Raibeam Antennas

High current low voltage

Generally, electrical noise receptivity is associated with vertically polarized antennas. However, there is evidence that suggests horizontally polarized antennas are also susceptible to receiving this type of noise. In the case of a horizontally polarized end-fire array consisting of ½ wavelength elements, the degree of receptivity to electrical noise is apparently related to the ratio of the voltage to current amplitudes present on the driven element. For example, experiments have revealed that arrays with a rather high feedpoint impedance - lower current / higher voltage ratio - will be proportionally more susceptible to receiving voltage noise than an array with a low feedpoint impedance - higher current / lower voltage ratio.

The closer the spacing, the higher the coupling will be between resonant elements, resulting in a lower element impedance and a higher current / voltage ratio. Raibeam's critically coupled, closely spaced, dual element driver results in a very low element impedance and a very high current / voltage ratio, thus its overall lower susceptibility to voltage noise reception.

Matching networks

The series capacitor in a traditional gamma-match makes this type of matching network susceptible to receiving noise. Our matching networks do not include this series capacitance. In fact, measurements using a general-usage type DC ohmmeter will show zero ohms. This helps to further reduce the Raibeam's receptivity to noise.

Radiation pattern

Put in simple terms, there two basic types of noise - manmade and natural. Manmade noise is generally thought of as the most common; however natural noise does contribute to the overall noise level to a considerable degree, and both can be found to exist over the entire radio spectrum (broadband noise). Natural noise can be attributed to atmospheric, solar, and universal background radiation.

While manmade and atmospheric noise levels tend to vary somewhat directionally, background radiation noise levels are consistent in every direction. An omni-directional antenna will receive the highest amount of noise, as the total noise is the sum of the noise received from all directions. From this it is easily deduced that the more nulls in the radiation pattern of a given antenna, the lower its noise receptivity will be. The Raibeam's critically coupled drivers produce deep side and back nulls and secondary lobes of low magnitude; thus its total noise receptivity is considerably lower.