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ECM Number Crunching

What is the purpose of ECM

The purpose of ECM is to “jam” someone, which means to prohibit the targeted ship to lock anything else in space (ships, cans, whatever) or to break the current locks. Each ECM module has a cycle time (20 s) and has a certain probability of landing a “hit” on each cycle. That probability is based on the ratio between your own 'ECM strength' (JS) and the 'sensor strength of your target' (SS).

ECM probability is influenced by

  • Signal Dispersion (5% ECM strength per level)
  • Long Distance Jamming (10% Optimal Range per level)
  • Frequency Modulation (10% Falloff Range per level)
  • Electronic Warfare (5% reduction of cap usage per level)
  • Ship bonuses (e.g. Recon ships)


There are two basic types of jammers: Racial and Multispectral. Racial jammers are heavily biased to a specific race and nearly useless against the other three. Multi jammers are not as strong as the racials against a single race but equal in strength against all four races.

  • Caldari (dark blue) Gravimetric
  • Minmatar (red) Ladar
  • Gallente (green) Magnometric
  • Amarr (yellow) Radar


  • LG Centurion Set (bonus to optimal range)
  • Slot 9 EW-90X capacitor useage


  • Particle Dispersion Projector (Bonus on Optimal Range)
  • Particle Dispersion Augmentor (Bonus on ECM strength)

Low slots:

  • Signal Distortion Amplifier (Bonus to Range and ECM strength)
  • Backup Arrays (increases the sensor strength of the ship, ECCM)

Med slots:

  • ECM Bursts (Lockbreaker, this is not a Jammer!)
  • ECCM (Electronic counter counter measure, to increase the sensor strength of your own ship)

Conclusion: Racial Jammer => more ECM strength and more range



  • 15% Bonus on jammer strength
  • 10% Bonus on capacitor usage


  • 15% Bonus on jammer strength
  • 10% Bonus on optimal range and falloff


  • 20% Bonus on jammer strength
  • 10% Bonus on capacitor usage
  • 10% Bonus to optimal range
  • 5% Bonus to capacitor usage


  • 5% Bonus on Heavy/Heavy Assault missile rate of fire
  • 10% Bonus on capacitor usage
  • 30% Bonus on ECM strength
  • 10% Bonus on Heavy/Heavy Aussault missile velocity


  • 30% Bonus on jammer strength
  • 10% Bonus on capacitor usage
  • 5% Bonus on medium hybrid damage
  • 96-100% Bonus on Liquid Ozone consumption
  • 50% Bonus on cyno duration


  • 15% Bonus on jammer strength
  • 20% Bonus on optimal Range and falloff
  • 20% Bonus on ECM burst range


  • 30% Bonus on jammer strength
  • 125% Bonus on ships velocity while cloaked

Let’s do some Math - Probabilities

Little example - Coin toss

What’s the probability to get heads?

  • Two possible outcomes (heads or tails)
  • Single independent try
  • Result unit is percent
    • E[%]=(1/2)*100=50%

What is the probability of one minmatar racial jammer (JS=3.6) to hit a Hurricane (SS=16)?

  • Minmatar Racial on Hurricane
    • E[%]=(JS/SS)*100=(3.6/16)*100=22.5%
  • Minmatar Racial on Drake
    • E[%]=(1.2/19)*100=6.3%
  • Multi on Hurricane
    • E[%]=(2.4/16)*100=15%

Not the best results even with a racial jammer we only get a probability of 22.5% which is almost only one out of five trys would be a hit. But there are some enhancements .-)

Probabilities + Skills


  • All jamming related skill at lvl 4
  • Recon skill at lvl 5
  • Used ship is a Falcon

This leads to an overall JS with racial jammers of 14.27. With the new much higher JS strength what is the probability to hit a Hurricane.

  • Minmatar Racial on Hurricane
    • E[\%]=(JS/SS)*100=(14.27/16)*100=89.19%
  • Minmatar Racial on Drake
    • E[\%]=(4.76/19)*100=25.05%
  • Multi on Hurricane
    • E[\%]=(9.51/16)*100=59.43%

This shows an incredible increase to successfully jam a target with a 'SINGLE' racial jammer. Even the other three races have a reasonable chance to succeed.

