My community was recently over-flown by one of those fake cell tower in an airplane. These are used to keep tabs on where people are, rather than eaves dropping (they only displace your real tower for a short time.) Their presence can be detected with a little situational awareness, and familiarity with typical signal strength in locations you frequent.
The first step is getting your phone to give you more information about signal than the usual bars. The iPhone has this capability built into it.. When in “field test mode” the bars are replaced with a numeric signal strength indicator.
To enable field test mode dial *3001#12345#* then press dial. To make it stay that way longer than a few minutes, hardware-reset the iPhone by holding the front button and top button at the same time for 7 seconds, immediately after enabling field test mode. The bars will be restored on the following hard reset. (This works on IOS 5 and 6 for sure, I’ve read it works on IOS 4 as well, no idea about IOS 7 or 8, I refuse to run them.) For Android there are free apps that do the same thing in a widget.
The next step is to become familiar with your surroundings by monitoring signal strength periodically. Signal from real towers does naturally fluctuate some, by varying amounts, so it takes a bit of effort to figure out what is normal, and you’ll need to do it at work, at home and wherever else you spend a lot of time.
I recently got the chance to test my theories when I heard an airplane flying low over my home/office. I looked at the signal meter on my iPhone, it read -74 dBm.. Within a minute of the plane’s sound fading signal returned to -98 (it’s always between -92 and -108 at my desk — the numbers are negative so a lower number means more signal.)
The plane itself was a single prop Cessna (99% sure about the make) one of the four seat models, semi-cantilevered wing above the fuselage, fixed landing gear. It was flying at 600-800′ (best guess, definitely below the 1000′ floor, and there are no airports for miles.) There was nothing visually interesting about it besides that it was flying lower than civilian aircraft are allowed, without special permit. It absolutely was NOT a crop duster!
The antenna array was inside — how’d you like to pilot that thing? Hope there’s a Faraday cage for the pilot to sit in, otherwise he/she likely won’t be able to make babies!
Anyone who has made related observations, or has any questions or other theories please feel free to post them as comments.
An aside, if the aviation radio and other instruments still work while this thing is on (which is almost certainly the case) it thoroughly disproves the notion that cell phones might interfere with avionics, a tower radiates thousands of times as much energy as a handset, and these things must surely exceed the power output allowed for real towers.