Critical hours for radio stations is the time from sunrise to two hours after sunrise, and from two hours before sunset until sunset, local time. During this time, certain American radio stations may be operating with reduced power as a result of Section 73.187 of the Federal Communications Commission’s rules.
Why do most AM stations power down at night?
Most AM radio stations are required by the FCC’s rules to reduce their power or cease operating at night in order to avoid interference to other AM stations. … However, during nighttime hours the AM signals can travel over hundreds of miles by reflection from the ionosphere, a phenomenon called “skywave” propagation.
What are critical hours?
For AM broadcast stations, the term critical hours refers to the time periods of sunrise to two hours after sunrise, and two hours before sunset to sunset.
Is AM radio going away?
On October 27, 2020, the FCC voted to allow AM stations to eliminate their analog transmissions and convert to all-digital operation, with the requirement that stations making the change had to continue to make programming available over “at least one free over-the-air digital programming stream that is comparable to …
What is the most powerful AM radio station?
The following is a list of radio stations in the United States that are authorized to run 50 kW (50,000 watts) of power. This is the highest power authorized to any AM station in the United States.
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List of 50 kW AM radio stations in the United States.
| Call sign | KCBQ |
|---|---|
| Frequency | 1170 kHz |
| Community of License | San Diego, California |
| Power | 50 kW-D, 2.9 kW-N, DA2 (Class B) |
Do TV stations reduce power at night?
Stations do not reduced power at night or any other time except during the rare time before a partial equiptment failure is fixed.
Why is AM radio so bad?
AM stands for Amplitude Modulation and has poorer sound quality compared with FM, but it is cheaper to transmit and can be sent over long distances — especially at night. The lower frequencies of the band we use for AM signals creates a wavelength that is extremely large.
Are AM radio stations digital?
Standard AM/FM radios are not able to receive digital radio. All your favourite ABC stations are on digital radio (where available).
Is broadcasting AM radio legal?
UNLICENSED LEGAL AM
The legal limit for AM broadcasting is 100 milliwatts, with a maximum antenna length of about 10 feet (this is highlighted in Part 15 as well). … Though we haven’t seen every low power AM transmitter out on the market, what we have seen comes nowhere close to that kind of coverage radius.
Which is stronger AM or FM?
FM radio, always remains at constant amplitude, so signal strength does not change. FM uses a higher frequency range and a bigger bandwidth than AM. … This means that an FM station can transmit 15 times as much information as an AM station and explains why music sounds so much better on FM.
How far can a 50000 watt AM radio station reach?
For most AM radio stations, which are only licensed to use 5,000 watts of power or less, these radio stations are heard only within a 30 to 50 mile radius. The most powerful 50,000 watt AM radio stations can be heard within a hundred miles or further in the daytime.
Why does AM radio work better at night?
Certain radio stations, however, especially the short-wave and AM bands, can travel much farther. Short-wave can circle the globe, and AM stations transmit hundreds of miles at night. … You can pick up some radio stations better at night because the reflection characteristics of the ionosphere are better at night.
Why does AM radio exist?
The decline in AM audio was due more to regulation than to method of modulation. One aspect of radio not understood by most listeners is the concept of occupied bandwidth, or the amount of spectrum that a station uses to transmit its signal. … It displays signals within a specified range of frequencies.