Multiple Jammer on a single target

Two racial Jammers

Same Scenario:

  • All jamming related skill at lvl 4
  • Recon skill at lvl 5
  • Used ship is a Falcon

What is the probabilty to hit a target with two red racial jammers (JS=14.27). The target is a ECCM fit Scimitar (SS=33). The Formula for multiple jammers is defined with:

  • n …number of ECM modules of the same strength/type
  • JS …jammer strength with skills and ship bonus
  • SS …sensor strength of your target (with modules and skills)

E[\%]=(1 - (1 - JS/SS)^n)*100

This leads to the following numbers:

  • Two Minmatar Racial on Scimitar with ECCM
    • E[\%]=(1 - (1 - JS/SS)^n)*100=(1-(1-14.27/33)^2)*100=67.8%
  • Two Minmatar Racial on Basilisk with ECCM
    • E[\%]=(1-(1-4.76/43)^2)*100=20.91%
  • Two Multi on Scimitar with ECCM
    • E[\%]=(1-(1-9.51/33)^2)*100=49.33%

The effect of using racial jammers compared to multis is in this case 18.47% greater.

Rainbow fit

Same Scenario:

  • All jamming related skill at lvl 4
  • Recon skill at lvl 5
  • Used ship is a Falcon

Using a full rainbow rack, what is the cumulative probability of a successful jam cycle? The ship used is a Falcon against a Raven (SS=22). The Falcon provides us a JS with the Caldari jammer of 14.27 with the other three only 4.76. The formula changes slightly to a multiplication of each and every jammer module used:

  • E[\%]=1))*100
  • E[\%]=(1 - 2))*100 = 83.09%

If your Falcon is for example fit with 4 Caldari jammers (JS=14.27) we would hit the target with a probability of:

  • E[\%]=(1-(1-14.27/22)^4)*100=98.47%

If your Falcon is for example fit with 4 Multis (JS=9.51) we would hit the target with a probability of:

  • E[\%]=(1-(1-9.51/22)^4)*100=89.61%

ECM Drones

Some number crunching for drones:

  • Hornet EC-300 (light) -> JS=1
  • Vespa EC-600 (medium) -> JS=1.5
  • Wasp EC-900 (heavy) -> JS=2

The probability to hit a Drake (SS=19) with five drone of the same type.

  • 5 EC-300 Hornets
    • E[\%]=(1 - (1 - 1/19)^5) * 100=23.69%
  • 5 EC-600 Vespas
    • E[\%]=(1 - (1 - 1.5/19)^5) * 100=33.71%
  • 5 EC-900 Wasps
    • E[\%]=(1 - (1 - 2/19)^5) * 100=42.66%

Unfortunately there is no skill to increase the ECM strength of drones.


Two diffenet types are available to increase your own sensor strength and one to increase your targets sensor strength (Projected ECCM Modules). For example: Med-Slot - eg. Gravi Low-Slot - type can be replaced with Grav/Ladar/Magno/Radar

Hints to use ECM

Fighting in Falloff

Try not to fight in falloff if at all possible.

  • ECM module with 61km optimal and 50km falloff
  • 14 JS in optimal drops to 7 at 111km (61+50km)
  • e.g. Raven (SS=22) with one racial
    • E[\%]=(14/22)*100=63.63%
    • E[\%]=(7/22)*100=31.81%


  • The backgroud of the image shown for target locks indicates the jammer you should use.
  • Always flight aligned to warp off if you get hit.
  • If you can, because it is a hot spot, create tactical bookmarks with optimals for jamming and on grid warp points.
  • turn auto-repeat off for the jamming modules

  • do not jamm the primary target unless your are told to (jammed targets are not shooting == de-aggressed)
  • find your targets, e.g. by name (in big fleets) or priorities them by ship type eg. Jammer, logies, dps
  • Capitals (Supers and Titans can’t be jammed, same for Triage/Siege):
    • Chimera: sensor strength 80, with ECCM 157
    • Archon: sensor strength 72, with ECCM 141
    • Nidhoggur: sensor strength 68, with ECCM 133
    • Thanatos: sensor strength 76, with ECCM 149

PDF Version - ecm.pdf

1 - ((1 - JS/SS)*(1 - JS/SS)*(1 - JS/SS)*(1 - JS/SS
1 - 14.27/22)*(1 - 4.76/22)*(1 - 4.76/22)*(1 - 4.76/22
eve/pvp/electronic_warfare/ecm/ecm_number_crunching.txt · Last modified: 2017/02/12 16:25 by conscript