Sea Tel DAC-2202, Installation And Operation Manual

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DAC-2202 Antenna Control Unit Installation
4-3
Refer to the Setup – Modem Connections, Setup and Test chapter for more information.
4.7.1.3. TS1 Control Interface Connections.
AGC & GND - External AGC, or Modem Lock, input.

External AGC input to the DAC-2202 must be 0 to 15 Volts DC analog signal, positive going
voltage proportional to satellite signal input level and must be real-time in its response to
antenna pointing.

External Modem Lock from a satellite modem is used as a positive ID that the antenna is on
the desired satellite.
This input is NOT used for Tracking purposes , it is only used for
satellite identification to acquire the correct satellite during search. To enable the external
modem input you must include a 2 in the SYSTEM TYPE parameter (If your system type is
presently 76 or 77, then change it to 78 or 79) and
NID MUST be set to 0000 .

Connections - The modem lock signal connects to EXT AGC and a ground reference
from the modem. The expected signal from the modem allows 0VDC to +15VDC. Low
voltage indicates modem lock, high voltage indicates modem unlock.

Testing - The input connections from the modem can be tested by selecting the external
AGC input and monitoring the displayed value. To select external AGC, set the tuning
frequency to 0000. Normally, AGC readings below 2048 are considered a low condition
and indicate modem lock and AGC readings above 2048 are considered a high condition
and indicate modem unlock.
[If you find the AGC reading for locked and unlocked conditions need to be reversed you
must add 128 to your current SYSTEM TYPE parameter]
.
Turn tracking OFF when checking the external AGC inputs. Be sure to properly retune the receiver
frequency when you are finished testing the external input.

Operation - In NORMAL operation, AGC must be above Threshold AND external MODEM
Lock input must be locked to Track the satellite. If you are tracking a satellite signal and the
AGC is above threshold (Tracking light on solid) but the external AGC signal rises above 2.5
volts for more than 20 seconds (external MODEM input
UNLOCKED ) the ACU will
automatically retarget the selected satellite.
SW1 - Band Selection control output . This output is used to control below decks tone
generator(s), or coax switch(s), for band selection functions. The band selection control output is
driven by the band selected in the MODE – TRACKING display.
SW2 - The Blockage / TX Mute Control output is driven
by Blockage and RF Radiation Hazard functions. This
output will short to ground whenever the antenna is within
the programmed AZ LIMIT zone(s) or is Searching,
Targeting or is mispointed 0.5 degrees from satellite peak.
This output is commonly used to drive:
If your modem cannot use the Modem Console
Port connection you will have to provide a transmit
inhibit output from the ACU by connecting a SW2
wire connection to the modem to comply with FCC
Order 04-286 and WRC-03 Resolution 902
.

Dual or Quad Antenna Arbitrator coax switches in
dual antenna configurations. The coax switches
select which antenna is feeding signal to the
below decks equipment.

Mute the Transmit output of the Satellite Modem
used in TX/RX antenna configurations when the
antenna is positioned where people may be
harmed by the transmit power emanating from
the antenna (RF Radiation Hazard).

Mute the Transmit output of the Satellite Modem
used in TX/RX antenna configurations when the
antenna is mispointed by 0.5 degrees, or more,
and keep it muted until the antenna has been