- #1
ndesk1900
- 4
- 0
Hi All,
Always wondered a few things about radio transmission, hoping to get some questions answered.
1. Is there a reason why certain frequencies are free to use by everyone and certain ones are reserved? Is it something to do with the fact that the cost (or means) to send signals on certain frequencies are more (or less) available? Also, what stops someone from broadcasting something on a reserved frequency, is it some kind of encryption that radio stations use?
2. When i am listening to 100.1 Mhz FM means you are frequency modulating a carrier wave of frequency 100.1 right?
3. When buying bandwidth we usually buy a small slot of frequencies (and not just one). I know one of the reasons for that is there should be no interference from one broadcaster to the other. Is another reason for this that "while frequency modulation of the signal, frequency of the carrier signal may change (say +/- 5 Hz) so they need that gap (or bandwidth) to transfer data. More the (gap or) bandwidth, more the data they can transfer." Is this correct reasoning?
If this reasoning is true is it correct to say that AM broadcasters don't need as much of a gap (or bandwidth) as FM broadcasters as they are using amplitude and not frequency to encode data so in effect its unlikely they will interfere with other frequencies.
Thanks
Always wondered a few things about radio transmission, hoping to get some questions answered.
1. Is there a reason why certain frequencies are free to use by everyone and certain ones are reserved? Is it something to do with the fact that the cost (or means) to send signals on certain frequencies are more (or less) available? Also, what stops someone from broadcasting something on a reserved frequency, is it some kind of encryption that radio stations use?
2. When i am listening to 100.1 Mhz FM means you are frequency modulating a carrier wave of frequency 100.1 right?
3. When buying bandwidth we usually buy a small slot of frequencies (and not just one). I know one of the reasons for that is there should be no interference from one broadcaster to the other. Is another reason for this that "while frequency modulation of the signal, frequency of the carrier signal may change (say +/- 5 Hz) so they need that gap (or bandwidth) to transfer data. More the (gap or) bandwidth, more the data they can transfer." Is this correct reasoning?
If this reasoning is true is it correct to say that AM broadcasters don't need as much of a gap (or bandwidth) as FM broadcasters as they are using amplitude and not frequency to encode data so in effect its unlikely they will interfere with other frequencies.
Thanks