is properly aligned behind its front panel hole, and
the hook shaped projection on the bottom of the module
engages the rear of the mounting tray. Secure the
module with the supplied standard 1/2 inch "F" connector
mounting nut and nylon washer.
Similarly, mount the PS151 power supply in the RMT150
tray, making sure that the LCD display and control buttons
line up with their corresponding holes in the front panel,
and that the hook shaped projections on the rear of the
unit engage the rear of the mounting tray. Secure the
unit in place, with the supplied Philips head black
screws, from the front panel. Connect each SCT3860 to
the PS151 with the cable included with the SCT3860.
Each SCT3860 can connect to any one of the ten sockets
on the power supply. However, to minimize confusion, it
is suggested that the left most unit (as viewed from the
front panel) be connected to power supply socket
number 1, the second from the left to number 2, etc.
Connect the LNB signal to each SCT3860 module at the
front panel connector. Connect each SCT3860 RF output
"F" connector on the rear of the unit to the output com-
biner. The Drake model LBS2250 is a combination LNB
L band multiswitch/amplified splitter in addition to a CATV
output combiner. It provides these functions in only 1 RU
of rack space. Also, plug the cable from the front panel
fan module into the FAN POWER receptacle on the rear
of the power supply. Plug the line cord from the PS151
into the AC power source. SCT3860s can be mixed with
SCT1860s, SCT2860s, or SCT4860s and one PS151.
When installing the RMT150 tray of transcoders, it is not
necessary to leave a vertical airspace between the
transcoder tray and other equipment unless that other
equipment specifies that a space should be left open.
The air flow through the transcoders and power supply
has been designed to allow immediate adjacent
mounting of multiple RMT150 trays with SCT3860
transcoders and PS151 power supplies installed. Of
course, air spaces may be left in between RMT150s if
desired.
RF OUTPUT
POWER
RF OUTPUT
POWER
RF OUTPUT
POWER
RF OUTPUT
POWER
RF OUTPUT
POWER
RF OUTPUT
POWER
RF OUTPUT
POWER
RF OUTPUT
POWER
RF OUTPUT
POWER
RF OUTPUT
POWER
RS232 OUT
RS232 IN
1 2
3 4
5 6
7 8
9 10
FAN POWER
100 - 240 VAC
47 - 63 HZ, 125 W
+12
+5
TX
+3
GND
RX
ENTER
UNIT
SELECT
DRAKE TRANSCODER SYSTEM
ID 1.1
12.45 dB
L BAND INPUTS
SCT3860 Controls and Connections
FRONT PANEL CONTROLS AND INDICATORS
F1 - LCD Display - This displays the PS151 or selected
transcoder parameter and its setting.
F2 -UNIT SELECT (Left) and (Right) Buttons -
These select either the PS151 power supply or one of
ten SCT3860 transcoders. Information from the selected
unit will be displayed on the LCD display for parameter
adjustment. When either button is pressed once, the
LED of the selected transcoder will blink for about 3
seconds, but the unit selected will not change. The
second press within 3 seconds will increment ( )or
decrement ( ) to the next higher or lower numbered
unit. The PS151 power supply menu falls between
transcoder numbers 10 and 1.
F3 - (Left) and (Right) Buttons - Use the left or right
buttons to navigate from screen to screen to view a
parameter setting. This will not alter any settings. If in the
adjust mode, stop at the parameter you wish to adjust and
use the (up) and (down) buttons to adjust.
F4 - (Up) and (Down) Buttons - Use the up and
down arrows to adjust a parameter value when in the
adjust mode. When not in the adjust mode, pressing the
(up) button will display the software version readout,
and pressing the (down) button will display the QAM
modulation output baud rate readout.
F5 - ENTER - Use the ENTER button to enter the adjust
mode or to save and load a new setting or settings. Hold
for 2 seconds until the display flashes to enter the adjust
mode. After adjustment using the up or down arrow
buttons, press again to save and load the new settings.
You may save one parameter at a time after it is adjusted
or wait until all adjustments are made and press to save
and load all at once.
F6 - FAN - One of five front panel cooling fans. To ensure
proper cooling, do not block these openings.
F7 - L BAND INPUTS - These are the L band inputs from
the LNB. The level must be between -70 and -25 dBm.
The L band frequency range will be in the 950 to 2150
MHz range.
F8 - LED - The LED on each SCT3860 will blink on and
off for approximately 3 seconds when that unit is selected.
When in the adjust mode, it will blink continuously. When
in the normal mode, it will be lit continuously whenever
power is applied.
REAR PANEL CONNECTIONS
R1 - RS232 OUT - This RS232 serial connector can
connect to the RS232 IN connector on another rack
containing a PS150, PS151, or PS100 power supply
(included transcoders could be SCT860, SCT1860,
SCT2860, SCT3860 or SCT4860 transcoders), thus
allowing computer control of multiple racks of these units
with the same PC connection.
