romikgosai/squad_modified_2 huggingface dataset:
A Yagi-Uda array uses passive elements to greatly increase gain. It is built along a support boom that is pointed toward the signal, and thus sees no induced signal and does not contribute to the antenna's operation. The end closer to the source is referred to as the front. Near the rear is a single active element, typically a half-wave dipole or folded dipole. Passive elements are arranged in front (directors) and behind (reflectors) the active element along the boom. The Yagi has the inherent quality that it becomes increasingly directional, and thus has higher gain, as the number of elements increases. However, this also makes it increasingly sensitive to changes in frequency; if the signal frequency changes, not only does the active element receive less energy directly, but all of the passive elements adding to that signal also decrease their output as well and their signals no longer reach the active element in-phase.

Q1: What can take advantage of these elements to add more gain?
A1: Yagi-Uda array
Q2: Does this device improve the operation of the antenna?
A2: does not contribute
Q3: What is the name for passive elements nearer to the source of the signal?
A3: directors
Q4: Adding more elements to a Yagi-Uda would have what effect?
A4: increasingly directional
It is also possible to use multiple active elements and combine them together with transmission lines to produce a similar system where the phases add up to reinforce the output. The antenna array and very similar reflective array antenna consist of multiple elements, often half-wave dipoles, spaced out on a plane and wired together with transmission lines with specific phase lengths to produce a single in-phase signal at the output. The log-periodic antenna is a more complex design that uses multiple in-line elements similar in appearance to the Yagi-Uda but using transmission lines between the elements to produce the output.

Q1: What can be paired with transmission lines to create phases that would support output?
A1: active elements
Q2: What is the most common element used to create a single in phase signal?
A2: half-wave dipoles
Q3: What must be precise in order to create this signal at output?
A3: phase lengths
Q4: What is a more complicated occurrence of the single in-phase producing antenna?
A4: log-periodic
Reflection of the original signal also occurs when it hits an extended conductive surface, in a fashion similar to a mirror. This effect can also be used to increase signal through the use of a reflector, normally placed behind the active element and spaced so the reflected signal reaches the element in-phase. Generally the reflector will remain highly reflective even if it is not solid; gaps less than 1⁄10 generally have little effect on the outcome. For this reason, reflectors often take the form of wire meshes or rows of passive elements, which makes them lighter and less subject to wind. The parabolic reflector is perhaps the best known example of a reflector-based antenna, which has an effective area far greater than the active element alone.

Q1: If you wanted to somehow clone the original signal you could use?
A1: extended conductive surface
Q2: What effect would the use of a reflector have on a signal?
A2: increase
Q3: What allowance can be made for gaps without loss of performance?
A3: less than 1⁄10
Q4: What is the most recognized type of an antenna that has its basis in reflection?
A4: parabolic reflector
Another extreme case of impedance matching occurs when using a small loop antenna (usually, but not always, for receiving) at a relatively low frequency where it appears almost as a pure inductor. Resonating such an inductor with a capacitor at the frequency of operation not only cancels the reactance but greatly magnifies the very small radiation resistance of such a loop.[citation needed] This is implemented in most AM broadcast receivers, with a small ferrite loop antenna resonated by a capacitor which is varied along with the receiver tuning in order to maintain resonance over the AM broadcast band

Q1: What magnifies the small radiation resistance of a loop?
A1: a capacitor at the frequency of operation
Q2: What is resonated by a capacitor along with the receiver tuning that maintains resonance over the AM broadcast band?
A2: small ferrite loop antenna
Q3: What is used in most AM broadcaster receivers?
A3: loop
Q4: When using a small loop antenna at a low frequency, what may occur?
A4: impedance matching
Antenna tuning generally refers to cancellation of any reactance seen at the antenna terminals, leaving only a resistive impedance which might or might not be exactly the desired impedance (that of the transmission line). Although an antenna may be designed to have a purely resistive feedpoint impedance (such as a dipole 97% of a half wavelength long) this might not be exactly true at the frequency that it is eventually used at. In some cases the physical length of the antenna can be "trimmed" to obtain a pure resistance. On the other hand, the addition of a series inductance or parallel capacitance can be used to cancel a residual capacitative or inductive reactance, respectively.

