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Technical articles index

01.	NVIS communications in the HF band (Nov 2008).
02.	HF radio communications glossary (Nov 2009, Spanish).
03.	Effects of the installation of VHF/UHF monopoles at different heights (Dec 2009).
04.	VHF/UHF monopole ground planes with 4 radials (Dec 2009).
05.	Daily evolution of the ionosphere (Mar 2010).
06.	Geometry and operative aspects of the simple modes of ionospheric propagation (Apr 2010).
07.	Analysis of the radio contacts between the Canary Islands and South America in the 50 MHz band in March 2010 (Apr 2010).
08.	Risks derived from the Space Weather (Nov 2010, Spanish).
09.	EA4FSI's channel on Youtube.

NVIS communications in the HF band

Description of the near vertical incident skywave (NVIS) mode of propagation in HF, which allows communications up to 300 km without shadow zones. Article published in the Spanish Amateur Radio Union Magazine.

Nov 2008.

HF radio communications glossary

A collection of terms related with radio communications in the HF band. The collection currently has 174 terms. Available in Spanish only.

Nov 2009.

Installation of VHF/UHF monopoles at different heights

Analysis of the effects derived from installing a VHF/UHF monopole at different heights over ground, made with 4NEC2. The optimal heigths are determined and also the heights to be avoided, as a function of the calculated gain taking into account the antenna, the mast and the ground plane.

Dec 2009.

VHF/UHF monopole ground planes with 4 radials

Analysis of artificial ground planes for VHF/UHF monopoles, performed with 4NEC2. Includes ground planes made of 4 radials at 90 degrees and 45 degrees.

Dec 2009.

Daily evolution of the ionosphere

Educational video about the evolution of the different layers of the ionosphere during a whole day, using scientific data from the ionospheric sounding station "El Arenosillo", located in southwestern Spain.

Mar 2010.

Geometry and operative aspects of the simple modes of ionospheric propagation

This article describes the geometry of the propagation of radio waves through several hops using one of the layers of the ionosphere, a mode commonly used in the HF bands and also in the VHF and even the UHF bands under some circumstances.

Apr 2010.

Analysis of the radio contacts between the Canary Islands and South America 2010 in the 50 MHz band in March 2010

Propagation study on the contacts made by amateur radio stations between the Canary Islands (Spain) and several countries in South America, in the 50 MHz band, between the days 17-21 March 2010.

Apr 2010.

Risks derived from the Space Weather

Report presented in November 2010 to the Spanish General Directorate of Civil Protection and Emergencies (DGPCE), on the occasion of the Technical Congress on Space Weather. Provides a description of the Space Weather phenomena and an analysis of the risks for people and several technological systems, as well as a description of the observation and early warning systems currently available in several countries. Available in Spanish only.

Nov 2010.

EA4FSI's channel on Youtube

EA4FSI-28T1 - Technical articles