Talk:UFO Detection
Removed sentance suggesting using the graphs to locate UFOs general area being a 'borderline exploit', after all your base could well come with a telephone so governments can call and tell you that their civilians have been reporting UFOs flying over their terrority. It would seem to be a fairly essential way of defending the rest of the world in the first month or two while you get other bases set up to detect more aliens anyway, otherwise your interceptor would have almost nothing to do with your piddling little single radar covering about 5% of the land surface, and missing half the UFOs that wander over that terrority for 10-12 hours anyway (let alone missing anything fast moving 90-95% of the time). Its not like it is something you want to be doing for long anyway, as its fairly fiddly to keep checking the graphs every hour or so for new contacts.
--Sfnhltb 15:01, 26 February 2007 (PST)
Added a load here - the detection rates are based on the values in BASE.DAT and some hex editted trials of game saves that bore out that the values there seemed to be percentages. As this value seems to not get increased by building extra radars, this would seem to indicate the suggestions that more than one of each type are useless, but the combo of 1 short/1 long is valid (until hyperwave of course). The range of short radars was done by testing at what point on the map UFOs could get to without disappearing (factoring in that they almost always disappear only when each 30 minutes is up, so positions between those times dont count as part of the range). This assumes that the point at which you lose contact is based on the same range as you can spot them, but I think this is a reasonable assumption.
Note I tried a few things to try to disprove these hypothesis, such as building 20+ large radars in all 8 bases - no clear increase in detection rate over a dozen or more reloads of the same time period (ran for about a day, just to let the existing UFOs move about, and see if any more were seen compared to a similar amount of runs with just 1 radar). Changing the BASE.DAT detection rates for short/long to 100 each saw an immediate increase in detection rate, so it seems these values are what is used by the geoscape. They reset when you complete a build of any new facility it that base, so you could have 100% radars if you wanted, but only if you dont build anything new (or remember to go back and re-edit any time you complete something). Of course if you are doing that, why not just edit a hyperwave decoder in...
--Sfnhltb 18:55, 26 February 2007 (PST)
We really need to look at the Small and Large radar pages. Simply put, much of the information in-game doesn't agree with game file analysis. In fact, it normally is in direct disagreement with both game files and the Official Strategy Guide (OSG). Here's a table I drew up a long time ago to show the differences. Please note that the detection ranges listed in the OSG are 1/5 that of in-game, so we can back-calculate it's hypothetical range of 480.
| Radar | Det. % | Det. Range | Sweep Rate |
|---|---|---|---|
| Small (in-game) | 5% | 300nm | 10 |
| Small (game file) | 10% | 1500nm (OSG) | 30 |
| Large (in-game) | 5% | 450nm | 10 |
| Large (game file) | 20% | 2250nm (OSG) | 30 |
| Hyperwave (in game) | 100% | ? (480) | DNA |
| Hyperwave (game file) | 100% | 2400nm (OSG) | 30 |
--Zombie 19:35, 26 February 2007 (PST)
- I think they now match up mostly to what you have above, with a couple of differences being as they have been calculated experimentally (and fairly roughly) they show some level of deviation, and also there definitely seems to be an extended tracking belt from my tests that is not covered in the table, although its exact size is open to question a little, but it certainly seems to be larger that 1500 for Small Radars.
--Sfnhltb 21:43, 26 February 2007 (PST)
I might have missed some of the discussion, but do UFOs leaving the tracking zone disappear and reappear on the half hour? I've always had the impression that they just dropped off and reappeared instantly the moment they cross into or out of the tracking area's borders.
Can we also work the phantom radar bug somewhere in here? The only reference of it so far has been on my talk page for yonks. I could never think of how to slip it in.
- NKF
One thing you might want to check with that bug is that it might go away when you complete any new build on the site, not just a new radar - as when I was playing with setting the radars to 100% detection rates, those got reset with a new build, whether it was another radar, or an alien containment facility (to take the example I happened to test).
