Scenario 4 - New Bird on the Block

Duration: 25-30 minutes Difficulty: Beginner Mission Type: Satellite Switchover

Shift Turnover Notes

Date: Wednesday, 1030 Local Station: Vermont (VT-01) Operator on Duty: You Supervisor: Charlie Brooks (present) Maine Station: ME-02 (Catherine Vega on station)

Halifax spacecraft ops just confirmed TIDEMARK-2 is ready for ground operations. The bird finished station-keeping about a week ahead of schedule - good problem to have.

ME-02 has primary on TIDEMARK-1, so there’s no customer impact while you work. Take your time with this one. Your first full satellite switchover.

— Charlie

Active Services

Satellite	Station	Customer	Status
TIDEMARK-1	ME-02	Teleport Services Inc.	Operational
TIDEMARK-2	VT-01	—	Pending activation

TIDEMARK-2 completed station-keeping at 45°W and the Halifax spacecraft team has handed over the communications payload to ground operations. VT-01 will establish the initial ground link.

Spacecraft Status

From: Marcus Chen, Halifax Spacecraft Operations Received: 1025 Local

“TIDEMARK-2’s station-keeping is looking good - we finished the last maneuver sequence yesterday and the payload’s been handed over to ground ops. She’s all yours now.

One thing to remember: TIDEMARK-2 is at a different orbital slot than TIDEMARK-1, so your look angles and frequencies will all be different. Don’t just copy what worked for the other bird.”

TIDEMARK-2 Link Parameters

Orbital Position

Satellite	Orbital Slot	Azimuth (from VT-01)	Elevation
TIDEMARK-1	53°W	153.2°	35.2°
TIDEMARK-2	45°W	143.4°	31.9°

Angles are the ACU’s program-track values (it reads about 153.2° on TIDEMARK-1). Both slots are east of Vermont’s 72.6°W, so both birds sit in the south-east sky; the slot farther east (45°W) sits further from due south and lower. The Overview card’s satellite angles can differ from the ACU by about a tenth of a degree (the ephemeris offset); that is inside the beam. The ACU’s POLARIZATION readout moves with the slot as well: about +18.8° on TIDEMARK-1 and +25.2° on TIDEMARK-2, the same sign and about 6° apart, because both slots are east of the station.

Frequency Allocation

Parameter	RF (MHz)	LO (MHz)	IF (MHz)
Beacon (Downlink)	4,180	5,250 (LNB)	1,070
Carrier (Downlink, TP-1)	3,792	5,250 (LNB)	1,458
Carrier (Uplink, TP-1)	6,017	7,000 (BUC)	983

Modem Configuration

Direction	Frequency (IF)	Bandwidth	Modulation	FEC	Power
Receive	1,458 MHz	36 MHz	QPSK	3/4	—
Transmit	983 MHz	36 MHz	QPSK	3/4	-7 dBm

Spectrum Analyzer Settings (Beacon Acquisition)

Parameter	Value	Notes
Center Frequency	1,070 MHz	TIDEMARK-2 beacon IF
Span	10 kHz (enter 0.01; the field is in MHz)	Narrow for CW beacon
RBW	Auto	About 30 Hz at a 10 kHz span: a narrow RBW lowers the noise floor under the CW line
Amplitude	Min Amp -115 dBm, Max Amp -35 dBm	The beacon reads about -43 dBm (within 2 dB) on the Peak readout next to Peak Search; the noise floor near -100 dBm stays clear of the bottom edge

Station Reference

Vermont (VT-01) - Current State

Equipment	Status	Notes
GPSDO	Locked	Timing reference stable
Antenna	Program-track on TIDEMARK-1	Will command to TIDEMARK-2
LNB	Powered, locked	LO: 5,250 MHz
BUC	Muted	LO: 7,000 MHz
HPA	Disabled	Enable after BUC unmuted
RX Modem	Configured for TIDEMARK-1	Reconfigure required
TX Modem	Idle	Configure for TIDEMARK-2

Maine (ME-02) - Reference

Equipment	Status	Notes
Full link	Operational	Primary on TIDEMARK-1

Catherine is maintaining customer traffic on TIDEMARK-1 while you complete the switchover.

Satellite Switchover Sequence

Standard switchover follows this sequence. Each phase must complete before the next.

Phase 1: Verify Current State

Before making changes, confirm:

Current antenna target: TIDEMARK-1
Tracking mode: Program-track
Antenna position: Az 153.2°, El 35.2°

Phase 2: Antenna Slew

Command antenna to TIDEMARK-2:

Set tracking mode: Program-track
Select target: TIDEMARK-2, then press Move to Target
Wait for slew to complete
Verify position: Az 143.4°, El 31.9°

Phase 3: Beacon Acquisition

Verify antenna pointing with beacon:

Configure spectrum analyzer for 1,070 MHz IF
Set narrow span (10 kHz, entered as 0.01 MHz), RBW on Auto, Min Amp -115 dBm, Max Amp -35 dBm
Confirm beacon signal at expected frequency

Phase 4: Receive Chain

Configure receiver for TIDEMARK-2 downlink:

RX modem frequency: 1,458 MHz
Bandwidth: 36 MHz, Modulation: QPSK (same as TIDEMARK-1)
FEC: 3/4

Phase 5: Transmit Chain

Configure and enable transmitter:

TX modem frequency: 983 MHz
Bandwidth: 36 MHz, Power: -7 dBm, Modulation: QPSK, FEC: 3/4 (carried over from TIDEMARK-1; check them)
Enable TX modem output
Unmute BUC (before enabling HPA)
Enable HPA output

Phase 6: Full Duplex Verification

Confirm bidirectional link:

Receiver: Locked on VT-01’s own carrier coming back down, C/N ≥ 10 dB
HPA: Enabled, proper backoff
No warning or critical alarms

IF Frequency Calculations

Downlink (LO above RF):

IF = LO - RF

Example - Beacon:

IF = 5,250 - 4,180 = 1,070 MHz

Uplink (LO above RF, lower sideband - the BUC panel shows LSB):

RF = LO - IF

Example - Carrier:

RF = 7,000 - 983 = 6,017 MHz

End of Briefing

ME-02 has TIDEMARK-1 covered. There’s no customer pressure on this switchover - just you, Charlie watching, and a satellite waiting for its first ground link.

Work through the sequence methodically. Verify each step before moving to the next. When you’ve got full duplex confirmed, Marcus will see it on the payload telemetry from Halifax.

This is your first end-to-end satellite switchover. Take your time and get it right.