Scenario 1 - First Fix
Shift: Wednesday 01 Sep 2027, 0000 Local (0600Z)
Station: Peterson Annex (PA-22), 22nd Electronic Warfare Squadron
Operator: You
Incident Cell Lead: TSgt Marisol Quintero (on the floor, working two other tickets)
Ops Director: Maj. Holt (0100Z sync - wants a fix, not a status)
Shift Turnover Notes
Section titled “Shift Turnover Notes”Swing shift logged the following at 2350Z:
Receive chain nominal, dish program-tracking SENTRY-7, service carrier locked at 1365 IF with C/N 12 dB. No alarms.
Customer opened a ticket at 2231Z for bursty packet loss on the TP-1 logistics net. We put the analyzer on RX IF with a max-hold trace and left it. Clear-write shows nothing wrong - the service carrier looks fine every time you look at it, which is the problem. Something in that passband is not there all the time.
Correlator is warmed up and SENTRY-9 is selected as the collector. It has not been tuned to anything. Do not retune the receive chain - the customer is live.
Active Services
Section titled “Active Services”| Satellite | Transponder | Customer | Service | Status at Turnover |
|---|---|---|---|---|
| SENTRY-7 | TP-1 (H) | JTF-South logistics net | 8 MHz QPSK 3/4 data carrier | Degraded - bursty packet loss |
| SENTRY-9 | - | 22 EWS (collector) | Sidelobe correlation pair for SENTRY-7 | Available |
The logistics net moves resupply manifests and medevac routing for a forward element. Forty seconds of loss every couple of minutes is enough to break every transfer they start.
Trouble Ticket
Section titled “Trouble Ticket”Ticket #: EW-27-0244
Opened: 2231Z by 22 EWS NOC (forwarded to PA-22 incident cell)
Priority: High
Customer Report:
JTF-S J6 reports TP-1 data carrier dropping in bursts since approximately 2140Z. Each burst lasts 30-45 seconds; interval between bursts roughly two minutes. Modem shows C/N collapse during bursts, recovers on its own. No weather in the beam. No changes on the customer side.
NOC Note:
Unable to confirm on a clear-write trace from the monitor site. Recommend max-hold on the victim downlink and a duty-cycle characterization. If it is an uplink interferer, PA-22 has the correlation pair to fix it.
TSgt Quintero (ops chat, 2358Z):
“It’s yours. I need three things before Holt’s 0100Z sync: what it is, how it behaves, and where it is. Find the carrier, time it, then go to the correlator and get me six clean captures - inside the on-window only. The correlator throws NO CORRELATION on any capture the interferer walks out of, and every failed capture is time we don’t have. Twenty-five kilometres or better. Log the characterization in the incident report as you go.”
SENTRY-7 / SENTRY-9 Operations Reference
Section titled “SENTRY-7 / SENTRY-9 Operations Reference”Both are inclined-orbit GEO birds - they stopped north-south station-keeping and now trace a daily figure-8 around their slots. From PA-22 they sit high and close together in the southern sky. Program-track handles the drift for SENTRY-7; the correlator handles it for both.
| Satellite | NORAD | Slot | Inclination | Az / El from PA-22 (0600Z) | Role |
|---|---|---|---|---|---|
| SENTRY-7 | 71001 | 100.2° W | 3.0° | 172.5° / 47.1° | Victim - carries the affected transponder |
| SENTRY-9 | 71002 | 98.1° W | 4.5° | 168.7° / 48.1° | Adjacent collector - hears the same uplink through its sidelobes |
Transponder Plan
Section titled “Transponder Plan”| Satellite | Transponder | Uplink Passband (MHz) | Translation (MHz) | Downlink Passband (MHz) | Polarization |
|---|---|---|---|---|---|
| SENTRY-7 | TP-1 | 5,990 - 6,030 (40 MHz) | -2,225 | 3,765 - 3,805 | H |
| SENTRY-9 | TP-1 | 6,232 - 6,268 (36 MHz) | -2,225 | 4,007 - 4,043 | H |
Anything uplinked into a TP-1 passband on the right polarization is relayed to the downlink, whoever sent it. TP-1 rejects cross-pol uplinks by roughly 28 dB.
Frequency Reference (PA-22 receive chain)
Section titled “Frequency Reference (PA-22 receive chain)”| Signal | Uplink RF (MHz) | Downlink RF (MHz) | LNB LO (MHz) | IF (MHz) |
|---|---|---|---|---|
| SENTRY-7 TP-1 service carrier | 6,010 | 3,785 | 5,150 | 1,365 |
| SENTRY-9 beacon (CW) | - | 4,005 | 5,150 | 1,145 |
| Unidentified carrier | (derive) | (derive) | 5,150 | (measure) |
Conversion notes for the incident report: IF = LO - RF (downlink) and uplink = downlink RF + 2,225. The correlator is tuned to the uplink frequency.