If the game files suggest ranges of 1500 miles for the small radar, it then opens the reverse question - in practise I have definitely reguarly had previously detected UFOs move out to larger ranges than that, and wander around for an hour or two without dropping off, which happens almost always once they are outside something closer to 2000 miles. Maybe the detection is fixed to the number in the files, and tracking is an extra 33%. This would seem to make it less likely there is a size of UFO factor (although I guess small or medium might use it at 100%, and battleships might have a >100% factor to increase the range they can be detected in just as easily as having a reduction applied to the smaller craft). Cant really think of any decent way to test this either way though.
--Sfnhltb 21:29, 26 February 2007 (PST)
Note also that as far as my testing and experience goes, I dont think the UFOs disappear no matter what range they are at, except when the half hour check comes up. One example I saw recently I had an interceptor chase from my only base in Budapest (short radar), I called off the pursuit in central africa (maybe 3000 miles south, well out of short radar range) while the craft was a shortish distance away, but not catching it up. This was at around 20:35, at 21:00 with my craft nearly at the base, the UFO finally disappeared - it had gone past South Africa on the way to Antartica by this point.
I have noticed UFOs disappear off the radar twice in about 40 or 50 tests at other times (and there might well have been more when I wasnt paying attention), but its fairly rare for that to happen, and I would still suggest it is just them ending the mission, rather than anything different happening with the detection/tracking rules.
--Sfnhltb 21:40, 26 February 2007 (PST)
Well, blow me down, you're right. The stats are reset on the construction of any new facility. Mind you, the thought of testing this with non-radar modules never crossed my mind when I discovered this little bug. It seems to only affect the base where the module was constructed, so it won't change any existing module-less radar effects for other bases.
This certainly reduces the lifespan of the phantom radar a bit. I suppose it can still be useful in two situations, the first is when you're waiting for a new radar to be built but you need the space. The other is once you've finalised the base and no longer want to make any changes to it.
Heh, I've always said that this game often surprises you no matter how much you think you know it inside and out, and that still holds true.
- NKF
Losing Contact
- If the UFO simply goes beyond your tracking range it will just vanish. If it circles around and re-enters this range, it'll reappear instantly.
I am reasonably confident this isnt the case, see above notes for how far they can go at times and still not be lost of radar. What might happen is that a detected UFO that leaves covered airspace disappears at the end of a 30 minutes segment. It might then 100% reappear 30 minutes later (or at any later check point) if it comes back inside any of your radar ranges - i.e. you dont have to reroll a 10% chance for a small radar to respot it when it comes back.
This would make a lot of sense - it could explain why craft radar seem so good at spotting UFOs, i.e. because you usually send craft after an already spotted UFO. This would suggest that craft might not be so much better at spotting UFOs (they might be anyway) because of this effect. If this model of detection/tracking behaviour is correct it breaks down like this:
- Previously undetected UFOs, use the basic range of 1500/2250 for radars, and you must roll your 10/20/30% chance to spot it every 30 minutes
- Previously detected UFOs, inside the (33%) extended tracking range at a 30 minute tracking checkpoint will always stay detected, no new roll is needed
- Previously detected UFOs, outside the extended tracking range will stay on screen, no matter where they go, until the next 30 minute tracking checks are made
- Previously detected UFOs that have since dropped off track due to range, will reappear if they are in range of any radar systems extended tracking range when any tracking check is made
- If a UFO ends its mission, it will immediately disappear off track from anywhere, this can happen at any time (I think)
Anyone see any holes in this, or ways to test things that havent been confirmed - quite a bit is speculation, as I cant think of any way to know what the UFOs are actually doing except while they are detected. Maybe a two base setup with one Hyperwave Detector, and the other base with radars can do something here, wait for a UFO to come in range of the Hyperwave but with a mission to go near the Radar and see if that confirms the 100% repick up (assuming it disappears in between the coverages at the 30 minute checkpoint as expected). Could take a while to find a craft to match that profile though, but once you do could repeat run a few times to confirm the behaviour, or prove that I am talking nonsense, as applicable.
--Sfnhltb 22:04, 26 February 2007 (PST)