Expanse uses the Spectrum mod framework to provide a set of tools for stealth and detection.

Every ship and station produces signals based on their actions, and other players can upgrade their ships to enhance their ability to detect these.

For an overview of Signals in SDX2, watch the YouTube video below, or continue reading.

Signals

Detected signals show up on your HUD, indicating where the signal is coming from and how far away it is.

The information available for a signal depends on the received signal strength.

• Weak signals appear faint, showing their distance but no identifying information

• Strong signals are brighter, and show the associated faction and affiliation color

• Detailed signals also reveal the Ship Core of the signal source

Signal strength increases the closer to the source you get, with each strength bracket (Weak/Strong/Detailed) requiring half the distance of the previous.

For example, a signal that is Weak at 200km will be Strong at 100km and Detailed at 50km.

Signals come in two bands: Optical and Radio. Different types of signals can be detected through different means.

Emitting signals

The Signal HUD on the right-hand-side of the screen shows you the strength of signal that your ship is currently emitting.

The right side shows your Spherical signal - the ranges at which you can be detected in any direction. The smaller bright number is the range at which your signal appears Strong, and the larger faint number is the range at which your signal appears Weak.

The left side shows your Directional signal - the ranges at which you are visible from directly behind your drives.

Drives

The primary source of signal are drives. The more thrust you produce, the stronger the signal. Drive signals are Optical, and appear as a bright blue flare to anyone who detects them.

Unlike most signals, drive signals are stronger in the direction the drive is facing, forming a teardrop shape.

Drive signals extend up to 4x further in this direction, making you more visible to anyone you are burning away from or decelerating towards.

For more information, see Drives.

Power draw

Drawing power generates a Radio signal that scales with the amount of power consumed.

Antenna and beacons

All antenna and beacons output a Radio signal scaled to the broadcast range - a 100km beacon will appear Strong at that distance.

Detecting signals

You can improve your ability to passively detect signals by using different Detector blocks. Different detectors improve detection of different signal bands, and have varying sensitivities and constraints.

Baseline (1.0x)

All signal ranges displayed on the HUD are calibrated to a Baseline (1.0x) detection sensitivity. Baseline detection capability can be achieved through several different blocks:

Directional (1.4x)

Directional detectors improve detection range by 40% in the direction they face. Most directional detectors can only be mounted on the front of a ship.

*Sensor Panels require a Cruiser or larger military core.

All directional detectors have a 90 degree field of view.

Advanced Directional (2.0x)

Advanced detectors double detection range in the direction they face. Advanced detectors can only be used on Picket or Corvette cores, and must be mounted on the front of a ship.

All advanced detectors have a 15 degree field of view.

Active detection

Two options exist for Active detection of other ships or stations: the Lidar and the Radar.

Lidar

In addition to providing baseline Optical detection and increasing weapon lock range to 24km, the Lidar also has a Ping Mode which can be toggled via the toolbar. When Ping Mode is active, you can select any signal you are currently detecting, and ping it.

When you ping a signal source, your Lidar bounces a high-power Optical laser off it. If you're within your Lidar's maximum range, you'll receive a Strong or Detailed return signal, identifying the faction and potentially ship class of the target.

However, pinging also provided a detailed signal to the target, giving away your location and identity.

When you are pinged by a hostile ship, you will receive a HUD warning and audio alert, and the glow of the Lidar beam will be visible on your ship's hull.

Upgrading the Optical detectors on a ship increases the functional range of its Lidar.

Lidars require line of sight to operate, and larger ships will benefit from having multiple Lidars for increased coverage. Multiple Lidars can be controlled as a group, and the one with the greatest visibility will be used for the ping.

Radar

Radar blocks produce an intense Radio signal in all directions, which can bounce off nearby ships or stations to produce reflected signals.

The further away from the radar, or the smaller the detected grid, the weaker the reflected signal will be.

Each Radar has an Effective Range. This is the distance at which a medium-sized ship (i.e., an average Frigate) will reflect a detectable signal. Larger ships can be detected from further away, while smaller ships must be closer.

Due to the strength of signal they emit, a ship using a Radar can be detected from a significant distance. An active radar can be detected as a Strong signal at 2x its effective range, and a Weak signal at 4x.

When you detect a nearby hostile radar signal, you receive a HUD warning and an audio alert. Any signal emitting radar will display radiating circles around it - the stronger the signal, the more rings. Within detection range, the rings will turn red.

There are two Radar blocks available, with different stats and constraints:

Upgrading the Radio detectors on a ship increases the functional range of its Radar. A Lidar is also useful for further identifying detected weak signals.

Signal relaying

If you are within antenna broadcast range of any nearby allies, any signals either of you detect will be relayed to each other. Signals that have been relayed from another ship are marked by a small icon in the corner.

Intercepting

While the Flip and Burn HUD is active, detected signals can be selected via right-click to lock them as a navigation target. Flip and Burn will provide flight guidance to help guide you towards an intercept with the signal source.