FM clarification

[RF community]

Hi,

     I've the following doubt;

                                         If an AM station transmits in certain frequency, it indicates that frequency is the carrier frequency used. But if an FM station says that it transmits in 93.5MHz, what is that frequency about? In an FM frequency cannot be constant. Then what does that 93.5 MHz mean? How about the design of my antenna?

[David S.]

Hi RF -

93.5 MHz is the carrier frequency for the FM signal.  This is the frequency about which your modulating signal oscillates.  So if the message (or modulating signal) has a 1 MHz bandwidth, then your transmitted signal will oscillate between 93.0 and 94.0 MHz.

I can't provide any advice on antenna design, but Wikipedia is always a good place to start researching.  The FM article also provides three external links that describe FM modulation in greater detail.  The best resource, however, is probably an in-depth text on the art and science of antenna design, as the practice is very difficult and often tricky.

Good luck!

[RF community]

Hi David,

             Thank you so much.