Yes NASA can receive a ~10 watt transmitter from 10 billion miles away. To do so they use very big, very directional antennas on both sides, with the advantage of not having any other ~10 watt transmitters near the direction of their 10 billion mile away target transmitter and a lot of signal processors. That is only when receiving from their deep space vehicles. When sending they are using a lot more than 10 watts. Also their data rate makes a 9600 baud modem look fast. But your Wi-Fi card is transmitting at 100mW or 0.1 watt omni directional pushing 11 or 54Mbps with a lot of other transmitters on the same band near by. All RF communications are exercises in Signal to Noise. In most urban environments there is a lot of transmitters on the 2.4GHz band of Wi-Fi, other wireless clients and AP, cordless phones, microwave ovens etc. If you can attenuate your Wi-Fi signal by 3-6dB, you are down in the noise and it would take your 'someone' a lot longer to even identify your signal and separate it from the noise. It is not just a war driver with a Pringles(r) can going by, but a dedicated RF sniffing van that has to park there for several days.
Besides the 'paint' is not a complete Faraday cage, but more of a 'stealth coating' optimized to attenuate RF in the Wi-Fi band.
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Yes NASA can receive a ~10 watt transmitter from 10 billion miles away. To do so they use very big, very directional antennas on both sides, with the advantage of not having any other ~10 watt transmitters near the direction of their 10 billion mile away target transmitter and a lot of signal processors. That is only when receiving from their deep space vehicles. When sending they are using a lot more than 10 watts. Also their data rate makes a 9600 baud modem look fast. But your Wi-Fi card is transmitting at 100mW or 0.1 watt omni directional pushing 11 or 54Mbps with a lot of other transmitters on the same band near by. All RF communications are exercises in Signal to Noise. In most urban environments there is a lot of transmitters on the 2.4GHz band of Wi-Fi, other wireless clients and AP, cordless phones, microwave ovens etc. If you can attenuate your Wi-Fi signal by 3-6dB, you are down in the noise and it would take your 'someone' a lot longer to even identify your signal and separate it from the noise. It is not just a war driver with a Pringles(r) can going by, but a dedicated RF sniffing van that has to park there for several days.
Besides the 'paint' is not a complete Faraday cage, but more of a 'stealth coating' optimized to attenuate RF in the Wi-Fi band.