Why does a radio signal of a FM radio improve when the hand gets closer to its antenna?
In: Physics
Your body works as an antenna that can receive and transmit radio signals. By touching the antenna you are improving the signal by making the antenna larger. Similar to how you can put your car alarm under your chin to send the signal farther.
* Something called “multi-path interference”.
* When radio waves are broadcast from the tower, they shoot out in all directions.
* Some of the waves are pointed directly at the antenna of your radio.
* Many of them are not and bounce off of the ground or other objects before getting to your radio.
* If you think about the physical path these waves take from the tower to your radio you can see that the bounced signals take a longer path than the straight ones do.
* This can create interference at the radio.
* Two copies of the same signal show up but one is slightly behind the other.
* If you think about how waves work, they are alternating moments of high power and low power.
* If a high power moment in one wave happens at the same time as a low power moment of another copy of that wave, they will cancel each other out a little bit.
* This can cause a poor signal.
* ***When you get close to the antenna, you are blocking a lot of the bounced signals that cause interference.***
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