For quite some time now I have suspected these danged cell phones do things we are not aware of. Here’s why:
I do EMC testing for a lighting manufacturer. We (and others) have to comply with FCC limits and those limits span a range of frequencies. We test for “noise” on the power leads known as “conducted emissions”, and we test for “radiated emissions where electrical “noise” gets broadcast or sent out into the air.
The radiated emission test is done in a high-dollar EMC chamber or a fancy Faraday cage that was talked about yesterday. That chamber is designed for 100dB of noise suppression. It keeps radio and TV signals out and other electrical background crap that may be occurring within the building. We want to be looking at any noise coming from our product and not the local radio station that plays sheep-breedin’ music. (Sorry country music fans.)
The chamber works superbly, however, it is not perfect as there are some small wall penetrations for product power and lighting. Once in a blue moon a signal will sneak in. The most common offender is a cell phone signal.
The upper part of our FCC radiated test frequency runs from 300 MHz to 1 GHz. The FCC allocated cellular phone frequency is roughly 840 to 880 MHz. If someone in my lab happens to key a cell phone while the spectrum analyzer runs across the above mentioned cell phone frequency, that signal will get picked up and will be a big 5x5 if the chamber door is open.
Several times when working all alone (typical) I’ll get a cell signal peak on the analyzer screen. Now mind you...my phone (Android) is in the room with me...but I’m not using it! In addition there’s usually no one else around within a radius of at least 100 feet.
I’ve concluded my phone is sending some THING some WHERE. All on it’s own. One time doing a continuous scan rate of that high frequency, a cell phone peak was persistent. I took my phone and walked out of the lab but still within view of the analyzer screen. The further away I got the more degradation of the signal peak.
Now what’s going with this??
updates on apps? updating location in google? what’s on your phone? there should be a log like on a pc?
That phone/tower connection is what enables tracking your phone's approximate location over time, as long as it is on.
Is it possible your phone is sending a GPS signal even when it’s turned off?
Gosh, I think you know more is going on.
“I’ll get a cell signal peak on the analyzer screen”
Most likely pinging the network. Nothing like a random spike in a long acquisition.