Q1: What is left after antenna tuning?
A1: resistive impedance
Q2: Where does cancellation of any reactance seen?
A2: antenna terminals
Q3: What can be used to cancel a inductibe reactance or residual capacitative?
A3: parallel capacitance
Q4: What is an antenna designed to have?
A4: purely resistive feedpoint
Although a resonant antenna has a purely resistive feed-point impedance at a particular frequency, many (if not most) applications require using an antenna over a range of frequencies. An antenna's bandwidth specifies the range of frequencies over which its performance does not suffer due to a poor impedance match. Also in the case of a Yagi-Uda array, the use of the antenna very far away from its design frequency reduces the antenna's directivity, thus reducing the usable bandwidth regardless of impedance matching.

Q1: What type of antenna has impedance at a specific frequency?
A1: resonant
Q2: What term can be used to refer to the usable spectrum of an antennas frequency?
A2: bandwidth
Q3: What causes the frequencies outside of the bandwidth to be unusable?
A3: impedance match
Q4: What is lessened by the Yagi-Uda design?
A4: directivity
Instead, it is often desired to have an antenna whose impedance does not vary so greatly over a certain bandwidth. It turns out that the amount of reactance seen at the terminals of a resonant antenna when the frequency is shifted, say, by 5%, depends very much on the diameter of the conductor used. A long thin wire used as a half-wave dipole (or quarter wave monopole) will have a reactance significantly greater than the resistive impedance it has at resonance, leading to a poor match and generally unacceptable performance. Making the element using a tube of a diameter perhaps 1/50 of its length, however, results in a reactance at this altered frequency which is not so great, and a much less serious mismatch which will only modestly damage the antenna's net performance. Thus rather thick tubes are typically used for the solid elements of such antennas, including Yagi-Uda arrays.

Q1: What characteristic of the conductor changes the amount of reactance?
A1: diameter
Q2: What characteristic would be better if it were steady?
A2: reactance
Q3: What would be used to create a half wave or quarter wave dipole?
A3: A long thin wire
Q4: What type of tubes are generally used for sturdier always of antennas?
A4: thick tubes
Rather than just using a thick tube, there are similar techniques used to the same effect such as replacing thin wire elements with cages to simulate a thicker element. This widens the bandwidth of the resonance. On the other hand, amateur radio antennas need to operate over several bands which are widely separated from each other. This can often be accomplished simply by connecting resonant elements for the different bands in parallel. Most of the transmitter's power will flow into the resonant element while the others present a high (reactive) impedance and draw little current from the same voltage. A popular solution uses so-called traps consisting of parallel resonant circuits which are strategically placed in breaks along each antenna element. When used at one particular frequency band the trap presents a very high impedance (parallel resonance) effectively truncating the element at that length, making it a proper resonant antenna. At a lower frequency the trap allows the full length of the element to be employed, albeit with a shifted resonant frequency due to the inclusion of the trap's net reactance at that lower frequency.

Q1: What effect do cages have on the spectrum of usable frequencies?
A1: widens
Q2: What type of tubes are generally used for sturdier always of antennas?
A2: cages
Q3: How could one achieve the task of creating an antenna that can be Used over various bands?
A3: connecting resonant elements
Q4: What is an essential for dealing with directing the flow of power?
A4: trap's
Gain is a parameter which measures the degree of directivity of the antenna's radiation pattern. A high-gain antenna will radiate most of its power in a particular direction, while a low-gain antenna will radiate over a wider angle. The antenna gain, or power gain of an antenna is defined as the ratio of the intensity (power per unit surface area)  radiated by the antenna in the direction of its maximum output, at an arbitrary distance, divided by the intensity  radiated at the same distance by a hypothetical isotropic antenna which radiates equal power in all directions. This dimensionless ratio is usually expressed logarithmically in decibels, these units are called "decibels-isotropic" (dBi)

