Editing EM Sensor

{{bothversions}}
EM sensors are [[Player Designed Systems|player-designed components]] which are used to detect electromagnetic emissions from other [[races]]. Just like [[Thermal Sensors|thermal sensors]] and [[Deep Space Tracking Station]]s, they are passive sensors, which do not give away your position to enemies. 

EM sensors can be of size 0.1 [[HS]] up to 50 HS. Sensors of size 1 HS or less are [[commercial components]], and larger sensors are [[military components]]. In [[VB6]], all ships have a size-1 sensor of each type installed automatically, making small sensors largely irrelevant, but in [[CSharp|C#]], there are no equivalent automatic sensors. 

In C#, [[ELINT Modules]] also function as EM sensors, with sensitivity equal to their listed rating. See that article for details. 

==Electromagnetic Emissions==
Electromagnetic emissions are created from three sources - [[active sensor]]s, [[colony|colonies]], and [[shields]]. 

An active sensor that is turned off emits no EM signal. An active sensor that is turned on emits an EM signal of strength equal to:
  Strength = Size * Resolution * Grav Pulse Strength

A colony emits an EM signal whose strength is based on the population of the colony and development level of the colony (formula {{unsure}}). You can see the emissions of your own colonies on the Economics screen ({{key|F2}}), Summary tab, below installations in the middle column. 

A shield emits an EM signal of strength equal to:
  Strength = Shield strength * 30

Each source is independent - if a [[fleet]] has a dozen active sensors that are each emitting a 500-strength signal, that is no easier to detect than a single 500-strength signal would be. 

==Detection Mechanics==
An EM sensor's sensitivity is based on its size and your technology level. 
  Sensitivity = Size * EM Sensor Sensitivity tech

The detection range this allows against a signal of any given strength will vary by game [[version]]. 

In [[CSharp|C#]]: 
  Range = sqrt(Sensitivity * Signature strength) * 250,000 km

In [[VB6]]: 
  Range = Sensitivity * Signature strength * 1,000 km

See [https://aurora2.pentarch.org/index.php?topic=8495.msg103085#msg103085 this Steve post] for details. 

When you detect a signature, you can tell its strength and location, but nothing else. It cannot be used for firing [[beam weapon]]s. You can use it to set a waypoint and fire [[missiles]], but those missiles will not hit unless they have their own seekers. 

==Usage==
EM sensors excel at finding active sensors. Spotting your opponents actives can give you valuable information about probable weapon ranges. However active sensors can only be detected if they are turned on, so exclusively relying on EM sensors for passives can lead to a fleet being able to sneak up and only turn on their actives with the first volley. 

Populations have relatively large EM signatures, making EM sensors useful for spotting colonies. You can view the passive sensor detection radius of your ships and installations in the System Map's view by adjusting the Sensors tab values. 

==Statistics==
The cost of a sensor is equal to its sensitivity, multiplied by a factor based on the Electronic Hardening value. In C# the cost is 100% [[Uridium]], and in VB6, it's 75% Uridium and 25% [[Duranium]]. 

A sensor of size 1 [[HS]] or greater has 1 [[HTK]], and a sensor of size smaller than 1 has 0 HTK. The crew need is size*2, rounded normally. 

===EM Sensor Sensitivity===
{| border="1" class="wikitable" style="text-align: center;"
|+ Base Sensitivity
! Sensitivity !! 5 !! 6 !! 8 !! 11 !! 14 !! 18 !! 24 !! 32 !! 40 !! 50!! 60 !! 75
|-
! RP cost
|1,000||2,000||4,000||8,000||15,000||30,000||60,000||120,000||250,000||500,000||1,000,000||2,000,000
|}

===Electronic Hardening===
Electronic Hardening is used to resist the effects of [[High-Powered Microwave]] weapons. The Electronic Hardening technologies differ between versions. 
{| border="1" class="wikitable" style="text-align: center;"
|+ Electronic Hardening (C#)
! Hardening !! 0 !! 1 !! 2 !! 3 !! 4 !! 5 !! 6
|-
! Chance of Destruction (%)
| 100 || 70 || 50 || 30 || 20 || 10 || 5
|-
! RP cost
|Free||2,500||5,000||10,000||20,000||40,000||80,000
|-
! Sensor cost
|Free||+15%||+25%||+35%||+50%||+75%||+100%
|}

{| border="1" class="wikitable" style="text-align: center;"
|+ Electronic Hardening (VB6)
! Hardening !! 0 !! 1 !! 2 !! 3 !! 4 !! 5 !! 6 !! 7 !! 8 
|-
! Chance of Destruction (%)
| 100 || 70 || 50 || 40 || 30 || 25 || 20 || 15 || 10
|-
! RP cost
|1,000||2,500||5,000||10,000||20,000||40,000||75,000||150,000||300,000
|}

{{Components}}
[[Category:Components]]