How much probe strength do I need? – Combat Probing Edition

Scanning Week continues at Pilgrim in Exile.

In my last post, I talked about determining how much probing strength you need to scan down cosmic signatures. In this post, I will discuss the probe scan strength needed to scan down ships and structures. There are 2 big differences. The first is that combat probes have half the base probe strength of core probes due to the fact that they can only “zoom in” to 0.5AU’s instead of 0.25AU’s. The second difference is in the signal strength of your target is calculated.

The casual, unofficial formula I use is:

Probe Strength * AU modifier * Placement modifier * Signal Strength = Scan Result


Probe Strength is your Base Sensor Strength

AU modifier is 100% at Base Scan Range (ie 100% at 0.5AU’s ; 50% at 1AU; etc.)

Placement modifier is 100% when all of your probes are perfectly centered on the signature

Signal Strength = Target Signature Radius / Target Sensor Strength / 100

Scan Result is the result returned by your scanning. 100% is needed for warp-in.

For exploration probing, the signal strength was determined by the type/band of cosmic signature. For ships and structures, it is a little different. It is the Signature Radius divided by the Sensor Strength (divided by 100 to get percent). How do you determine this? Well, the unmodified attributes can be found in the info about the ship or structure. For example:


For the Mammoth, look under “Targeting” and see that it has 8 points of Sensor Strength and a Signature Radius of 180. It’s Signal Strength is 22.5%. Pretty easy to scan down.

Another example:


This Magnate has 10 points of Sensor Strength and a Signature Radius of 39. It’s Signal Strength is 3.9%. A bit harder to scan down. So how much Probe Strength would you need to scan it down? Well, if we assume 85% placement accuracy, you would need 30.2 (100%/3.9%/85% = 30.2)

Structures also have these attributes. Here is a standard mobile depot:


With a Signature Radius of 500 and 50 points of Sensor Strength, it has a Signal Strength of 10%.

Now, these are the stock attributes. For ships, these attributes can be modified by rigs and modules as well as player skills. For signature radius, there are a number of things that increase signature radius including Shield Extenders, Shield Rigs, and the use of a MWD. There are also a number of things that increase Sensor Strength including ECCM modules and Sensor Compensation skills. It is for this reason that you can’t know for sure how much Probe Strength you will need. For combat probing, more is always better!

The maximum Combat Probe strength I could get with all implants, rigs, modules, and skills was 100. This means a maxed out prober could scan down a Signal Strength of 1.053% (at 95% placement accuracy). There used to be “unprobable” Tengu’s, that could get close to that, but I don’t think they still can. Could be wrong though.

Suppose you want to scan down an Archon carrier without them seeing your combat probes. You would need to adjust your probe layout (so that none are centered on the target) and you would also need to be able to place the probes at 16AU’s. Can you do it? At 16 AU’s, the AU modifier is 3.125%. A stock Archon has a Signature Radius of 2920 with a Sensor Strength of 72. That gives it a very fat Signal Strength of 40.5%. If you can use d-scan well, you could probably get a placement accuracy of 85%. So with 100%/90%/40.5%/3.125 = 93. Doable, but challenging. If you can get a placement accuracy of 90%, you can do it with 89 probe strength.

At the other end of the scale, the new “Yurt” variation of the mobile depot has a Signature Radius of 500 and a Sensor Strength of 400 giving it a Signal Strength of 1.25%. At 85% placement accuracy, you need a probe strength of 94 to scan it down.


One thought on “How much probe strength do I need? – Combat Probing Edition

  1. Semion

    Please explain in detail. For example, if my ship has a signature (119) and sensor strength (157), how to calculate the Scan Result for (Probe Strength = 93.1, AU modifier 100%, Placement modifier = 95%). Does this formula takes into account the number of running probes, or it does not matter?

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