NEETS 17.txt

The usual range of radiotelephone is from ___ to ___ miles.

Successful transmission of hf signals over a long distance is dependent upon refraction of radio waves by layers of the ___________.

Frequencies above ___ megahertz are not normally refracted by the atmosphere and ground-wave range is minimal.

30

The __________ mode uses a single channel or frequency to exchange information between two or more terminals. Communications is in one direction only.

The _________ mode has one-way flow of information between terminals.

The ______________uses an arrangement of equipment where one terminal is simplex configured and the other uses two channels or frequencies in full duplex.

The ________ mode is a method of operation in which telecommunications between stations takes place simultaneously in both directions using two separate frequencies

__________ is the type of operation in which one station transmits information on one or more channels directed to more than one station and/or unit

_______ occurs when a transmitted electromagnetic wave passes through the receiver antenna and

induces a voltage in the antenna.

Reception

_________ is the ability of the receiver to select a particular frequency of a station from all other station frequencies appearing at the antenna of the receiver.

Selection

__________ is the action of separating the low (audio) frequency intelligence from the high (radio) frequency carrier. A detector circuit is used to accomplish this action.

Detection

_________ is the action of converting the electrical signals to sound waves, which can then be interpreted by your ear as speech, music, and the like.

The ability of a receiver to reproduce weak signals is a function of the __________ of a receiver

__________ is the degree of distinction made by the receiver between the desired signal and unwanted signals

Selectivity

The ________ of a receiver is its ability to accurately reproduce, in its output, the signal that appears at its input.

fidelity

A typical value of IF for an AM communications receiver is _____ kilohertz

The overwhelming danger to date appears to be the hazard from thermal effects, which are a function of intensity of radiation and frequency. This is particularly true in the range of ___ to __ gigahertz.

The distance of one hop for a line-of-sight system is between _____ and ____miles.

HF has a hop distance (skywave) of about ________miles;