Sigismund, on 10 February 2013 - 06:13 PM, said:
ECM wouldn't be a fiery subject if they just stuck to the tabletop rules for the ECM Guardian Suite. Forgive me if these rules were already posted but the Sarna entry is a little ambiguous about ECM's exact properties.
"A Guardian system nullifies the effects of any enemy BAP, Artemis, Narc or C3 when any of these systems are within 6 hexes (180m) of a Guardian equipped unit. The Guardian ECM suite does not affect other scanning and targeting devices, such as TAG and Clan targeting computers... It also affects any enemy system whose path passes within (180m) of the Guardian. e.g. if the LOS to a narc or between two C3 linked units passes within (180m) the line of communication is broken."
Those are the exact rules for the ECM. It's only original function was AS a counter to BAP, Artemis and C3 i.e. high level information sharing between allies which comes standard in the video games. It doesn't affect weapon or missile lockon nor does it affect your ability to target enemies and target information. It only hampers your ability to give and recieve that information to your allies.
A better solution to making BAP counter ECM is to stop ECM from doing stuff it was never intended to do.
Actually, what's on Sarna isn't the
exact wording, but it's fairly enough.
"An ECM suite has an effect radius of six hexes that creates a “bubble” around the carrying unit.
The ECM’s disruptive abilities affect all enemy units inside this bubble, as well as any line of sight traced through the bubble. It has no effect on units friendly to the unit carrying the ECM.
In the ECM diagram, the ’Mech in Hex A on the Open Terrain #1 map is equipped with an ECM suite, which has an effect radius of six hexes (shown as the shaded area). The suite affects any enemy unit in this area or any enemy LOS traced through it.
The ’Mech in Hex B is affected because it falls inside the effect radius.
A shot from Hex C to Hex D would also be affected because LOS passes through the radius.
A shot from Hex C to Hex E would not be affected because LOS does not pass through the radius.
Within its effect radius, an ECM suite has the following effects on the following systems. The ECM suite does not affect other scanning and targeting devices, such as TAG and targeting computers."
(from page 134 of the core BattleTech rulebook,
Total Warfare)
The "following effects" go on to describe how ECM Suites (that is, all of them - Guardian, its unnamed Clan counterpart, and Angel) completely nullify the effects of Active Probes (more specifically, Beagle), Artemis IV, Narc, and both C3 and C3i.
Additionally, the example describing the shot from Hex C to Hex D is of particular note, since the accompanying chart in the book shows that both Hex C and Hex D are outside of the ECM bubble (that is, more than 6 hexes away from the ECM unit in Hex A), but the shot is still affected because it must pass into the bubble (and back out again) to get from C to D and "the ECM’s disruptive abilities affect all enemy units inside this bubble,
as well as any line of sight traced through the bubble"; this explicitly shows that ECM can affect units outside of the 180 meter (6 hex) bubble, as long as their action (a shot... or a sensor probe) has a LOS that in any way comes into contact with the bubble.
Also, to also be considered are the advanced combat and equipment rules from another of the core BattleTech rulebooks,
Tactical Operations.
"The ranges of various electronic sensor systems appear in the Sensor Range Table, p. 222.
To make a Sensor Check, the player rolls 2D6. A result of 7 or 8 means the sensor detects any unit within its short range. A result of 5 or 6 means the sensor detects units out to its medium range. A result of 2 to 4 means the sensor detects units out to its long range.
A roll of 9 to 12 means the sensor failed to detect any units."
(from the "double-blind rules" in
Tactical Operations, pg. 222)
"Just as special sensors can make spotting enemy units easier, special ECM and stealth systems can make units harder to detect.
As a general rule, ECM/stealth systems mask a unit’s nature and precise location from enemy sensors, but the systems’ powerful jamming devices make it clear to the enemy that something is out there.
In the double-blind game, all ECM and stealth systems modify the die roll results of spotting units attempting to detect an enemy unit equipped with such an ECM system. Because different ECM/stealth systems have different effects against different probes and sensors, the modifiers vary depending on the spotting unit’s probe/sensor and the enemy unit’s ECM system. These modifiers appear in the ECM/Stealth Modifier Table.
Once the sensor detection dice roll has been made (including adding any bonus modifiers from the controlling player’s side), the player consults the ECM/Stealth Modifier Table and adds the applicable modifier to the roll result."
(from the "ECM/Stealth Systems" section of the double-blind rules, pg. 224 of TacOps)
The ECM/Stealth Modifier table (on page 223 of TacOps) indicates that Guardian ECM adds five (+5) to the result of a sensor roll made using standard 'Mech sensors, and adds four (+4) to a sensor roll made against a Beagle Active Probe.
(For comparison, the same table shows that the more-powerful Angel ECM levels even greater penalties: +7 against standard sensors and +6 against Beagle.)
On top of that, a result of 9 or more means that "
the sensor failed to detect any units".
So, against a 'Mech with standard sensors, an ECM carrier would have to worry about detection if the roll comes up as less than four (since a roll of 4 plus ECM's modifier of +5 equals 9, the "failure to detect" condition); in TT terms, only a roll of 2 or 3 would matter.
In terms of 2D6 probabilities, the combined likelihood of a 2 or 3 is on the order of ~8-9%... meaning that there is a 90+% chance that a Guardian ECM system would prevent standard 'Mech sensors from detecting the ECM-equipped unit (or any other unit under the ECM bubble), even if the target is actually outside of the 180 meter radius of the ECM bubble.
In terms of real-time, we could also say that the failure-to-detect indicates that the target's sensors cannot "see" the ECM carrier.
And if the ECM carrier cannot be seen by the target's sensors, the target's fire control system (which relys on the information from said sensors) can't establish a weapons lock (since, obviously, it can't lock onto what it can't see).
And if the target's fore control system can't get a weapons lock, weapons that won't fire unless and until said lock is achieved (that is, Streak missiles) simply cannot be fired while other weapons that use the locking capability for certain tasks (that is, LRMs' ability to track and home-in on an opponent) lose those capabilities.
So, from a "BT rules standpoint", MWO's current Guardian/Streak interaction is (IMO) arguably justifiable.
The analogous logic behind how (beyond "because the BT rules say so") Angel does its thing (making Streaks dumbfire), on the other hand, is something I've yet to figure out...
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