Hi guys! Earlier this week I was reading that a radio's antenna should be at least a quarter length of the wave length it is trying to receive.
The scanner we got at home can pick up the 136 Mhz freq. , which i believe has a 2.2 meter wave length. a quarter of that would make it about half a meter.
The scanner's antenna on the other hand is only 12 cms long, when i believe it should be 50 cms. long. How is it able to pick up the 136 mhz frequency even though the antenna is not the size it is supposed to be?
on the same note..... the scanner can also pick up 400 - 480 mhz frequencies. My second question is...... shouldnt the radio have an antenna for each frequency it is asked to pick up? by each freq , i mean an antenna for 400 mhz, another antenna for 401 mhz , 402 mhz etc etc. ? what is the physics that makes an antenna pick up so many different frequencies? me thinks if it is 12 cms long it should only be able to pick up 624567620.83 Hz!!
p.s. (299792458) / ( 12 *4 ) = 624567620.83
Thank You for all the replies.
The scanner we got at home can pick up the 136 Mhz freq. , which i believe has a 2.2 meter wave length. a quarter of that would make it about half a meter.
The scanner's antenna on the other hand is only 12 cms long, when i believe it should be 50 cms. long. How is it able to pick up the 136 mhz frequency even though the antenna is not the size it is supposed to be?
on the same note..... the scanner can also pick up 400 - 480 mhz frequencies. My second question is...... shouldnt the radio have an antenna for each frequency it is asked to pick up? by each freq , i mean an antenna for 400 mhz, another antenna for 401 mhz , 402 mhz etc etc. ? what is the physics that makes an antenna pick up so many different frequencies? me thinks if it is 12 cms long it should only be able to pick up 624567620.83 Hz!!
p.s. (299792458) / ( 12 *4 ) = 624567620.83
Thank You for all the replies.