SO I'm in a corp with a bunch of miners, and we've just been war decced by a one-man corp. Most of our skills are focused on the industry and mining side of things, with not a lot of attention paid to the combat side. Since we're all a bunch of rather low-sp players, my first thought was to use ECM to give us an advantage, but I'm having a little trouble understanding how it works. I get that it's based on chance, based on your ECM strength and the sensor strength of your target, but does it stack? Meaning, do our chances of locking a guy out improve if we can get multiple people to jam a target with multiple racial jammers or multispec?
The first important point to think about when bringing ECM is how you will prevent the enemy from killing your ECM. ECM ships have low tank and can take out multiple enemy ships, they are almost always the first ships to be called primary. You have two options to keep your ECM alive:
The chance to jam with one jammer is jam strength/sensor strength, so if your jam strength is higher than the enemy sensor strength you will effectively perma-jam the enemy. If it is lower, you will only have a certain percentage chance to jam. Examples:
If you have a below-100% chance to jam, you can use multiple modules (on the same ship or on other ECM ships) to increase the chance to jam. The chance to jam follows the following formula for multiple jammers:
So if you try to jam the hurricane with 2 jammers you get a 75% chance of at least one jam succeding, and 88% chance for 3 jammers.
You can also overheat your jammers to increase the chance to jam for a short time if you have the thermodynamics skill. You should also pretty much always use racial jammers, they are far better than multispectrals. You need to either guess which ships the enemy brings or get some intel before the fight to chose the appropriate jammers.
Mad Scientist is providing you with some out of date information
ECM modules do NOT stack. The chance of a jam succeeding on a particular cycle is independent of any other ECM modules you have. There are some modules that will increase the strength of your ECM modules, but the modules that actually DO the jamming are independent of each other. So although each module will have the same chance to jam as the next one based on your skills, the more modules you have, the more chances you have.
Also, although I don't know the exact formula, I do know that you are never GUARANTEED to jam someone, regardless of yours or their respective sensor strengths. Sensor strengths will affect your chances of jamming, but it's no longer based solely on ship sensor strengths. It used to be, so it used to be the way that Mad Scientist states, but it's no longer that way. You can have a jam strength of 10 against a ship with a jam strength of 5, and it is possible for you to still miss a jam cycle. You will most likely perma-jam them, but it IS possible to miss a cycle.
Racial jammers are best if you know what you're going up against, but don't hesitate to activate the module for the wrong race anyway. Although the sensor strength is lower, there is still a chance to jam them. I have jammed several ships using off race modules. You certainly have a lower chance of succeeding, but it's still very do-able. I have a rainbow set up on my Griffin (one of each race), and my Falcon has 2 of each, except Amarr, which only has one (only 7 mids on the Falcon).
As to the tank of an ECM ship - it's tank is ECM. If you jam the hostile, your tank is working. If you can't jam the hostile, your tank is not working. Simple as that.
The simplest answer is that ECM from multiple pilots does not stack.
As to the overall problem, it's regularly stated that a lot of poor quality pilots often have a chance against a single skilled pilot, but that is really another question you should ask and a rather broad one at that.