Question

Let’s start with a discussion about the use of radiation charts for determining signal strength at given distances. To do this, research FM or AM radio stations in the area, which typically have radiation charts available online. What do you notice about the antenna types used?

Answer 1

Answer:-

FM broadcasting is a method of radio broadcasting using frequency modulation (FM) technology. Invented in 1933 by American engineer Edwin Armstrong, wide-band FM is used worldwide to provide high-fidelity sound over broadcast radio. FM broadcasting is capable of better sound quality than AM broadcasting (under normal listening conditions), the chief competing radio broadcasting technology, so it is used for most music broadcasts. Theoretically wideband AM can offer equally good sound quality, provided the reception conditions are ideal. FM radio stations use the VHF frequencies. The term "FM band" describes the frequency band in a given country which is dedicated to FM broadcasting.

A commercial 35 kW FM radio transmitter built in the late 1980s. It belongs to FM radio station KWNR in Las Vegas, Nevada, and broadcasts at a frequency of 95.5 MHz.

FM broadcasting is a method of radio broadcasting using frequency modulation (FM) technology. Invented in 1933 by American engineer Edwin Armstrong, wide-band FM is used worldwide to provide high-fidelity sound over broadcast radio. FM broadcasting is capable of better sound quality than AM broadcasting (under normal listening conditions), the chief competing radio broadcasting technology, so it is used for most music broadcasts. Theoretically wideband AM can offer equally good sound quality, provided the reception conditions are ideal. FM radio stations use the VHF frequencies. The term "FM band" describes the frequency band in a given country which is dedicated to FM broadcasting.

Contents

• 1Broadcast bands
• 2Modulation characteristics
  • 2.1Modulation
  • 2.2Pre-emphasis and de-emphasis
  • 2.3Stereo FM
  • 2.4Quadraphonic FM
  • 2.5Noise reduction
  • 2.6Other subcarrier services
• 3Reception distance
• 4Adoption of FM broadcasting
  • 4.1United States
  • 4.2Europe
    • 4.2.1United Kingdom
    • 4.2.2Italy
    • 4.2.3Greece
  • 4.3Australia
  • 4.4New Zealand
  • 4.5Trinidad and Tobago
  • 4.6Turkey
  • 4.7Other countries
  • 4.8ITU Conferences about FM
• 5FM broadcasting switch-off
• 6Small-scale use of the FM broadcast band
  • 6.1Consumer use of FM transmitters
  • 6.2Microbroadcasting
  • 6.3Clandestine use of FM transmitters
• 7See also
  • 7.1FM broadcasting by country
  • 7.2FM broadcasting (technical)
  • 7.3Lists
  • 7.4History
• 8See also
• 9References
• 10External links

Broadcast bands[edit]

Main article: FM broadcast band

Throughout the world, the FM broadcast band falls within the VHF part of the radio spectrum. Usually 87.5 to 108.0 MHz is used,^[1] or some portion thereof, with few exceptions:

• In the former Soviet republics, and some former Eastern Bloc countries, the older 65.8–74 MHz band is also used. Assigned frequencies are at intervals of 30 kHz. This band, sometimes referred to as the OIRTband, is slowly being phased out in many countries. In those countries the 87.5–108.0 MHz band is referred to as the CCIR band.
• In Japan, the band 76–95 MHz is used.

The frequency of an FM broadcast station (more strictly its assigned nominal center frequency) is usually an exact multiple of 100 kHz. In most of South Korea, the Americas, the Philippines and the Caribbean, only odd multiples are used. In some parts of Europe, Greenland and Africa, only even multiples are used. In the UK odd or even are used. In Italy, multiples of 50 kHz are used. In most countries the maximum permitted frequency error is specified, the unmodulated carrier should be within 2000 Hz of the assigned frequency.

There are other unusual and obsolete FM broadcasting standards in some countries, including 1, 10, 30, 74, 500, and 300 kHz. However, to minimise inter-channel interference, stations operating from the same or geographically close transmitter sites tend to keep to at least a 500 kHz frequency separation even when closer frequency spacing is technically permitted, with closer tunings reserved for more distantly spaced transmitters, as potentially interfering signals are already more attenuated and so have less effect on neighboring frequencies.

anteena used in fm station:-

FM radio antena is open or closed dipol with asimetric part
(ferite transformer).
So you may build that dipol like in line or rounded.