How to Use Site Activity Monitor in Phasmophobia

Learn about a ghost, including EMF 5 evidence, and details on how to use the site activity tracker.

In Phasmophobia, knowing about a ghost is important in determining your strategy and progressing. In this guide, we explained how to use the site activity monitor and how to get information about ghosts thanks to it.

Site Activity Monitor

This guide details how to use the Site Activity Monitor in the truck (referred to as SAM from now on). This is SAM:

How to use the Site Activity Monitor

The main reason I’m making this guide is because I see A LOT of incorrect information about it posted in the forums and most people don’t seem to know how it works. There’s no in game explanation for it either. The higher difficulties, Nightmare and Insanity, disable the monitor, so most experienced players don’t pay much attention to it. However it is a powerful tool on Professional difficulty and below.

You can use SAM to:

  • Imply EMF 5 evidence is likely without other information
  • Imply EMF 5 evidence is unlikely
  • Determine EMF 5 conclusively if you have other information
  • Spot the Twins ability. Potentially can be 100% proof of Twins on it’s own, even ruling out Mimic.
  • Spot Poltergeist ability that could be Poltergeist or Mimic.
  • Know when the ghost is hunting and when it is not.
  • Gauge how active the ghost is based on how frequently the graph is changing. Very passive ghosts can require different strategies, such as ensuring you preserve your sanity because getting evidence will take longer.

How SAM works

SAM is a running total of the sum all the EMF readings in the investigation area (aka house). Every time the graph increases, that means the ghost did something that caused an EMF reading. The reading will last a certain period of time, then go back down. Each change (referred to as a spike) is the EMF reading that occurred with a random value between 0 and 2 subtracted from it.

A list of all things that can cause SAM spikes:

  • Normal interactions – EMF 2 or 3 depending on the interaction. Causes spikes between 0 (invisible) to 3. These are the most common thing you’ll see on the graph.
  • EMF 5 interaction. Each normal interaction has a 25% chance of being EMF 5 instead of 2 or 3. This causes spikes between 3 to 5.
  • Ghost event. EMF 4 reading + additional for any extra activity. Causes spike between 2 to 10. Can only occur if someone is in the house.
  • Hunt. Hunts will always max out SAM to 10 and will keep it there until the end of the hunt. Can only occur if someone is in the house. More on this in a later section.
  • Poltergeist throw ability. EMF can be anything from 2 to 10 depending on items thrown. Causes spike anywhere between 0 to 10. More on this in a later section.
  • Twins ability. This is a double interaction and has a unique pattern that makes it look different from anything else. More on this in a later section.
  • Some ghosts have abilities that cause an EMF 2 or 3 reading, like the Jinn when it uses it’s ability to sap sanity on the breaker or a Yurei when it slams a door. These special abilities can also cause EMF 5 if the ghost has it as evidence, same as a normal interaction. These are indistinguishable from normal interactions on SAM.
  • (WIP: Needs in game confirmation) The use of some cursed possessions can cause EMF 2 or 3 readings, and sometimes even double interactions that appear like the Twins ability (WIP: claim comes from wiki – I need to confirm and find which item – it isn’t the voodoo doll). This is a very niche situation and I don’t have much knowledge of the specific mechanics of cursed items. I tend to avoid using them because I rarely feel the sanity cost is worth the benefit they give. So cursed items will be ignored for the rest of this guide.

(WIP: Typical Screenshot with further explanation)

(WIP: High activity screenshot)

(WIP: Low activity screenshot)


As mentioned before, hunts will always send SAM to 10 as soon as the hunt starts and will hold it there until the end of the hunt. 10 doesn’t necessarily mean the ghost is hunting, events or even a lot of normal interactions can get SAM to 10. But if the activity is not 10, the ghost is not hunting. So if a hunt starts and the graph is 10, when the graph drops below 10 the hunt has ended. You can often see if someone has been killed on lower difficulties if a hunt ends prematurely.

I consider it good practice to warn your teammates if you see SAM suddenly hit 10. It may only be an event, but warning people early can save lives. I’ve died plenty of times because I was carrying things to the ghost room and got caught because I had no idea the ghost was hunting. It’s also good to tell people when a hunt has ended so they don’t waste time hiding when it’s not hunting.

(WIP: Screenshots)

Determining EMF 5 from SAM

This is what most people will be here for. Despite many claims to the contrary, and with some extra information, SAM can be a reliable way to determine EMF 5. What you are looking for are spikes of strength 4 or 5. If you see such as spike it can only be the following things:

  • Hunt. If the spike didn’t hit 10, or nobody was in the house, or the front door didn’t lock shut, then it wasn’t a hunt.
  • Ghost event. Can be eliminated as a possibility if nobody was in the house or everyone agrees there wasn’t any event.
  • Poltergeist ability. Poltergeist and Mimic can be eliminated with other evidence, such as ruling out UV.
  • Twins ability. It has a unique pattern that can eliminate it (more on that below). Twins has EMF 5 evidence anyway.
  • EMF 5. If you eliminate all the above you have EMF 5 evidence.

Because the graph shows over 60 seconds, you can just check it whenever you go back into the truck. Personally I find this a much easier method to get EMF 5 than using the EMF meter, especially the T1. If you aren’t confident in reading SAM, then you can always double check using the EMF meter, and this will at least give you some direction on what to focus on.

How to use the Site Activity Monitor

EMF 5 can be seen on the right hand side of the graph. There is a drop from strength 5 to 0 at 47 seconds. The spike up at around 16 seconds is a Twins ability.

