Satellite Interference Operator Playbook: 6 Common Scenarios and How to Fix Them

Operator Playbook: How to Use This Section

This playbook gives copy-pasteable SOPs for the interference cases you'll see most often. Each scenario follows the same pattern:

• Symptoms: What you'll see in NOC tools and from customers
• Immediate actions (0-15 min): How to stabilize service fast
• Investigation (15-120 min): How to confirm the interference type
• Mitigation and recovery: How to fix it
• Prevention: What to change in design and process

Most interference in SATCOM is unintentional—bad pointing, bad cabling, wrong power, nearby RF systems—not mystery jammers.

Standard Interference Response Pattern

Regardless of scenario, operators should run this baseline checklist:

Stabilize

• Confirm impact scope: single terminal, beam, transponder, or fleet?
• If a handful of terminals: mute the worst offenders (highest EIRP or visibly distorted carriers) first
• If a whole beam or transponder is affected: consider traffic re-routing if you have protection capacity

Classify

• Is the issue downlink (your receive chain seeing noise) or uplink (you or another user are polluting the transponder)?
• Is it continuous (always present), intermittent, or bursty or pulsed?
• Does it track one antenna (local issue) or whole network (space segment or wide-area RF)?

Coordinate

Loop in your satellite operator's NOC or ISOC early for:

• Cross-checks on other customers
• Carrier ID or geolocation support to identify misbehaving uplinks

If you suspect terrestrial systems (5G, radar), coordinate with spectrum regulators or MNOs via the sat operator.

Document

Capture: time ranges, affected carriers, spectra screenshots, modem logs, weather, any recent configuration changes. Tag and store as a repeatable pattern—feed back into your internal interference fingerprints library.

Scenario 1: Adjacent Satellite Interference (ASI), GEO Ku, Ka or C-Band

Objective: Restore link quality when your antenna is picking up energy from one or more neighbour satellites in the arc.

Typical Symptoms

• Degraded C/(N+I) on specific downlink carriers, worst when:
  • Weather is clear (rules out rain fade)
  • Neighbour satellites are heavily loaded
• Problems concentrate on small dishes (45-65 cm) and mobile VSATs
• QoS drops when a new adjacent satellite enters service or turns on carriers in co-frequency, co-coverage, co-polarization

Immediate Actions (0-15 Min)

Confirm it's downlink ASI, not local noise:

• Compare multiple terminals on different satellites from the same site
• If only one orbital slot is affected, suspect ASI

Check dish pointing quickly:

• Use available pointing or quality metrics (modem Eb/N0, STB bar)
• If you can safely adjust, try fine azimuth or elevation tweaks of ±0.2-0.3° while watching C/N (don't over-rotate)

Escalate to satellite operator:

• Ask if there were recent activations or power changes on adjacent satellites

Investigation (15-120 Min)

Step 1: Characterize the interference

• Capture before and after spectra around the affected carrier
• Identify whether you see:
  • A clear adjacent carrier bleeding in
  • A broad noise skirt from a saturated carrier on a neighbour

Step 2: Dish and RF checks

Verify:

• Antenna size and feed type against link budget assumptions
• Mounting hardware (no loose clamps or bent mounts)
• RF chain losses and LNB config

For installations using sub-1 m dishes, note that beamwidth is wide enough that C/(N+I) is often dominated by ASI, especially with 2-3° orbital separation.

Step 3: Coordination with sat operator

Request:

• EIRP maps of your satellite and adjacent satellites
• Coordination limits and any known hot-spots in your region
• Confirmation whether you're operating near co-frequency, co-polarization beams from neighbours

Mitigation and Recovery

Tactical fixes:

• Slightly de-point the antenna toward the desired satellite to reduce gain toward the stronger interferer (as advised by the sat operator)
• If available, switch to a larger dish or higher-gain antenna, which improves on-axis versus off-axis discrimination and boosts C/(N+I)
• If you have dual-satellite options for the same service, move affected traffic to a less crowded orbital slot

Network-level actions:

Work with the sat operator to:

• Move sensitive carriers to different transponders or frequencies further from the neighbour's high-power carriers
• Adjust power and roll-off to meet coordination limits while maintaining service

Prevention

During network design and procurement:

• Include explicit ASI margin in link budgets for small dishes at 2-3° slot spacing
• Select antenna sizes and feed patterns based on documented C/(N+I) versus dish size and orbital separation tables or tools

Operationally:

• Maintain a database of adjacent satellite plans (current and future) in each coverage region and track changes
• Standardize installation best practices and post-install verification (spectrum analyzer or equivalent)

Scenario 2: Cross-Polarization (Xpol) or Mispointed Antenna

Objective: Restore orthogonality between polarizations and clean up cross-pol interference caused by incorrect feed or antenna alignment.

