Electromagnetic Interference (EMI) at Shoalwater Bay Training Area (SWBTA)

Electromagnetic interference effects are occurring to inoculate ADF elements to the realities of operating with degraded communications and GPS. These effects include jamming the following radio frequencies:

• Global Navigation Satellite System (GNSS) GPS L1 and L2 (affecting positioning and timing synchronisation) 
• Military communications 30MHz to 88MHz 
• Military communications 108MHz to 512MHz 
• Unmanned Aerial Systems (UAS) 915MHz to 928MHz 
• UAS 2.4GHz 
• UAS 5.1GHz to 5.8GHz 

Only specific frequencies within the above bands will be jammed. The Defence Spectrum Office, in consultation with the Australian Communications and Media Authority is conducting analysis to confirm specific frequencies and bandwidth that may be jammed. 

GNSS jamming: 

There will be no spoofing of GNSS. 

GNSS jamming is assessed to be of greatest impact to commercial and civil aviation. GPS testing is scheduled as follows and may result in interrupted or unavailable GPS signal. 

GNSS jamming may occur at low power throughout the period 02 – 19 August 2026, with NOTAMs released 48 hours prior with specific detail. 

Pre-planned GNSS jamming at a higher power output will occur 17 – 19 August 2026, as follows: 

• Centred at S22 27.9 E150 08.8 or the RK VOR 332 degree radial at 56 NM. 
• Dates and estimated times (GMT (Z)): 
  • 17 Aug 26 0200Z – 0300Z (equipment testing and setup) 
  • 18 Aug 26 0000Z – 0100Z (GNSS jamming) 
  • 19 Aug 26 0000Z – 0100Z (backup day) 

Duration: 

Timings described in this AvSEF are indicative only and are subject to change, review NOTAMs for confirmed timings. 

Anticipated NOTAM: 

GNSS CAPABILITY SUBJ TO INTRP DUE INTERFERENCE WI 157NM RADIUS PSN 222754.00S 2500848.00E FM SFC TO 10000FT AND WI 249NM RADIUS PSN 222754.00S 2500848.00E FM 10000FT TO FL300 SFC TO FL300 FROM 08 170200 TO 08 190800 REPORT ANY SIGNIFICANT INTERFERENCE TO ATS FOR RELAY TO AND RESPONSE BY DEFENCE TEST CONTROLLERS. DEFENCE WILL RESOLVE INTERFERENCE WITHIN 10 MINUTES. 

The NOTAM previewed may change with little or no notice. Pilots are advised to check NOTAMs frequently for possible changes prior to operations in the area. NOTAMs will be published at least 48 hours in advance of any GPS tests. 

Pilots are encouraged to report anomalies to Air Traffic Services (ATS) in accordance with CASA’s published guidance on “Recognising, Mitigating and Adapting to GNSS Interference” (link below). As required, ATS will coordinate with Defence test controllers in accordance with the Manual of Air Traffic Services (MATS) section 5.1.11. 

Communications jamming: 

Electromagnetic interference jamming of military communications will occur at multiple areas throughout SWBTA. Frequencies jammed will be licensed to Defence; however, there may be some frequencies that are dual use. These frequencies will be identified and interrogated by the Defence Spectrum Office prior to jamming being approved. Jamming of communications will be at multiple periods throughout in the window of 02 – 18 Aug 2026. 

UAS jamming: 

Electromagnetic interference jamming of UAS communications frequencies will occur at multiple areas throughout SWBTA. Frequencies employed by most UAS are in the WiFi spectrum. UAS jammers may disrupt WiFi networks in vicinity of the jammers during periods of jamming. Jamming of communications will be at multiple periods throughout in the window of 02 – 18 Aug 2026. 

Expected effects on aviation operations: 

Aircraft operating within the notified area may experience intermittent degradation or loss of GNSS-derived position, navigation and timing information during periods of jamming. Depending on aircraft equipment, operating environment and proximity to the activity, operators may observe navigation uncertainty, degradation of GNSS-dependent capabilities, or associated cockpit alerts and warnings. Operators should consider the availability of alternative navigation and contingency procedures when planning operations during notified periods. There will be no intentional spoofing of GNSS signals associated with these activities. 

Safety and spectrum management controls: 

Defence has undertaken spectrum planning and technical analysis to minimise impacts on non-participating users while achieving essential training outcomes. Proposed frequencies, bandwidths and transmission parameters are subject to Defence spectrum management processes and coordination arrangements as required. Activities will be supported by NOTAM publication, ATS coordination and established cease-buzzer procedures. 

Propagation of electromagnetic interference effects: 

The propagation of radiofrequency energy is influenced by a range of factors including transmission characteristics, aircraft altitude, terrain and atmospheric conditions. As a result, electronic attack effects may extend beyond the geographic boundaries of SWBTA. Defence has sought to minimise the extent and duration of effects while achieving the required training outcomes. 

Potential operational impacts: 

Operators intending to conduct GNSS-dependent operations within the notified area during periods of activity should review applicable NOTAMs and assess the suitability of planned navigation, surveillance and operational procedures. The anticipated area of effect and activity periods will be promulgated through aeronautical information products. 

Aeronautical information: 

Final coordinates, dimensions, altitudes and activity periods will be promulgated through approved aeronautical information products, including NOTAMs. Operators should consult current aeronautical information during operational planning and execution. The draft NOTAM included in this consultation is provided for awareness purposes and remains subject to refinement prior to publication. 

Operational necessity: 

Contemporary military operations rely heavily on positioning, navigation, timing and communications systems. Training in a degraded electromagnetic environment is necessary to ensure personnel, systems and procedures remain effective when those capabilities are disrupted. The proposed activities are designed to achieve these training outcomes while applying appropriate safety, spectrum management and airspace risk mitigations. 

Cease Buzzer: 

Defence has arrangements in place to suspend GNSS jamming activities should an unexpected aviation safety concern be identified. Operators experiencing suspected interference should report the occurrence through ATS to enable assessment and coordination with Defence personnel. Specific cease-buzzer contacts and procedures will be promulgated through applicable NOTAMs. 

Contact details: 

During conduct of the activity 02 – 19 August, contact details regarding EMI are: 

Mr Jacob Marshall, 0439 035 118, jacob.marshall5@defence.gov.au 
Mr Matthew Brown, 0418 328 385, matthew.brown27@defence.gov.au