Peterson Annex Equipment Status
Section titled “Peterson Annex Equipment Status”| Equipment | State at Turnover | Notes |
|---|---|---|
| Antenna | Program-track on SENTRY-7 (71001) | Beacon locked, C/N 12 dB. Leave it |
| LNB | 5,150 MHz LO, powered, reference locked | 65 dB gain |
| GPSDO | Locked, 15 ns UTC accuracy | Timing reference for the correlator - verify it stays locked |
| Spectrum analyzer | RX IF tap, center 1,364 MHz, span 30 MHz, RBW 100 kHz | Trace 1 clear-write, trace 2 max-hold |
| Receiver modem 1 | 1,365 MHz, 8 MHz, QPSK 3/4 | Customer carrier - do not retune |
| BUC / HPA | Muted / disabled | PA-22 is receive-only for this incident |
| Geolocation console | Idle, SENTRY-9 selected | Untuned. 12 s integration window |
Correlator Reference
Section titled “Correlator Reference”The Geolocation console cross-correlates the SENTRY-7 downlink against the SENTRY-9 downlink and produces one TDOA/FDOA measurement per capture. It does not know what it is looking for until you tell it.
| Parameter | Value | Notes |
|---|---|---|
| Integration window | 12 s | Interferer must be transmitting for at least 70% of it (8.4 s) |
| Target frequency | Interferer uplink, MHz | Must be within half the interferer’s bandwidth of its center |
| Correlation bandwidth | Match the interferer | Accepted within a factor of two of the carrier’s occupied bandwidth |
| Adjacent collector | SENTRY-9 | Pre-selected |
| CAPTURE | One 12 s integration | Result line reports TDOA (µs) and FDOA (Hz), or NO CORRELATION |
| AUTO | Back-to-back captures | Retries through off-windows; each miss still burns 12 s |
| COMPUTE FIX | Solves all captures on the pair | Reports lat/lon and a 95% error ellipse as ±major×minor km |
Measurement noise on this pair is about 1.5 µs TDOA and 3 Hz FDOA. Six captures will get you inside 25 km most nights. The birds drift between on-windows, and every new window rotates the FDOA line of position - so captures spread across cycles tighten the ellipse faster than captures crammed into one.
Incident Report EW-27-0244 - Required Fields
Section titled “Incident Report EW-27-0244 - Required Fields”The Working Document panel holds the report. The cell needs these fields filled before the sync:
| Field | What the cell needs |
|---|---|
| 3. Frequency | Uplink center, MHz (with downlink RF and IF) |
| 4. Duty cycle | On-seconds / period, and the percentage |
| 5. Occupied bandwidth | MHz, from the analyzer |
| 6. Polarization | Uplink polarization and the basis for the call |
| 7. Fix | Lat/lon and the 95% error ellipse from COMPUTE FIX |
Field 6 is not a measurement you can make from a downlink. It is an inference from which transponder relayed the signal.
Capture Discipline Checklist
Section titled “Capture Discipline Checklist”Before the correlator
Section titled “Before the correlator”- Unidentified carrier observed on RX Analysis (max-hold holds it between bursts)
- IF center and occupied bandwidth read off the analyzer
- Uplink frequency derived (IF → downlink RF → +2,225 MHz)
- Cadence timed against the mission clock through at least two full cycles
On the correlator
Section titled “On the correlator”- Adjacent collector: SENTRY-9
- Target frequency: interferer uplink
- Correlation bandwidth: matched to the carrier, not the transponder
- Captures started only inside the on-window
- At least six successful captures, across at least two cycles
- COMPUTE FIX - ellipse reported
Report
Section titled “Report”- Fields 4, 5, 6 logged in the Working Document
- Fix and ellipse ready for the 0100Z sync
Escalation Guidelines
Section titled “Escalation Guidelines”Handle Yourself:
- Analyzer configuration, trace modes, timing the cadence
- Correlator tuning and capture timing
- Fix refinement (more captures, more cycles)
Tell Quintero:
- Fix will not close inside 25 km after twelve or more captures
- GPSDO drops lock (the correlator’s timing goes with it)
- Anything that touches the customer’s receive chain
Maj. Holt gets:
- A fix and an ellipse at 0100Z. Not a status.
End of Briefing
Section titled “End of Briefing”Somebody is keying an uplink into an allied transponder on a schedule, and they picked a duty cycle that hides from anyone who only looks at a live trace. The forward element on the other end of that carrier has stopped getting manifests.
You have the victim bird, the neighbor that hears the same uplink, a timing reference good to fifteen nanoseconds, and about an hour. Find the carrier, time it, and put an ellipse on the map small enough that a team can drive to it.
Quintero has two other tickets. Holt has a sync at 0100Z. The first fix is yours.