Connecting the antenna directly to the spark gap produced only a heavily damped pulse train.

Antenna gain is usually defined as the ratio of the power produced by the antenna from a far-field source on the antenna's beam axis to the power produced by a hypothetical lossless isotropic antenna, which is equally sensitive to signals from all directions.

In the late 1960s traffic radars began being produced which used a single antenna.

The sound power produced by the earphone of a crystal set comes solely from the radio station being received, via the radio waves picked up by the antenna.

The height above average terrain for VHF and higher frequencies is extremely important when considering ERP, as the signal coverage ( broadcast range ) produced by a given ERP dramatically increases with antenna height.

Flight path is controlled by producing navigation input to the steering system ( tail fins or gimbaled rocket ) using angle errors produced by the antenna.

The beam of energy produced by an antenna of this size using X-band frequencies occupies a cone that extends about 22 degrees surrounding the line of sight, 44 degrees in total width.

A similar phenomenon occurred on the New Horizons spacecraft ; photons ( thermal infrared ) from the RTG, reflected from the spacecraft's antenna, produced a very small thrust which propelled the spacecraft slightly off course.

Two versions were produced, the mobile SCR-270, and the fixed SCR-271 which used the same electronics but used an antenna with somewhat greater resolution.

As this antenna had an unfavorable vertical radiation pattern, which produced much skywave resulting in a too small fading-free reception area at night, in 1934 a new antenna was installed.

The aperture is defined as the area, oriented perpendicular to the direction of an incoming radio wave, which would intercept the same amount of power from that wave as is produced by the antenna receiving it.

The original transmitter produced an antenna power of 1, 500 watts into a T top wire antenna, located about 1 / 2 mile away, also at the GE plant.

Aerial photographs of the island clearly display large areas of grasslands and park-like savanna upon which the US military has constructed large outdoor facilities such as antenna fields and the airport.

Besides the large broadcast networks ( which are free for anyone with a TV and an antenna ), there are also many networks available only with a subscription to cable or satellite television, like CNN.

The beam has to have a large diameter so that only a small portion of the beam misses the sail due to diffraction and the laser or microwave antenna has to have a good pointing stability so that the craft can tilt its sails fast enough to follow the center of the beam.

Attached by an arm to one side of the base and extending below the spacecraft was a large directional dish antenna.

Communications consisted of a 3 Watt transmitter capable of continuous telemetry operation, the large high gain directional dish antenna, a cylindrical omnidirectional antenna at the top of the instrument mast, and two command antennas, one on the end of either solar panel, which received instructions for midcourse maneuvers and other functions.

Attached by an arm to one side of the base and extending below the spacecraft was a large directional dish antenna.

Communications consisted of a 3 Watt transmitter capable of continuous telemetry operation, the large high gain directional dish antenna, a cylindrical omnidirectional antenna at the top of the instrument mast, and two command antennas, one on the end of either solar panel, which received instructions for midcourse maneuvers and other functions.

In telecommunication, aperture-to-medium coupling loss is the difference between the theoretical antenna gain of a very large antenna, such as the antennas in beyond-the-horizon microwave links, and the gain that can be realized in practice.

That said, it is also used in the Radio Frequency ( RF ) regime for cases in which the antenna is operating in the so-called optical region and is likewise very large relative to a wavelength.

* Another reason for using the Cassegrain design is to increase the focal length of the antenna, to improve the field of view Parabolic reflectors used in dish antennas have a large curvature and short focal length, to locate the focal point near the mouth of the dish, to reduce the length of the supports required to hold the feed structure or secondary reflector.

Higher energy pulses, such as lightning or nuclear EMP simulations, can require a large current clamp or a large antenna which completely surrounds the DUT.

There are a number of devices that can achieve this objective, ranging from a large low-inductance capacitor bank discharged into a single-loop antenna or a microwave generator to an explosively pumped flux compression generator.

An inductively coupled transponder comprises an electronic data carrying device, usually a single microchip, and a large coil that functions as an antenna.

Let the total power radiated from a point source, for example, an omnidirectional isotropic antenna, be P. At large distances from the source ( compared to the size of the source ), this power is distributed over larger and larger spherical surfaces as the distance from the source increases.

