(Answered) Guardian ECM vs Streaks, Long Range Missiles, and Sensors

[DocBach]

I've already asked this in the "Ask The Writers" section, but unfortunately the people who I was trying to clarify the rules for don't believe Paul's credentials as site manager qualify him to answer the question, so hopefully asking it here in the official rules clarification area will appease them once and for all.

I understand that MechWarrior Online is not a canon extension of the Battletech line, but there has been a lot of controversy revolving around the implementation of Guardian ECM. In MechWarrior, ECM prevents a 'Mech's sensors from detecting enemies outside of 200 meters, making it impossible to fire LRM's or Streak missiles as you have to target with sensors to achieve locks. Reading several descriptions from various readouts and the such makes me believe that ECM isn't suppose to completely deny sensors the ability to lock or track a target, more or less it prevents the identification of the target, supported by the following excerpts:

"The Guardian ECM Suite is a broad-spectrum jamming and electronic countermeasure device, designed to reduce the efficiency of enemy long range scanning and surveillance equipment. The Guardian interferes with sensor readings, preventing identification at ranges of more than 180 meters. Closer than that, 'Mech pilots usually rely on their own vision in case their sensors cannot overide the Guardian's jamming." Technical Readout 2750, page 10

This description supports the idea that Guardian just sort of scrambles the identity of a target when outside of the 180 meter operating radius, ie hiding chassis type from sensors is somewhat supported by the Sensor Scanning rules in Tactical Operations (pg 219-220) in which ECM can prevent a player from gaining information like the above or damage or weapon loadouts.

Page 224 has a rule that states, "to be affected, the spotting unit must be in the normal operating radius of the ECM... LOS does not affect this radius."

Does this mean to have ECM interfere with sensor spotting the spotting unit has to be within the 180 meter ECM bubble projected by the Guardian, or does any line of sight crossing in to it get countered by the ECM, like how ECM defeats attacks augmented by Artemis that cross through the bubble?

More or less, I'm trying to get an answer if ECM could be construed to be a counter missile system and defeat a targeting and tracking systems ability to lock on and employ guided systems like Streak Missiles / LRM's in an ECM environment. Thanks.

[Paul]

I've already asked this in the "Ask The Writers" section, but unfortunately the people who I was trying to clarify the rules for don't believe Paul's credentials as site manager qualify him to answer the question, so hopefully asking it here in the official rules clarification area will appease them once and for all.

Well, it is true that only answers in these forums should be seen as 'official', yes. So it's a good follow up.
But beyond just working on the site side, I'm also a writer, and the rules admin for ATOW questions.
Still, that doesn't make me the rules admin on TO questions.

For curiosity's sake, care to drop a link to the thread in question? Feel free to PM if you'd prefer.

Paul

[DocBach]

https://mwomercs.com/forums/topic/99038-my-conclusion-on-ecm/page__st__40

Link to the thread, one of about two-gazillion on the effects of ECM in MechWarrior: Online.

[Paul]

Thanks!
My fragile ego is heinously wounded, but I can assure you your question will get an official response in the near future.
And yes, it is possible that response differs from mine, I do err. So, let's find out! =)

[Paul]

The answer as arrived at by the rules committee:

To be clear, TRO2750 is not directly relevant to the modern game rules in anything but a historical sense, and more broadly fluff descriptions are not part of how the game rules are evaluated.  The primary Guardian ECM rules are on Total Warfare pages 134-135 and specifically mention they affect weapons tracing LOS through the ECM area of effect.  Please note that while we're using the term "Guardian ECM", the rules apply equally to Clan ECM suites or other systems (such as the Capellans' late Succession Wars Electronic Warfare) that provides effects equivalent to IS Guardian ECM.  Angel ECM is on Tactical Operations page 279.

Broadly speaking, ECM is primarily a defense against advanced systems, not baseline capabilities like targeting for standard SRMs and LRMs absent any kind of enhancement.  Those types of standard missiles are not affected in the slightest by ECM suites, either Guardian or Angel, unless you use the optional ghost targets rules (which affect all weapons the same way).

Guardian ECM doesn't affect Streak systems of any type (SRMs, LRMs, or improved ATMs).  Angel ECM does block Streak's bypass of the cluster hits table if it's operating in standard mode.  The rules for Angel on specifically note the Streak effect is blocked if fired into or through the ECM bubble, consistent with the basic Guardian rules.

As you noticed about Artemis IV (and Artemis V against Angel ECM), hostile ECM merely in the LOS causes the missiles to operate as standard missiles.

Of note:
Narc-seeking missiles fall back to standard behaviors for that missile type if the target is within an ECM bubble, but are not affected by a bubble that's merely in the LOS to the target.