Q1: What is an acknowledgement of the range of possible direction for and antenna?
A1: gain
Q2: What is another way to refer to an antennas gain?
A2: power gain
Q3: What is the meaning of intensity?
A3: power per unit surface area
Q4: What type of an antenna would offer the same level of power to each possible destination?
A4: isotropic
High-gain antennas have the advantage of longer range and better signal quality, but must be aimed carefully at the other antenna. An example of a high-gain antenna is a parabolic dish such as a satellite television antenna. Low-gain antennas have shorter range, but the orientation of the antenna is relatively unimportant. An example of a low-gain antenna is the whip antenna found on portable radios and cordless phones. Antenna gain should not be confused with amplifier gain, a separate parameter measuring the increase in signal power due to an amplifying device.

Q1: Antennas with higher gain have what positive feature?
A1: longer range
Q2: What is a measure of how much efficient is improved by adding a device designed to make something stronger?
A2: amplifier gain
Q3: Dish network Tv takes example of what type of antenna?
A3: parabolic dish
Q4: What type of antenna would be best if placement was tricky?
A4: Low-gain
Due to reciprocity (discussed above) the gain of an antenna used for transmitting must be proportional to its effective area when used for receiving. Consider an antenna with no loss, that is, one whose electrical efficiency is 100%. It can be shown that its effective area averaged over all directions must be equal to λ2/4π, the wavelength squared divided by 4π. Gain is defined such that the average gain over all directions for an antenna with 100% electrical efficiency is equal to 1. Therefore, the effective area Aeff in terms of the gain G in a given direction is given by:

Q1: What must the relationship of an antenna and the receiving area be due to reciprocity?
A1: proportional
Q2: what could an antenna with complete electrical efficiency be said to have?
A2: no loss
Q3: Another term for the effective area is?
A3: Aeff
Q4: hat could an antenna with complete electrical efficiency be said to have?
A4: 1
The radiation pattern of an antenna is a plot of the relative field strength of the radio waves emitted by the antenna at different angles. It is typically represented by a three-dimensional graph, or polar plots of the horizontal and vertical cross sections. The pattern of an ideal isotropic antenna, which radiates equally in all directions, would look like a sphere. Many nondirectional antennas, such as monopoles and dipoles, emit equal power in all horizontal directions, with the power dropping off at higher and lower angles; this is called an omnidirectional pattern and when plotted looks like a torus or donut.

Q1: A plot of the radiation behaviors of an antenna would show what?
A1: relative field strength
Q2: What type of pictoral aid is often used to show this?
A2: three-dimensional graph
Q3:  A sphere shows what type of antennas radiation?
A3: isotropic
Q4: Dipoles are considered to be what antenna type?
A4: nondirectional
Q5: What would an omnidirectional antenna look like if plotted?
A5: donut
The radiation of many antennas shows a pattern of maxima or "lobes" at various angles, separated by "nulls", angles where the radiation falls to zero. This is because the radio waves emitted by different parts of the antenna typically interfere, causing maxima at angles where the radio waves arrive at distant points in phase, and zero radiation at other angles where the radio waves arrive out of phase. In a directional antenna designed to project radio waves in a particular direction, the lobe in that direction is designed larger than the others and is called the "main lobe". The other lobes usually represent unwanted radiation and are called "sidelobes". The axis through the main lobe is called the "principal axis" or "boresight axis".

Q1: What is the term that refers to areas where an antennas radiation is zero?
A1: nulls
Q2: What do radio waves do that account for maxima or nulls in an antenna pattern?
A2: interfere
Q3: If you desired to project radio waves to the south, what part of the antenna would you build larger in that direction?
A3: lobe
Q4: What is the main distinction of side lobes?
A4: represent unwanted radiation
As an electro-magnetic wave travels through the different parts of the antenna system (radio, feed line, antenna, free space) it may encounter differences in impedance (E/H, V/I, etc.). At each interface, depending on the impedance match, some fraction of the wave's energy will reflect back to the source, forming a standing wave in the feed line. The ratio of maximum power to minimum power in the wave can be measured and is called the standing wave ratio (SWR). A SWR of 1:1 is ideal. A SWR of 1.5:1 is considered to be marginally acceptable in low power applications where power loss is more critical, although an SWR as high as 6:1 may still be usable with the right equipment. Minimizing impedance differences at each interface (impedance matching) will reduce SWR and maximize power transfer through each part of the antenna system.