Typical Symptoms

Satellite operator or NOC reports:

• High XPI or Xpol leakage from your terminal or beam

You see:

• Lower C/N with a ghost of the opposite polarization on the same frequency

Root cause is usually misaligned ground antennas or poor installation.

Immediate Actions (0-15 Min)

• Mute or back-off suspected offending uplinks if possible
• If you have a beacon or test carrier:
  • Lock on to it and freeze all non-essential changes until pointing and polarization are verified

Investigation (15-120 Min)

Step 1: Verify polarization settings

Confirm configured polarization (H/V, LHCP/RHCP) in:

• Modem
• Upconverter or RF chain
• Antenna feed assembly

Step 2: Xpol alignment procedure (linear pol)

Follow sat-operator guided peak and pol process:

• Peak antenna in azimuth and elevation
• Rotate the feed or pol angle to maximize desired pol and minimize orthogonal pol—typically targeting greater than 30-40 dB isolation on the satellite side

Step 3: Hardware checks

Inspect:

• Feed horn, polarizer and OMT for mechanical shift, corrosion, water ingress
• Mounting hardware for mechanical slop (wind-induced rotation)
• Any recent work at the site (tower climb, feed swap, repaint)

Mitigation and Recovery

Once correct polarization is confirmed:

• Re-enable uplinks at reduced power, then step up while the operator monitors XPI and ASI
• For sites that chronically drift, add mechanical locking (better clamps, anti-rotation brackets) or replace weak mounts

Prevention

Make Xpol verification a hard requirement for:

• New installs
• Moves or re-points
• After any tower work or feed service

Use documented procedures similar to those recommended by operators and equipment vendors for uplink and downlink polarization alignment.

Periodically run network-wide Xpol audits, prioritizing:

• Sub-1 m dishes
• Mobile or maritime terminals
• Harsh environments (high winds, extreme temperatures)

Scenario 3: Uplink Overpower or Dirty Carrier From Your Network

Objective: Stop one of your terminals from over-driving the transponder and creating ASI, XPI, or intermod products.

Typical Symptoms

Satellite operator reports:

• Overpowered carrier at [freq], your network ID

On your spectrum view:

• Carrier looks wider or distorted versus nominal mask
• Neighbour carriers show raised noise floor or visible intermod spur lines

Often triggered by:

• Misconfigured output power
• PA in compression
• Multiple carriers on one PA without enough back-off

Immediate Actions (0-15 Min)

• Mute or sharply back-off the suspected carrier
• If multiple terminals share the same transponder:
  • Use Carrier ID or terminal IDs where available to identify the offending remote

Investigation (15-120 Min)

Step 1: Confirm configuration

Check:

• Assigned EIRP or power back-off versus link budget
• Modem output level, upconverter gain, and PA drive settings

Step 2: PA linearity

Run a local output power sweep or intermod or 1 dB compression test where possible to verify the PA is not being over-driven.

Step 3: Cabling and combining

Inspect:

• IF or L-band cabling for poor terminations or wrong connections
• Any multiplexers or combiners that might be feeding unexpected signals back into the uplink chain, causing forwarding interference

Mitigation and Recovery

Restore uplink with:

• Proper power calibration (under sat-operator supervision for shared transponders)
• Correct back-off for multi-carrier PAs

If PA hardware fault is suspected:

• Swap to a known-good PA and re-verify mask and EIRP with the satellite operator

Prevention

Enforce mandatory power-up procedures:

• No transmission until sat-operator gives go-ahead on power and mask

Keep a power and EIRP history per site:

• Deviations from the baseline should trigger automatic alerts

Periodically test PA linearity and document 1 dB compression points for typical operating conditions.

Scenario 4: Terrestrial 5G, Cellular, FM or Radar Interference (C-Band and S-Band)

Objective: Protect satellite downlinks from strong nearby terrestrial RF systems using adjacent or overlapping spectrum.

Typical Symptoms

Degraded C/N on specific C-band downlinks, often:

• Worse at certain times of day (busy hours for 5G or radar)
• Localized to sites near cities, airports, ports, or broadcast towers

Spectrum analyzer shows:

• Strong carriers or wideband noise in bands like 3.3-3.8 GHz (5G), FM, or pulsed radar sitting adjacent to or within your receiver's front-end bandwidth

Immediate Actions (0-15 Min)

• Confirm the issue is local to one or a few sites (not fleet-wide)
• If possible, temporarily:
  • Rotate the antenna slightly to see if interference level changes (suggesting local source)
  • Insert any available bandpass filter ahead of the LNA or LNB

Investigation (15-120 Min)

Step 1: Characterize the interferer

Use a real-time spectrum analyzer (RTSA) to:

• Identify signature (OFDM 5G, pulsed radar, FM)
• Measure power levels versus your receiver's linear range and recommended max input (e.g., -60 dBm)

Step 2: Direction finding

Use RTSA plus mobile interference hunting tools to localize the source if multiple potential emitters are nearby.

Step 3: Site audit

Inspect:

• Filter installation (waveguide seals, flanges, gaskets) for RF leakage
• Nearby RF infrastructure (new cell towers, radars, microwave links, broadcast sites)

Mitigation and Recovery

• Install or optimize high-rejection bandpass filters at each affected site
• For severe cases:
  • Re-locate the antenna to a more shielded position
  • Adjust antenna height or azimuth to reduce line-of-sight to the interferer
• Coordinate with regulators or terrestrial operators:
  • Provide measurements and request power reductions or alternative configurations where rules support it

Prevention

• Include RF environment surveys in site selection and acceptance
• Keep a register of nearby spectrum licenses (5G, radar, broadcast) and track changes
• When new terrestrial services roll out, plan pre-emptive filter upgrades and spectrum clearing campaigns

Scenario 5: Intermittent Aircraft or Radar Interference

Objective: Recognize and manage intermittent, often pulsed interference that can be mistaken for random outages.

Typical Symptoms

Brief but recurring C/N dips or packet loss:

• Correlate with flight paths (near airports) or ship movements (coastal radars)

Spectrum shows pulsed signals in bands adjacent to your downlink (e.g., radar in 2-4 GHz S-band, aircraft altimeters near 4.2-4.4 GHz).

Immediate Actions (0-15 Min)

Confirm pattern:

• Compare to known air traffic times or radar sweep patterns

If the site is highly critical:

• Consider temporary power increase (within limits) or additional coding margin until a structural fix is in place

Investigation and Mitigation

• Use RTSA with pulse analyzer options to characterize radar signatures
• If correlation is strong (e.g., near an airport):
  • Coordinate with relevant authorities and sat operator to:
  • Adjust frequency plans or
  • Implement directional filtering or shielding and improved LNA front-end protection

Prevention

• Mark high-risk RF zones in your planning (airport or port proximity)
• Deploy more robust RF chains and filtering by default at those locations

Scenario 6: Unknown Interferer or External Uplink (Piracy, Misconfigured Third-Party)

Objective: Rapidly determine if interference is coming from an external uplink and hand it off to the satellite operator's mitigation process.

Typical Symptoms

Your NOC and terminals see:

• New, unexpected carriers on the transponder
• Or modulation you don't control overlaying your band

Satellite operator confirms:

• The source is not one of your registered terminals

Immediate Actions (0-15 Min)

Protect your services:

• Move critical carriers away from the interferer if possible
• Adjust power and coding to maintain robustness while the operator investigates

Operator Coordination

Provide to the sat operator:

• Spectrum snapshots
• Time ranges and affected frequencies

The operator will typically:

• Use geo-location tools and/or Carrier ID databases to identify the source
• Issue bogey messages, request uplink mutes or adjustments, and, if needed, involve regulators

Prevention

Ensure all your terminals:

• Are properly registered with the sat operator
• Use Carrier ID when available

Participate in industry-wide interference reporting and coordination bodies, since effective mitigation in these cases depends on shared information.