a rather silly question

[inquisitive1]

hey guys
i have a rather silly question to ask but believe me i have tried to find its answer where possible but couldnt get a satsifying reply

when we talk of radio communication, why are we only interested in frequencies that are almost similar? why dont we consider the frequencies higher than our frequency of interest for interference?

 

[A.Anand Srinivasan]

what are you referring here by the frequencies that are similar..... are you talking about a band of frequencies or about different modulated signals...........

 

[inquisitive1]

by frequencies i meant modulated signals each having a different carrier frequency
see in this free space there are so many signals but are we only concerned about the signals that are similar in frequency for interference. i want to know why doesnt a signal much distant in frequency spectrum is not of importance to us when we combat interference

 

[flatulent]

Signals that are far away in frequency from what we want can be filtered out.

 

[A.Anand Srinivasan]

one thing you gotta understand is that the modulated signals of interest are passed through many filters before being demodulated and hence most of the signal outside the filters passband (frequencies much distant from the signal of our interest) get attenuated much... so they dont pose that big a problem...... only those frequencies nearby are not attenuated enough and hence pose a problem....

 

[inquisitive1]

ok
thanks for your help
but i knew that already. actually i believe i couldnt convey my point well maybe thats why i didnt get the answer i was looking for
anyways thanks alot for your help guys

 

[segun_oyetunji]

By what i can understand from your question, according to the EM spectrum, waves that operate between 10000Hz and 10^9 Hz are radio waves. So we can't help to go to higher frequencies cos we'll be leaving the radiowave region and we'll be moving over to the microwave region.
Even higher frequencies will take us to to the Infrared region and a frequency of about 100Hz which is lower than the minimum freq of radio wave will launch us into the frequency of electrical power.

Guess we aint no choice but to make do with the frequency bandwidth we've got if we really want to communicate via radio waves.