![]() ![]() ![]() 5 color ring resistance value online calculator.Polyester capacitor color code calculator.Working time calculation of ultracapacitor.Application and selection calculator of voltage regulator diode.Service life of lithium manganese rechargeable battery.Charging time calculation of rechargeable battery.Plate capacitance capacitance calculator.LED current limiting resistor calculation.Also the distance between elements is small – it is possible to build directional antenna with very closely spaced active small elements which fits in a small yard even for medium wave band. A very important feature of these arrays is that they are inherently wideband. The basic principle is that the signal from one of the element is delayed with delay line and subtracted from the signal from the other element. The active antennas can be combined to obtain single direction properties – the so called phased arrays. ![]() The immunity of this small antenna to a local man made noise is very good and in urban environment very often better reception can be achieved compared to larger sized antennas. It is not a surrogate antenna and in certain conditions with properly sized loops and dipoles it will fulfill the requirements of the DX-ers. This amplifier combined with an appropriate small antenna has good sensitivity and a flat frequency response in a range of almost 3 decades. This amplifier is also capable to use a novel concept – crossed parallel loops which enables to increase substantially the sensitivity of the small wideband loops. It is always an advantage to have several antennas which can be switched quickly in order to have the best receiving for the moment. Also two mutually orthogonal loops can be switched thus making possible the use of the directional properties of the loop antennas to reduce selectively the man made noise sources or interfering stations. according to his/her interests and needs. Building the appropriate small antenna is left to the user – this reduces significantly the costs and moreover – the user can build antennas with different efficiency: bigger or smaller loops, dipoles and verticals, crossed loops etc. To solve all these problems we decided to build a wideband amplifier which is able to use both electric and magnetic small antennas so that the user can choose the best antenna for his/her particular environment and propagation and to solve for himself an ongoing dispute as to which small antenna is better – the electric or the magnetic. ![]() Existence of excellent wideband software defined radios (SDR) where the natural choice is a wideband antenna. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |