UFO Detection

Alien craft regulary enter and leave the Earth's atmosphere. Spotting them and shooting them down is an important goal. Before you worry about shooting them down, first you have to spot them, so you will need to know how to go about this.

Types of Detection Facilities

• Small Radar
• Large Radar
• Hyper-Wave Decoder

The above can be built in your base for the purpose of detecting UFOs nearby. Also all your craft have shorter range radars that can be used to keep contact when chasing a UFO or to sweep an area for either ground based or aerial targets.

Radars

Small Radars cover 300 nautical miles according to the UFOpedia, but in practise the radius that you can track out to equates to approximately the distance between Budapest and Reykjavik, which my atlas tells me is closer to 2000 miles. Detection seems to only occur in a smaller radius, of perhaps 1300-1500 miles. Inside this detection radius they have a base 10% detection chance which is tested every 30 minutes exactly on the half hour, so if you are advancing the game an hour or day at a time you may find it jumps forward to exactly a half hour interval as it spots a new UFO. Building more than one Small Radar does not increase your detection rate, despite it making it look this way in the base information screen.

Large Radars cover 450 nautical miles according to the UFOpedia, it is unknown what this translates to, but it seems reasonable from inference and experience to assume it will be about 3000 miles. Note this translates to a 125% increase in land area covered (as long as it is 150% of the radius, it will be 225% of the area anyway). In line with Small Radars detection is more difficult, so only will pick up new contacts from around 2000-2300 miles. Inside this detection radius they have a base 20% detection chance which is tested every 30 minutes exactly on the half hour, so if you are advancing the game an hour or day at a time you may find it jumps forward to exactly a half hour interval as it spots a new UFO. Building more than one Large Radar does not increase your detection rate, despite it making it look this way in the base information screen.

Large and Small radars add together, so if you have one of each you get 30% short range and 20% long range detection, so until you get Hyperwave Decoders available you might want to build one of each in every base that you want to be detecting aliens for maximum coverage, but any more is a waste.

Note that the radius of detection (but not tracking) and/or the detection chance might be affected by the size of the UFO being searched for, the UFOpedia suggests it has an impact, but this needs to be determined whether it does actually play a part.

Hyperwave Decoder

A high priority research item, these devices obsolete all radars as not only do they have at least as large a range as Large Radars, they work 100% of the time, so you always know when an alien has entered your airspace (for any base with a Decoder, anyway) whenever the first 30 minute detection check comes by and they are still there. Very fast UFOs might still pass through some of your airspace without being detected, if they do it in between checks. The Decoder also provides essential strategic and tactical information about the craft, its mission, and destination etc. All this makes these facilities absolutely critical to your mission.

Craft Radars

Your craft can also detect UFOs via onboard scanners, these seem to have a range of roughly 500 miles, but they do seem to have quite a high detection rate - maybe even 100%. If an alien vessel moves out of range of your land-based detection systems, you may be able to resume tracking by sending one of your ships to where you believe the UFO to be (based on its speed and direction). Craft Radars are also key to locating enemy based, and might be used for spotting landed craft, or scouting areas that are showing high UFO activity in the Graphs section.

Note that ground based radar are poor at detecting landed craft (and dont seem to spot bases at all), where craft can usually find these quite quickly if in the relative small radar area it has. Hyperwave Decoders dont detect bases directly either, but because they are so good at spotting any craft in a large area, and their mission profile, it makes it quickly evident if and where any alien bases are located.

Losing Contact

In most cases you will continue to see a detected UFO until it is outside any of your radar ranges (craft or land based) at a half hour checkpoint. In a few cases they will dissappear off radar at times other than the half hour, this might be when an alien craft decides to end its mission and leave the atmosphere, but there may be something else at play.

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.

UFO Activity Graph

Finally, the UFO activity graphs act as a sort of MUFON, allowing you to see activity that your radars cannot. The graphs are updated every 30 minutes, on the half hour. You could even check the graphs every so often and build zero radars if you wanted, and if you see a blip, send aircraft. This worldwide coverage can be easily used this way for the first few months. After that, UFO activity becomes too intense and the graphs lose their resolution, but by that time you should aim to have decoders already built, or on the way.