The International Time Bureau ( BIH ) began a time scale, T < sub > m </ sub > or AM, in July 1955, using both local caesium clocks and comparisons to distant clocks using the phase of VLF radio signals.

* AM broadcasting, radio broadcasting using amplitude modulation

* AM ( ABC Radio ), an Australian radio programme

Amplitude modulation ( AM ) is a technique used in electronic communication, most commonly for transmitting information via a radio carrier wave.

Beginning with Reginald Fessenden's audio demonstrations in 1906, it was also the original method used for audio radio transmissions, and remains in use today by many forms of communication —" AM " is often used to refer to the mediumwave broadcast band ( see AM radio ).

Professional touring amplifiers often have input and / or output filtering to sharply limit frequency response beyond ; too much of the amplifier's potential output power would otherwise be wasted on infrasonic and ultrasonic frequencies, and the danger of AM radio interference would increase.

Field modulation of a very high speed AC generator was also used for some early AM radio transmissions .< ref >

In 1998, Belgium had 79 FM radio stations, 7 AM stations and 1 SW station, serving 8. 075 million radios owned in the country.

As of 2001, there were zero AM radio broadcast stations, four FM stations, and one shortwave one.

On July 14, 2005, Tom Biscardi, a long-time Bigfoot enthusiast and CEO of Searching for Bigfoot Inc., appeared on the Coast to Coast AM paranormal radio show and announced that he was " 98 % sure that his group will be able to capture a Bigfoot which they have been tracking in the Happy Camp, California area.

In Baltimore, Orioles games on radio can be heard over WBAL ( 1090 AM ).

Of the approximately 515 radio stations, 454 are AM ; 34, FM ; and 27, shortwave.

The Indians ' flagship radio station is WTAM AM 1100.

The first use for the diode was the demodulation of amplitude modulated ( AM ) radio broadcasts.

In summary, an AM signal consists of alternating positive and negative peaks of a radio carrier wave, whose amplitude or envelope is proportional to the original audio signal.

The diode ( originally a crystal diode ) rectifies the AM radio frequency signal, leaving only the positive peaks of the carrier wave.

Radio DJs or radio personalities introduce and play music that is broadcast on AM, FM, shortwave, digital, or internet radio stations.

While at WERE ( 1300 AM ) in Cleveland, Ohio, DJ Bill Randle was one of the first to introduce Elvis Presley to radio audiences in the northeastern US.

FM enabled the transmission and reception of a wider range of audio frequencies, as well as audio free of " static ", a common problem in AM radio.

He played a jazz record over conventional AM radio, then switched to an FM broadcast.

The signal ( at 42. 8 MHz ) could be heard clearly 100 miles ( 160 km ) away, despite the use of less power than an AM radio station.

With the existence of these many factors, some of them variable, it obviously has never been and is not now possible for the Commission to make assignments of AM stations on a case-to-case basis which will insure against any interference in any circumstances.

All AM stations radiate both skywave and groundwave signals, at all hours ; ;

Because of the difference between daytime and nighttime propagation conditions, it has been necessary to evolve different allocation structures for daytime and nighttime broadcasting in the AM band, with many more stations operating during the day than at night.

As mentioned, the allocation of AM stations represents a balance between protection against interference and the provision of opportunity for an adequate number of stations.

Essentially, the question presented for decision in the present Daytime Skywave proceeding is whether our decision ( in 1938-1939 ) to assign stations on the basis of daytime conditions from sunrise to sunset, is sound as a basis for AM allocations, or whether, in the light of later developments and new understanding, skywave transmission is of such significance during the hours immediately before sunset and after sunrise that this condition should be taken into account, and some stations required to afford protection to other stations during these hours.

Radio broadcast stations: AM 4, FM 6, shortwave 0 ( 2002 )

Radio broadcast stations: AM 2, FM 7, shortwave 0 ( 2007 )

* Broadcast stations: AM 1, FM 2 ( transmitting on 18 different frequencies ), shortwave 0 ( 2006 )

Radio broadcast stations: AM 2, FM 26, shortwave 3 ( 2007 )

In 1998, there had been two AM stations, two FM stations, and no shortwave stations.

Radio broadcast stations: AM 245, FM 582, shortwave 6 ( 2004 )

Radio broadcast stations: AM 0, FM 17, shortwave 0 ( 2006 )

* Broadcast stations: 1, 490 ( 175 AM ; 1, 315 FM ) ( 2006 )

; Radio broadcast stations: AM 42 ( plus 15 repeaters ), FM 14, shortwave 3 ( 1999 )

Many large countries in turn have internal rules on how and where specific subsets of their callsigns can be used ( such as Mexico's XE for AM and XH for FM radio and Television broadcasting ), which are not covered here.

The Marshall Islands have several AM and FM radio stations.

Two radio stations — KMOX, 1120 AM in St. Louis, Missouri, and KABC, 790 AM in Los Angeles — adopted an all-talk show format in 1960, and both claim to be the first to have done so.

These have primarily come from the conversion of AM facilities, most of which formerly had adult standards formats.

It is usually found on FM radio music stations in morning drive, as the actual hot talk formatted stations have only achieved mediocre success as a whole compared to AM or conservative talk radio, or even FM music radio.

The most important talk radio in Brazil is Jovem Pan AM, which have also sports and news broadcasts.

The islands have a number of AM and FM radio stations ( mostly on St. Thomas and St. Croix ) broadcasting music, religious, and news programming.

This is one reason that the aviation industry, and others, have chosen to use AM for communications rather than FM, allowing multiple signals to be broadcast on the same channel.

Many radio transmission sites have backup diesel generators — in the case of amplitude modulation ( AM ) radio transmitters, the load presented by the transmitter changes continuously and instantaneously with the signal level.

Historically, CBC Radio One has broadcast primarily on the AM band, but many stations have moved over to FM.

Over the years, a number of CBC radio transmitters with a majority of them on the AM band have either moved to FM or had shutdown completely.

It is preserved in the 13th century manuscripts Codex Regius and AM 748 I 4to but may have been originally composed in heathen times.

AM Top 40 radio, in particular, became wary of a group that had scored a hit with a song that contained thinly-veiled drug references and whose singles were often deemed too controversial, so Jefferson Airplane never again enjoyed the kind of widespread radio support they would have needed to score more Top Ten hits.

Most Ironman events have a strict time limit of 17 hours to complete the race, where the Ironman race starts at 7: 00 AM, the mandatory swim cut off for the swim is 2 hours 20 minutes, the bike cut off time is 5: 30 PM, and all finishers must complete their marathon by midnight.

There are no AM radio stations based in Blackford County, but plenty of nearby areas have AM stations in broadcast range.

In 2010 the mayor of Washington Park, John Thornton, was found to have been fatally shot ; he was discovered in his car injured on the morning of April 1, 2010, and he died at the hospital at 6 AM.

There have been several organizations in Orangeville throughout its history and in 1876 the local Ancient Free and Accepted Masons ( AF and AM ) Lodge erected the Orangeville Masonic Hall.

These stations are typically located nearby, or they have an exceptional signal, such as Fort Wayne ’ s 50, 000 watt WOWO AM station.

AM General, Crowe Horwath, Martin's Super Markets, and Schurz Communications have corporate headquarters in South Bend.

Several stories have been noted of locals talking on cell phones with evacuated relatives as late as 8: 30-9: 00 AM, stating they felt the worst was over.

Residents only needing to make local calls have dealt with this situation by developing their own communication system using CB radios and portable FM / AM radios.