(B). RF communications, "modulation" is the combination of information or intelligence on to a radio carrier frequency.

Using alternating (not direct current like a battery) radio frequencies are created by the use of the current applied to an electrically conductive material, such as metals. These basic radiation frequencies are often called "carriers."

When you modulatie, or disturb the carrier wave, you create either a bigger or smaller wave (sine wave AM) or you change how often it occurs (cycles per unit of time, FM)

Thus, radio waves are can be defined by their frequency and length. Frequencies are stated in Hertz (cycles per second), while wavelengths are measured in either meters or centimeters.

Radio waves, being electromagnetic waves, and like other type of waves can move at the speed of light when no obstruction are present.

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(C). RF communications, "bandwidth" is the portion of the radio spectrum consumed by a particular emission selection and modulation technique.

Bandwidth refers to FCC or ITU defined radio wave radiation regions (frequency bands) assigned for different purposes. Some bandwidths are unlicensed, as in garage door openers, etc., while most require an FCC license, usually after passing an exam.

One FCC licensed bandwidth with no license but currently $70 is the GRMS.

For more on FCC maps of defined bandwidths, please see FCC Maps for Radio Frequencies

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(D). In an AM broadcast signal using voice there is a carrier with constant amplitude and frequency with complex upper and lower sidebands varying in amplitude and frequency.

When you modulatie, or disturb the carrier wave, (the frequency resulting from current through conductor) you create either a bigger or smaller wave (sine wave AM) or you change how often it occurs (cycles per unit of time, FM).

For AM, you generate the carrier and the disturbance of the carrier, a sine wave. The sine wave appears above the carrier frequency and below the carrier frequency, as a mirror wave. The upper portion above the carrier is called the USB or upper side band, while below the carrier, it is called LSB or the lower side band.

For SSB, the carrier frequency and usually the LSB or lower side band are suppressed, so that all the radio's radiation energy (watts) is directed to the SSB, giving a much larger area where it can be received.

For more information please see Wikipedia article on AM Broadcasting

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(A). In FM communications, the information is applied to the carrier by varying the frequency of the carrier to convey the information to other stations

When you modulatie, or disturb the carrier wave, (the frequency resulting from current through conductor) you create either a bigger or smaller wave (sine wave AM) or you change how often it occurs (cycles per unit of time, FM).

It is the cycles per time that is being manipulated.

For a more explanation, please see Wikipedia article on FM Broadcasting

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(D). A3E, J3E, H3E, F3E.

AM-Voice DSB    A3E  156-470 MHz
SSB-Voice w/o carrier J3E  1605-27500 kHz
USB-Voice w/ carrier  H3E  1605-27500 kHz
FM-Voice       F3E 72-76 MHz

For a table of types of emissions listing, please see the Code of Federal Register on
Title 47 - Telecommunication § 80.207 Classes of emission

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(A). J3E, H3E, F3E, F1B

SSB-Voice w/o carrier J3E  1605-27500 kHz
USB-Voice w/ carrier  H3E  1605-27500 kHz
FM-Voice       F3E 72-76 MHz SITOR (NBDP) TELEX  F1B  DSC, NB-DP 14

For a table of types of emissions listing, please see the Code of Federal Register on
Title 47 - Telecommunication § 80.207 Classes of emission

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