In both battle and test scenarios, naval ships need to be able to enter EMCON (Emissions Control) conditions. This can mean restricted emissions (no uniquely identifying transmissions) or no emissions at all (radio silence).

EMCON is used to ensure the enemy cannot triangulate the signal source and the ship using radio direction-finding techniques. Since RF transmissions are less common in the middle of the sea, even a very low power and short duration signal can stand out and make the ship an easily locatable target.

An additional reason for restricting emissions can relate to HERO (Hazards of Electromagnetic Radiation to Ordnance) requirements. This is known as HERO EMCON and is used to prevent ordnance systems from being inadvertently fired due to the effects of electromagnetic interference.

Rigorous procedures are used on board a naval ship to enforce EMCON as far as possible. However, for absolute verification of the radiation status of all shipboard emitters, it is necessary to directly monitor emissions. This can ensure that even a missed switch, malfunctioning equipment or an unauthorized cell phone does not give away the ship’s location.

In the dark, not in the dark

Don’t be in the dark about your emissions status, but be sure that your vessel is in the dark and undetectable. Our RFeye spectrum monitoring systems can verify that emissions are controlled. A single RFeye Node with a frequency range up to 18 GHz can be used to instantly verify that devices across the frequency range have been deactivated and provide a simple EMCON pass/fail according to emissions requirements.

If unwanted emissions are detected, handheld direction finders can then be used to locate any RF sources present onboard. This ensures that you can deny the enemy any way to use RF signals to identify your presence or determine your position.

It is also possible to install one of our Direction Finding Arrays aboard your ship. As well as EMCON verification, this system can be used to take advantage of any EMCON errors from enemy ships. The high sensitivity and fast sweep speeds of our systems mean even a very low power and short duration signal from the enemy can generate a bearing to their location.


Here a multi-mission DF Array has identified a signal on deck, while still delivering situational awareness with an enemy radio off the port side

Additional benefits of the solution

All our monitoring and geolocation systems can be used for any other spectrum monitoring needs at sea – for example, detecting and locating the source of any GPS jamming or spoofing that may be used to compromise your ship’s navigation systems.