Q1: What is one piece that makes up an antenna system?
A1: radio
Q2: What is created by a portion of a radio waves energy reversing?
A2: standing wave
Q3: A term that refers to the highs and lows of power in electro magnetic waves is?
A3: standing wave ratio
Q4: Impedance matching makes an important difference in what antenna function?
A4: power transfer
Efficiency of a transmitting antenna is the ratio of power actually radiated (in all directions) to the power absorbed by the antenna terminals. The power supplied to the antenna terminals which is not radiated is converted into heat. This is usually through loss resistance in the antenna's conductors, but can also be due to dielectric or magnetic core losses in antennas (or antenna systems) using such components. Such loss effectively robs power from the transmitter, requiring a stronger transmitter in order to transmit a signal of a given strength.

Q1: A measure of the power that is useable and the power absorbed by the terminals?
A1: Efficiency
Q2: What happens to the power that is not absorbed by the antenna?
A2: heat
Q3: What can cause that reaction?
A3: magnetic core losses
Q4: What can cause that reaction?
A4: transmitter
For instance, if a transmitter delivers 100 W into an antenna having an efficiency of 80%, then the antenna will radiate 80 W as radio waves and produce 20 W of heat. In order to radiate 100 W of power, one would need to use a transmitter capable of supplying 125 W to the antenna. Note that antenna efficiency is a separate issue from impedance matching, which may also reduce the amount of power radiated using a given transmitter. If an SWR meter reads 150 W of incident power and 50 W of reflected power, that means that 100 W have actually been absorbed by the antenna (ignoring transmission line losses). How much of that power has actually been radiated cannot be directly determined through electrical measurements at (or before) the antenna terminals, but would require (for instance) careful measurement of field strength. Fortunately the loss resistance of antenna conductors such as aluminum rods can be calculated and the efficiency of an antenna using such materials predicted.

Q1: What would need to be placed into the transmitter to create ten W oh warmth?
A1: 100 W
Q2: What would need to be investigated to determine how much power was radiated?
A2: electrical measurements
Q3: What factor may play a hand in lessened power from a transmitter?
A3: impedance matching
However loss resistance will generally affect the feedpoint impedance, adding to its resistive (real) component. That resistance will consist of the sum of the radiation resistance Rr and the loss resistance Rloss. If an rms current I is delivered to the terminals of an antenna, then a power of I2Rr will be radiated and a power of I2Rloss will be lost as heat. Therefore, the efficiency of an antenna is equal to Rr / (Rr + Rloss). Of course only the total resistance Rr + Rloss can be directly measured.

Q1: What can increase the feedpoint impedance of a component?
A1: loss resistance
Q2: The addition of Rr and Rloss equals what?
A2: resistance
Q3: What equation an determine an antennas effectiveness?
A3: Rr / (Rr + Rloss)
Q4: What is the single factor that can be precisely measured?
A4: total resistance
According to reciprocity, the efficiency of an antenna used as a receiving antenna is identical to the efficiency as defined above. The power that an antenna will deliver to a receiver (with a proper impedance match) is reduced by the same amount. In some receiving applications, the very inefficient antennas may have little impact on performance. At low frequencies, for example, atmospheric or man-made noise can mask antenna inefficiency. For example, CCIR Rep. 258-3 indicates man-made noise in a residential setting at 40 MHz is about 28 dB above the thermal noise floor. Consequently, an antenna with a 20 dB loss (due to inefficiency) would have little impact on system noise performance. The loss within the antenna will affect the intended signal and the noise/interference identically, leading to no reduction in signal to noise ratio (SNR).