An exceptionally large antenna loading coil

Unlike the bidirectional W8JK designs, the ZL Special is essentially a unidirectional beam ; the polar plots of the ZL special and the HB9CV are heart shaped ( cardioid ), while the typical Yagi antenna has a large forward lobe and a smaller back lobe.

Ghosts occur when transmissions bounce off a mountain or other large object, while also arriving at the antenna by a shorter, direct route, with the receiver picking up two signals separated by a delay.

The antenna needs a 3D tree of twin-leads and chokes to connect a single cable to a large number of micro antennas.

Here, we present a common simple proof limited to the approximation of two antennas separated by a large distance compared to the size of the antenna, in a homogeneous medium.

With an operating frequency of 106 MHz and a wavelength of 3 meters this large antenna was required to generate a sufficiently narrow beamwidth to locate enemy aircraft.

For stationary antennas, excessive amounts of ice can de-tune the antenna to the point where its impedance at the input frequency rises drastically, causing voltage standing wave ratio ( VSWR ) to rise as well.

Due to the differences between daytime and nighttime ionospheric propagation at mediumwave frequencies, it is common for AM broadcast stations to change between day ( groundwave ) and night ( skywave ) radiation patterns by switching the phase and power levels supplied to the individual antenna elements ( mast radiators ) daily at sunrise and sunset.

Most United States AM radio stations are required by the Federal Communications Commission ( FCC ) to shut down, reduce power or employ a directional antenna array at night in order to avoid interference with each other due to night-time only long-distance skywave propagation (" skip ").

In the United States, there are six " Local Channel " frequencies, also known as " graveyarders " where nearly every station on those frequencies has the same power and antenna pattern both day and night and, as a result of skywave propagation, there is normally massive co-channel interference in rural areas on these frequencies, often making it difficult, if not impossible, to understand what's being said on the nearest local station on the respective channel, or the other distant stations which are bouncing on the same channel, during the nighttime hours.

The latter antenna delivers good skywave suppression.

For the transmitting antenna, by the definition of gain,, the radiation power density at a distance from the antenna ( i. e. the power passing through unit area ) is

Here is the power density of the incident radiation, and is the antenna aperture or effective area of the antenna ( the area the antenna would need to occupy in order to intercept the observed captured power ).

Here, the gain and effective area of antenna 2 are fixed, because the orientation of this antenna is fixed with respect to the first.

* Sector antenna, to see the area spanned by an antenna on a mobile phone mast

This is because the purpose of the dish element of the antenna is to collect the incident waves over an area and focus them all onto the antenna's actual receiving element, mounted in front of the dish ( and pointed back towards its face ); if the waves are more intense, fewer of them need to be collected to achieve the same intensity at the receiving element.

The general principle underlying all the devices is that a microwave antenna that resides in a urethral catheter is placed in the intraprostatic area of the urethra.

Many of Tampa Bay's radio and television stations broadcast from an antenna farm in the Riverview area, on Boyette Road, southeast of town.

low frequency ground waves can cover an area with a radius of 2000 km about the transmitting antenna.

Damage to Puerto Rico was such that the metropolitan area of San Juan ( including Guaynabo where the WAPA-TV studios sit ) lost power for at least two weeks and the station's antenna was knocked off its foundations.

Due to the nature of radio propagation, this allowed its two beams to be pointed much more accurately than Knickebein from a similarly sized antenna ; the equi-signal area was only about wide at a distance of from the antenna.

: is the area of the antenna aperture, that is, the mouth of the parabolic reflector

* Feed illumination taper-The maximum gain for any aperture antenna is only achieved when the intensity of the radiated beam is constant across the entire aperture area.

To prevent this problem these types of antennas often use an offset feed, where the feed antenna is located to one side, outside the beam area.

* Cellular Mobile Networks: In cellular mobile communication ( GSM & LTE Systems, for instance ), frequency spectrum is a precious resource which is divided into non-overlapping spectrum bands which are assigned to different cells ( In cellular communications, a cell refers to the hexagonal / circular area around the base station antenna ).

A spot beam, in telecommunications parlance, is a satellite signal that is specially concentrated in power ( i. e. sent by a high-gain antenna ) so that it will cover only a limited geographic area on Earth.

DIY DVB-T butterfly antenna, applicable in the so-called core area