Differences

This shows you the differences between two versions of the page.

--- en:antennas [2019/04/17 12:18] – fluktuacia
+++ en:antennas [2019/04/21 14:49] – [Antennas for Bolidozor network] fluktuacia
@@ Line 2: / Line 2: @@
 ====== Antennas for Bolidozor network ======
-Antenna is the first signal input to a [[en:rmds|radio detection sattion]]. It is therefore necessary not to neglect its choice as a signal that is not received cannot be processed. A typical radio antenna receives not only meteor reflections, but also other radio signals - thus, the location of antenna is of high importance and should be chosen carefully. Suitable antenna characteristics can make the choice of location easier and can improve the overall antenna gain. Advantageous are following parameters:
+Antenna is the first signal input to a [[en:rmds|radio detection station]]. It is therefore necessary not to neglect its choice as a signal that is not received cannot be processed. A typical radio antenna receives not only meteor reflections, but also other radio signals - thus, the location of antenna is of high importance and should be chosen carefully. Suitable antenna characteristics can make the choice of location easier and can improve the overall antenna gain. Advantageous are the following parameters:
-  * Sensitivity in the upper hemisphere with respect to observation site.
+  * Sensitivity in the upper hemisphere with respect to an observation site.
   * High efficiency.
   * Insensitivity to signal linear polarisation angle.
-  * Suppression of unwanted signals reception from vely low elevations (usually ground noise).
+  * Suppression of unwanted signal reception from very low elevations (usually ground noise).
@@ Line 72: / Line 72: @@
 ==== Preamplifier LNA01A ====
-Good quality preamplifier is essential due to antenna's low gain and low intensities of reflected signal.
+A good quality preamplifier is essential due to loses during signal propagation via antenna and due to low intensities of reflected signal.
-[[http://www.mlab.cz/Modules/CommRF/LNA01A/LNA01A_Bottom_Small.JPG|LNA01A]] represents a preamplifier designed for meteor detection in 2m band. It amplifies the signal from antenna and thus decrease the effect of receiver's own noise. It further reduces complications connected with signal transmission via coaxial cable (it compensates for the cable attenuation and so it is possible to use cheaper coaxial cable of RG58 type).
+[[http://www.mlab.cz/Modules/CommRF/LNA01A/LNA01A_Bottom_Small.JPG|LNA01A]] is a preamplifier designed for meteor detection in 2m band. Its benefit is mainly in amplification of signal from antenna (thus decreasing the influence of antenna’s lead (?? svod antény) and the noise from receiver). Furthermore it reduces complications connected to signal radiation from receiver’s oscillator.
 {{cs:antennas:gp_plast16.jpg?direct&300 | }}
 {{cs:antennas:gp_plast17.jpg?direct&300 | }}
+Preamplifier is therefore always installed in the immediate proximity of antenna in an plastic waterproof wiring box.
-==== Further improvements ====
+==== Modelling tools ====
-Antenna should fulfil these requirements.
+  * [[http://www.qsl.net/kd2bd/splat.html|RF Signal Propagation, Loss, And Terrain analysis tool for the electromagnetic spectrum between 20 MHz and 20 GHz.]]
+  * [[http://en.wikipedia.org/wiki/Numerical_Electromagnetics_Code|NEC2 software]]
+  * [[https://github.com/BogdanDIA/nec2-array|Antenna field in v NEC2]]
-  * It should have larger gain than currently used Ground Plane.
-  * Radiation pattern should not reach zero at zenith.
-  * It should have hemispheric radiation pattern.
-  * It should be possible to integrate it with an amplifier.
-  * Radiation pattern and directionality should be made adjustable via phasing of more antennas.