Some legitimate customers had problems with this though if they made certain changes to their own phone, such as replacing the battery and / or antenna.

By November 1920 Theremin had given his first public concert with the instrument, now modified with a horizontal volume antenna replacing the earlier foot-operated volume control.

Wireless Type II cards often had a plastic shroud that jutted out from the end of the card to house the antenna.

# The Developmental Prototype ( DP ) had 18 antenna elements, organized in three columns by six rows.

# The Filled Developmental Prototype ( FDP ) had 48 antenna units arrayed in six columns by eight rows, with 960 kW of transmitter power.

Most used the UHF spectrum and had a transmit Yagi antenna on the port wing and a receiver yagi antenna on the starboard wing.

The transmitter had digital to analog converters on the PCI bus feeding an up converter ( mixer ) that led to a power amplifier and antenna.

Don Dwiggins, in his biography of Paul Mantz ( who assisted Earhart and Noonan in their flight planning ), noted that the aviators had cut off their long-wire antenna, due to the annoyance of having to crank it back into the aircraft after each use.

Although they wanted to avoid postproduction effects work, the opticals team had to recolor the antenna ball in a blue hue, as the original orange looked too much like a spinning basketball.

By October 2011, the radar antenna arrays had been dismantled and removed from the deactivated station, but microwave towers and various buildings remained.

Beckley had the first " community antenna " TV system in the United States, a forerunner of cable TV.

Produced by King and broadcast to many countries worldwide with HBO's antenna, The Thrilla in Manila had a tremendous media following.

The antenna was a cylindrical parabolic reflector made of zinc sheet metal supported by a wooden frame, and had a spark-gap excited dipole along the focal line.

Since this circuit lacked any frequency-selective elements besides the broad resonance of the antenna, it had little ability to reject unwanted stations, so all stations within a wide band of frequencies were heard in the earphone ( in practice the most powerful usually drowns out the others ).

The lander had the shape of a shallow bowl with a diameter of 1m and a depth of 0. 25 m. The cover of the lander was hinged and folded open to reveal the interior of the craft which holds a UHF antenna, the 0. 75 m long robot arm, and the scientific equipment.

Certain frequencies were designated for Class A only ( see FM broadcasting ), which had a limit of three kilowatts of effective radiated power ( ERP ) and an antenna height limit for the center of radiation of 300 feet ( 91. 4 m ) height above average terrain ( HAAT ).

Mathematically, the extremely wideband excitation provided by the spark gap was bandpass filtered by the self-oscillating antenna side circuit, which because of its simple construction, also had a relatively broad and badly controlled filter characteristic.

With virtually all other systems, all of the power to operate the headphones had to come from the antenna circuit itself, which tended to " damp " the tuned circuits, limiting their ability to separate stations ( distinguish discrete frequencies ).

nearly identical to the Venera 1 design, a cylindrical body about 2 meters high with two solar panel wings, a 2. 33 meter high-gain net antenna, and a long antenna arm, and had a mass of about 650 kg.

It had an eight-panel antenna array measuring 35 feet by 7 feet ( 11 m by 2 m ).

It operated throughout the flight, but problems were encountered with Challenger ’ s K < sub > u </ sub > band antenna, and therefore much of the data had to be recorded on board the orbiter rather than transmitted to Earth in real-time as was originally planned.

Pickard's loop antenna was revolutionary in that he found that it had directional properties that could be used to reduce interference to the intended wireless communications.

A K < sub > u </ sub >- band antenna for communications was deployed on Flight Day 2, but it failed to respond properly and had to be stowed for the remainder of the mission.

The antenna rotates at a steady rate, sweeping the local airspace with a narrow vertical fan-shaped beam, to detect aircraft at all altitudes.

The rotating antenna radiates a vertical fan-shaped beam.

Most 2D surveillance radars use a spoiled parabolic antenna with a narrow azimuthal beamwidth and wide vertical beamwidth.

An antenna is placed on each side of the net perpendicular to the sideline and is a vertical extension of the side boundary of the court.

As the fan antenna is rotated about a vertical axis, it can illuminate targets only if they are 70 ° or less from the horizontal plane.

For example, a vertical monopole antenna requires a ground plane that often consists of an interconnected network of wires running radially away from the base of the antenna for a distance about equal to the height of the antenna.

The radiation pattern referred to above is usually the horizontal radiation pattern, which is plotted as a function of azimuth about the antenna, although the vertical radiation pattern may also have a main lobe.

In telecommunication, a periscope antenna is an antenna configuration in which the transmitting antenna is oriented to produce a vertical radiation pattern, and a flat or off-axis parabolic reflector, mounted above the transmitting antenna, is used to direct the beam in a horizontal path toward the receiving antenna.

For Rayleigh fading with a vertical receive antenna with equal sensitivity in all directions, this has been shown to be:

Diagram of the electric field s ( E ) and magnetic field s ( H ) of radio waves emitted by a Monopole antenna | monopole radio transmitting antenna ( radio ) | antenna ( small dark vertical line in the center ).

Early RDF systems normally used a loop antenna, a small loop of metal wire that is mounted so it can be rotated around a vertical axis.

Vertical antennas must be used because VLF waves propagate in vertical polarization, but a quarter-wave vertical antenna at 30 kHz would be 2. 5 kilometers high.

Either the towers themselves or vertical wires serve as monopole radiators, and the horizontal cables form a capacitive top-load to increase the efficiency of the antenna.

Because of soil resistance, counterpoise systems are often used, consisting of radial networks of copper cables supported several feet above the ground under the antenna, extending out radially from the mast or vertical element.

Many antenna types, such as the umbrella antenna, use capacitive top-loading ( a " top hat "), in the form of a network of horizontal wires attached to the top of the vertical radiator.

In electromagnetic radiation ( such as microwaves from an antenna, shown here ) the term applies only to the parts of the electromagnetic field that radiate into infinite space and decrease in intensity by an inverse-square law of power, so that the total radiation energy that crosses through an imaginary spherical surface is the same, no matter how far away from the antenna the spherical surface is drawn.

When any wire ( or other conducting object such as an antenna ) conducts alternating current, electromagnetic radiation is propagated at the same frequency as the electric current.

In practice, an isotropic antenna cannot exist, as equal radiation in all directions would be a violation of the Helmholtz wave equation.

Radio astronomy and radar systems often use dielectric lenses, commonly called a lens antenna to refract electromagnetic radiation into a collector antenna.

In electromagnetic radiation ( such as microwaves from an antenna, shown here ) the term " radiation " applies only to the parts of the electromagnetic field that radiate into infinite space and decrease in intensity by an inverse-square law of power, so that the total radiation energy that crosses through an imaginary spherical surface is the same, no matter how far away from the antenna the spherical surface is drawn.

In telecommunications, antenna blind cone ( sometimes called a cone of silence ) is the volume of space, usually approximately conical with its vertex at the antenna, that cannot be scanned by an antenna because of limitations of the antenna radiation pattern and mount.

The horizontal radiation pattern of an ARSR antenna is very narrow.

A number of different types of antenna elements can be utilized to produce circularly polarized ( or nearly so ) radiation ; following Balanis, one can use dipole elements:

In telecommunication, the effective height of an antenna is the height of the antenna's center of radiation above the ground.

For an antenna with a symmetrical current distribution, the center of radiation is the center of the distribution.

For an antenna with asymmetrical current distribution, the center of radiation is the center of current moments when viewed from points near the direction of maximum radiation.

In a monopole antenna, the radiation pattern of the monopole plus the virtual " image antenna " make it appear as a two element center-fed dipole antenna.