Scenario 4 - New Bird on the Block

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

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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

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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.

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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.”

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TIDEMARK-2 Link Parameters

Orbital Position

Satellite	Orbital Slot	Azimuth (from VT-01)	Elevation
TIDEMARK-1	53°W	161.9°	34.2°
TIDEMARK-2	45°W	219.7°	26.3°

Frequency Allocation

Parameter	RF (MHz)	LO (MHz)	IF (MHz)
Beacon (Downlink)	4,180	5,250 (LNB)	1,070
Carrier (Downlink)	3,792	5,250 (LNB)	1,458
Carrier (Uplink)	8,020	7,000 (BUC)	1,020

Note

TIDEMARK-2 frequencies differ from TIDEMARK-1. Verify each value against the reference table - don’t assume parameters carry over between satellites.

Modem Configuration

Direction	Frequency (IF)	Bandwidth	Modulation	FEC	Power
Receive	1,458 MHz	36 MHz	QPSK	3/4	—
Transmit	1,020 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	Narrow for CW beacon
RBW	1 kHz	Tight resolution
Reference Level	-90 dBm	Typical beacon level

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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.

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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 161.9°, El 34.2°

Phase 2: Antenna Slew

Command antenna to TIDEMARK-2:

• Set tracking mode: Program-track
• Select target: TIDEMARK-2
• Wait for slew to complete
• Verify position: Az 219.7°, El 26.3°

Caution

The antenna will slew approximately 58° in azimuth and 8° in elevation. This takes time - don’t interrupt the slew.

Phase 3: Beacon Acquisition

Verify antenna pointing with beacon:

• Configure spectrum analyzer for 1,070 MHz IF
• Set narrow span (10 kHz) and tight RBW (1 kHz)
• 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
• FEC: 3/4
• Verify carrier lock
• Confirm C/N ≥ 10 dB

Phase 5: Transmit Chain

Configure and enable transmitter:

• TX modem frequency: 1,020 MHz
• Bandwidth: 36 MHz
• Power: -7 dBm
• Modulation: QPSK
• FEC: 3/4
• Enable TX modem output
• Unmute BUC (before enabling HPA)
• Enable HPA output

Caution

Enable the transmit chain from input to output: BUC first, then HPA. An enabled HPA with no input signal can amplify noise or oscillate.

Phase 6: Full Duplex Verification

Confirm bidirectional link:

• Receiver: Locked with margin
• HPA: Enabled, proper backoff
• No alarms

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IF Frequency Calculations

Downlink (High-side LO):

IF = LO - RF

Example - Beacon:

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

Uplink (Low-side LO):

RF = LO + IF

Example - Carrier:

RF = 7,000 + 1,020 = 8,020 MHz

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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.