R2 - RS232 IN - Connecting this RS232 serial connector
to the serial port of a personal computer equipped with
Drake RS232 remote control software, allows remote
monitoring and programming of each transcoder. Alterna-
tively, can be connected to the Drake SCTeci. No connec-
tion is required for front panel control.
R3 - Fan Power- Connect the two conductor cable from
the front panel fans to this connector.
R4 - Power Out - These connectors are for connecting
the power cables from each individual SCT3860 to the
PS151 power supply. The other end of each cable can be
plugged into any one of the ten transcoders. However,
to minimize confusion, it is strongly suggested that the
left most unit (as viewed from the front panel) be con-
nected to power supply socket number 1, the second
from the left to number 2, etc. Do not attempt to use any
power supply other than this Drake supplied model.
R5 - Power In - This connector supplies power and
program control to the SCT3860. Connect a cable from
this connector to the appropriate connector on the PS151
power supply (see R4 above).
R6 - RF Output - This is the QAM output channel RF
output. The frequency range is between 54 and 864 MHz
depending upon the channel selected. The output level
is +25 to +40 dBmV, nominal, adjustable in 1 dB steps.
NOTE: Although the above discussions refer to the
SCT3860 transcoder modules, other Drake transcoders
may be mixed with SCT3860s in the same RMT150 rack
mounting tray. These include the SCT1860, SCT2860,
and SCT4860. The PS151 power supply/control module
will recognize each type of transcoder.
Also, SCT860 transcoders, although controlled by a
different power supply model, the PS100, can have the
RS232 control 'daisy chained' with the PS150 and PS151
controlled transcoders.
F1
F2
F3F4F5F6
F7
F8
ID 1.1
12.45 dB
ENTER SELECT
UNIT
DRAKE TRANSCODER SYSTEM RF OUTPUT
POWER
R1
R2
R3
R4 R5
R6
+12
+5
TX
+3
GND
RX
100 - 240 VAC
47 - 63 HZ, 125 W
FAN POWER
109
7 8
5 6
43
12
RS232 OUT
RS232 IN
SCT3860 Specifications
Specifications subject to change without notice or obligation.
SATELLITE INPUT
Frequency Range:
Tuning Increment:
Acquisition Range:
Input Level:
Input Impedance:
I/Q Phase Imbalance:
I/Q Amplitude Imbalance:
Mode:
FEC:
VITERBI Autoscan:
Turbo QPSK modes:
Turbo 8PSK modes:
Input Data Rate:
QAM OUTPUT
Output Impedance:
Output Level:
Display Error:
Level Adjustment Increment:
Frequency Range:
Frequency Plan:
Broadband Spurious:
Broadband Noise:
Phase Noise:
Frequency Stability:
QAM I/Q Phase Error:
Channel Amplitude Error:
Carrier Suppression:
MER:
Mode:
Symbol Rate:
FEC:
RS232 CONTROL
Data Link:
RS232 Input:
RS232 Output:
GENERAL
Operating Temperature Range:
Size:
Weight:
Power Requirement:
950 MHz to 2150 MHz.
500 kHz.
±5.0 MHz minimum.
-25 dBm to -70 dBm.
75 Ohms, return loss of 10 dB minimum.
<1 Degree.
<1dB.
QPSK, 8PSK.
DCII, DVB, advanced Turbo modes
1/2, 2/3, 3/4, 5/6, 6/7, 7/8 - DVB
5/11, 1/2, 3/5, 2/3, 3/4, 4/5, 5/6, 7/8 - DCII
1/2, 3/4, 2/3, 5/6, 7/8
2/3, 5/6, 8/9, 3/4, 4/5
2 Mbaud to 30 Mbaud.
75 Ohms, return loss of 10 dB minimum.
+ 25 to +40 dBmV, displayed.
± 2 dB maximum.
1 dB, nominal.
54 MHz to 864 MHz.
Standard, IRC, or HRC CATV channels
or off-air broadcast channels.
-60 dB, 5 MHz to 900 MHz.
-75 dBc, 6 MHz bandwidth.
-103 dBc/Hz @ 10 kHz offset.
± 5 kHz.
<1 degree.
<1 dB.
45 dB.
>40 dB, with blind equalizer.
16, 32, 64, 128, 256, 512, 1024 QAM.
1 Mbaud to 7 Mbaud.
ITU-T J.83 Annex A or Annex B.
4800 baud interface to PS151 via power
supply cable.
DB-9 connector on PS151 for connection
to modem or PC.
DB-9 connector on PS151 for connection
to additional transcoders.
00C to +500C, ambient.
1.1" W x 3.4" H x 13.25" D.
1 lb. 6 oz.
All voltages are provided by the Drake
model PS151 power supply. PS151
power requirement: 90 to 260 VAC / 150
W, maximum w. 10 transcoders powered.
SPECIFICATIONS
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