On the other hand, if you see something like this:

(WIP: insert lots of low level activity screenshot)

This implies that it is unlikely the ghost has EMF 5 evidence. It’s not conclusive, but it’s unlikely that you would have so many interactions without the 25% chance of an EMF 5 interaction occurring. Of course, because EMF 5 can possibly give a spike of 3 on SAM, you need to see a lot of these spikes of 3 or below without any 4 or 5 spikes before you can confidently rule out EMF 5.

Spotting the Twins

Twins ability shows a unique pattern on SAM and is something that once you learn to see it, you can nail the Twins every time. When it does it’s ability, it is a double interaction where the 2nd interaction occurs exactly 1 second after the first. This produces a spike that is over 2 seconds instead of 1. The interactions often give different changes on SAM due to the random nature of the readings, producing a change in gradient over the 2 second spike. But this gradient change doesn’t always occur. One or even both of the interactions can potentially be EMF 5. The Mimic can mimic the Twins ability, but not EMF 5, so if you see an EMF 5 interaction in a Twin spike, it is 100% guaranteed Twins. That is quite powerful given that you could potentially identify Twins from SAM with confidence without ever going inside the house (you do need to unlock the front door).

How to use the Site Activity Monitor

The Twins ability can be seen on the left side at around 16 seconds. You can see that it jumps up from 0 to 1 and then immediately jumps again up to 4. This gives the appearance of a single spike from 0 to 4, but it’s over 2 seconds and the gradient is different over the spike. There are also an EMF 5 drop over on the right hand side at 47 seconds. This isn’t the Twins ability as the change only occurs over 1 second. This graph can only be Twins or a Mimic.

How to use the Site Activity Monitor

The Twins ability can be seen twice on this graph, a big one on the left at 10 seconds and one on the right at 56 seconds. The left one has an EMF 5 reading as the first interaction, where it jumps from 1 to 6, and a smaller interaction jumping from 6 to 8. The EMF 5 is guaranteed because it is part of the Twins ability and thus can’t be from a ghost event. Mimic can’t have EMF, so seeing this graph alone is proof of the Twins.

Poltergeist Ability

Poltergeist ability can be determined from SAM and will often be a very large spike, sometimes to 10, outside of any event or hunt. Spikes of 4 or 5 can be informative, but you need to be able to rule out EMF 5. Spikes of 6 or more can only be the following:

  • Hunt.
  • Ghost Event.
  • Twins ability. It looks different so if you know what you are looking at you can usually rule it out 9 times out of 10. Twins can also be ruled out with evidence.
  • Poltergeist Ability.

So if you see single spike of 6 or more and you can rule out hunt or event, then it’s either a Poltergeist or a Mimic mimicking a Poltergeist. Easiest way to eliminate Mimic is to look for ghost orbs in it’s room. If it’s got orbs, then Mimic. No orbs, no Mimic. Gotta be sure you know it’s ghost room, and it didn’t change, before ruling it out though. Best way to know it’s still it’s room is motion sensors. Applies to any difficulty.

SAM isn’t the best way to confirm a Poltergeist ability though. The best way is to make a pile of throw-able objects (known as a Polterpile) in it’s room and then setup a camera to watch it. If it makes the pile explode everywhere, it’s a Poltergeist (or Mimic). Do watch it with a camera because the sanity damage when it makes it explode will be large. However it’s inconclusive if it doesn’t touch it, because sometimes it takes AGES for it to do the ability. Best if you ensure ALL throw-able objects within it’s reach are in the pile.

(WIP: screenshots)

How is SAM Generally Used?

I use SAM in the following ways:

  • Most often is just checking it whenever I go back to the truck. If I see a likely but not conclusive EMF 5 reading on the graph and I’m playing alone, I may watch it for a while to see if it happens again. If it does, then I know it’s either got EMF 5 evidence, or it’s a Poltergeist or Mimic. If I’m playing with other people, I’ll tell them that the ghost probably has EMF 5 but we need to confirm. If I see a lot of low level activity but no possible EMF 5 spikes, and I see this on a few different occasions, I’ll tentatively cross off EMF 5 evidence.
  • If I’m in the truck for an extended time anyway, such as watching for DOTS or listening to sound sensors, then I’ll also keep an eye on SAM too. If it happens to give me information, then that’s a bonus.
  • If the ghost is constantly hunting, and EMF 5 is one of the evidences that remain, then I will sit and watch SAM instead of going in with an EMF reader. If I can’t get something conclusive in a reasonable time frame, and I think it’s too risky to go back in, then I will guess based on what I saw on SAM.
  • Sometimes I just support my teammates from the truck (aka truck monkey). I only do when I don’t think I’ll add any benefit by being in the house. This is usually in the later part of the investigation when people are hunt testing or waiting for evidence and team sanity is getting low. SAM lets me know when the ghost is hunting, and by passing that information onto teammates I can really help their survivability. Letting them know it has stopped hunting saves them time and sanity if they were hiding in the dark. If I’m being a truck monkey, I’ll also use sound sensors and motion sensors. Sound sensors I spread over the house, as a ghost makes a distinctive sound when it hunts and listening to the speed of its footsteps during a hunt can determine which ghost it is. Motion sensors in the ghost’s room are effective at determining if a ghost is still in it’s room or if it has changed rooms. This is pretty useful as it can be hard for people in the house to know when a room change has occurred and much easier for someone who is watching the truck screens. Room changes are only applicable on Professional difficulty and up, as ghost can’t change rooms in Amateur or Intermediate. Lastly, keeping an eye on the sanity monitor you can tell the rest of the team when critical thresholds are approaching or passed, namely the 50% threshold when most ghosts can begin hunting.
Written by BrendyBear

Leave a Comment

Your email address will not be published. Required fields are marked *