Q1: What is the median level for measuring atmospheric noise?
A1: thermal noise floor
Q2: In what type of programs would low efficiency antennas not make a difference in effectiveness?
A2: receiving
Q3: At lesser frequencies what can account for incorrect assumptions about efficiency?
A3: man-made noise
Q4: What is SNR?
A4: signal to noise ratio
The definition of antenna gain or power gain already includes the effect of the antenna's efficiency. Therefore, if one is trying to radiate a signal toward a receiver using a transmitter of a given power, one need only compare the gain of various antennas rather than considering the efficiency as well. This is likewise true for a receiving antenna at very high (especially microwave) frequencies, where the point is to receive a signal which is strong compared to the receiver's noise temperature. However, in the case of a directional antenna used for receiving signals with the intention of rejecting interference from different directions, one is no longer concerned with the antenna efficiency, as discussed above. In this case, rather than quoting the antenna gain, one would be more concerned with the directive gain which does not include the effect of antenna (in)efficiency. The directive gain of an antenna can be computed from the published gain divided by the antenna's efficiency.

Q1: What else is also known as power gain?
A1: antenna gain
Q2: What is used to signal toward a reciever?
A2: transmitter
Q3: Which gain does not iclude the effect of an antenna?
A3: directive gain
Q4: Wats divided by the antennas efficiency?
A4: published gain
This is fortunate, since antennas at lower frequencies which are not rather large (a good fraction of a wavelength in size) are inevitably inefficient (due to the small radiation resistance Rr of small antennas). Most AM broadcast radios (except for car radios) take advantage of this principle by including a small loop antenna for reception which has an extremely poor efficiency. Using such an inefficient antenna at this low frequency (530–1650 kHz) thus has little effect on the receiver's net performance, but simply requires greater amplification by the receiver's electronics. Contrast this tiny component to the massive and very tall towers used at AM broadcast stations for transmitting at the very same frequency, where every percentage point of reduced antenna efficiency entails a substantial cost.

Q1: Small and minimal frequency antennas are know to be what?
A1: inefficient
Q2: What is added to to increase ability for reception?
A2: small loop antenna
Q3: How would this antenna rate in the greater scheme of things?
A3: little effect
Q4: When talking about much larger network what effect can reduced antenna effectiveness have?
A4: substantial cost
The polarization of an antenna refers to the orientation of the electric field (E-plane) of the radio wave with respect to the Earth's surface and is determined by the physical structure of the antenna and by its orientation; note that this designation is totally distinct from the antenna's directionality. Thus, a simple straight wire antenna will have one polarization when mounted vertically, and a different polarization when mounted horizontally. As a transverse wave, the magnetic field of a radio wave is at right angles to that of the electric field, but by convention, talk of an antenna's "polarization" is understood to refer to the direction of the electric field.

Q1: How many polarizations will a antenna have when mounted vertically?
A1: one
Q2: What is another name for electric-field?
A2: E-plane
Q3: When is a magnetic fields right angles to a electrical field?
A3: transverse wave
Q4: Whats understood in reference of direction of an E-plane?
A4: polarization
Reflections generally affect polarization. For radio waves, one important reflector is the ionosphere which can change the wave's polarization. Thus for signals received following reflection by the ionosphere (a skywave), a consistent polarization cannot be expected. For line-of-sight communications or ground wave propagation, horizontally or vertically polarized transmissions generally remain in about the same polarization state at the receiving location. Matching the receiving antenna's polarization to that of the transmitter can make a very substantial difference in received signal strength.

Q1: What mostly affects polarization?
A1: Reflections
Q2: What reflector can change the waves polarization?
A2: ionosphere
Q3: What will you be matching with the  receiving antenna's polarization?
A3: transmitter
Q4: What stays the same regarding polarization state at the recieving location?
A4: polarized transmissions
Q5: What is the name used for signals recieved following reflection by the ionosphere?
A5: a skywave