fm modulation

Discussion in 'Wireless & RF Design' started by rd_aec057, Jul 19, 2005.

  1. rd_aec057

    Thread Starter New Member

    May 2, 2005
    anybody can explain me why fm signals can not be received from far distance from fm station
  2. n9xv

    Senior Member

    Jan 18, 2005
    By FM signals I assume you mean the 88 to 108-MHz VHF broadcast band. These frequencies rely primarily on sky wave propagation rather than ground wave propagation. Sky wave propagation being a function of antenna height. For a given transmitter antenna height, the higher the receiver antenna the better the reception. Although VHF is not quite "line of sight" this priciple is used to calculate reception/communication distances. Rough terrain and buildings can adversely affect the reception path as well.

    Take a look at the spreadsheet attachment.