The Clock frequency of a PS/2 Keyboard is something between 10 and 17 kHz, if i remember correctly. What service provider do you use?
i dont know if we can work with the informations, then. but we could try to do some math, maybe we find a correlation.

Yeah, playing with high frequencies is an interesting field...youll never know what happens. GSM isnt THAT high (with WLan everything is possible, even transdimensional connections. But its also possible that a connection fails if the devices are 5m away from each other) but its high enough to be quite unpredictable.
Could be that you managed to place you device in the EXACT right angle or something else. Polarity is the thing to take into account here. And much other things.