Skibane wrote:
pianotuna wrote:
I can understand receiving a signal from a more powerful satellite, but how is 1/10 of a watt going to "reply"?
Increasing the receiving gain of the antenna on the satellite reduces the amount of transmit power required from the smartphone.
Having big "ears" makes it easier to "hear" weak signals.
The other thing to keep in mind is the fresnel zone.
While we often think of radio signals as line of sight, there is actually an oblong oval shaped area between the two radios where the signal passes (layperson explanation).
If you have two kids at the end of a football field with walkie-talkies, the ground is blocking a big part of the signal. It's such a short distance that enough signal gets thru but much is lost. Add in trees, hills, buildings, etc... and only a small part of the fresnel zone may be clear to carry the radio signal.
This is why radio towers are tall. As much as possible, they are trying to get above any obstructions that block the fresnel zone.
If you are in an open field, communicating with a radio directly above you, you have a near perfect fresnel zone reducing the amount of signal that is lost.
