EA4FSITECHNICAL ARTICLES
Technical notes, articles and presentations on radio communications, antennas, propagation and radio direction finding.
Antenna Modelling and Simulation
¼-Wavelength Vertical Monopole for the 2 m Band
MMANA-GAL simulation of a ¼-wavelength vertical monopole designed for a centre frequency of 146 MHz. Results are presented for standing wave ratio, radiation pattern and antenna input impedance.
Notes on Antenna Simulation using NEC-2
Notes and recommendations about antenna simulations using software based on the NEC-2 algorithm, developed by the Lawrence Livermore National Laboratory. The recommendations and rules of design have been compiled both from the manuals of some programs and from technical articles about antenna simulation. Article published in the Spanish Amateur Radio Union Magazine (URE). December 2012.
Effects of Installing VHF/UHF Monopoles at Different Heights
Analysis of the effects of installation height above ground on the SWR and gain of VHF/UHF quarter-wavelength monopoles.
Ground Planes with 4 Radials for VHF/UHF Monopoles
4NEC2 analysis of a quarter-wavelength monopole with four radials arranged at 90° and 45°.
HF Propagation
Geometry and Operative Aspects of the Simple Modes of Ionospheric Propagation
Geometry of ionospheric propagation through successive hops, including radio-path length, hop distance, coverage areas, power budgets and maximum usable frequency.
NVIS Communications in the HF Band
Article about the Near Vertical Incident Skywave (NVIS) HF propagation mode, used at great length in emergency and tactical communications. The article was published in the Spanish Amateur Radio Union (URE) magazine, in november 2008.
NVIS Propagation: Study and Experiences
Transcription of the original article by the then Captain Julián Iranzo Collado of the 21st Tactical Signals Regiment of the Spanish Army, published in the "Memorial del Arma de Ingenieros" (Spanish Army Corps of Engineers Magazine), nº37, year 1989. Reproduced with permission. Available in Spanish only.
AVAILABLE IN SPANISH ONLY
NVIS Propagation Model: A Practical Case Study
Transcription of the original article by the then Captain Julián Iranzo Collado of the 21st Tactical Signals Regiment of the Spanish Army, published in the "Memorial del Arma de Ingenieros" (Spanish Army Corps of Engineers Magazine), nº39, year 1990. Reproduced with permission. Available in Spanish only.
AVAILABLE IN SPANISH ONLY
Daily Evolution of the Ionosphere
Illustrative video showing the evolution of the different layers of the ionosphere over a full day, at 15-minute intervals, using data recorded by the El Arenosillo ionospheric sounding station in Huelva (Spain), operated by the Spanish National Institute of Aerospace Technology (INTA). The data collected by the ionosonde are stored in SAO-format files and can be viewed with SAO Explorer, developed by the Center for Atmospheric Research at the University of Massachusetts Lowell.
HF Network Planning
HF Link Calculations and Predictions
HF Propagation Forecasts by EA3EPH
HF propagation calculations and forecasts prepared by Alonso Mostazo Plano (EA3EPH) using his "Sondeo" software. The bulletins are commonly issued during disaster-mitigation operations in which amateur radio operators may participate. EA3EPH has provided this bulletin service since 2010.
HF Link Calculation: W6ELProp Manual in Spanish
W6ELProp, developed by Sheldon C. Shallon (W6EL), calculates the maximum usable frequency (MUF) and optimum working frequencies for HF radio links between stations located anywhere in the world and for any time of day. A comprehensive Spanish-language manual with practical examples is provided.
AVAILABLE IN SPANISH ONLY
HF Link Calculation: PropView Manual in Spanish
Spanish-language user manual for PropView, which provides simplified HF radio-link calculations based on the IONCAP model.
AVAILABLE IN SPANISH ONLYSpace Weather
Risks derived from the Space Weather (ESP)
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. The article provides a description of the Space Weather phenomena and an analysis of the risks for people and several technological systems, among them the HF radio communication systems. The article also provides a description of the observation and early warning systems currently available in several countries.
AVAILABLE IN SPANISH ONLY
Impact of the severe Space Weather events on the terrestrial radio communication systems (ESP)
Lecture on the impact of the severe Space Weather events on the terrestrial radio communication systems, presented in the Spanish National Civil Protection School (General Directorate of Civil Protection and Emergencies, Ministry of Interior) during the "Conference on Space Weather", 23-24 March 2011. Available in Spanish only.
AVAILABLE IN SPANISH ONLYVHF/UHF Radio Coverage Calculations
Radio Mobile Coverage Calculation Manual
A comprehensive Spanish-language manual on using Radio Mobile for radio-coverage calculations, including terrain models, cartography, network configuration, coverage maps and practical applications. Available in Spanish only.
AVAILABLE IN SPANISH ONLY
ÁNCORA Project: Radio Coverage Analysis
Spanish-language project documenting the creation of a Google Earth GIS with operational information on the national REMER repeater network, including radio-coverage maps produced with Radio Mobile. Available in Spanish only.
AVAILABLE IN SPANISH ONLY
R84 Henares Repeater Coverage (URE Jarama)
Radio Mobile coverage simulation for the R84 Henares repeater, considering a typical mobile station operating in the 70 cm band.
VHF/UHF Propagation
Direction Finding
Reference
Emergency Communications
Emergency Telecommunications Glossary
A collection of definitions of terms relating to emergency telecommunications, amateur radio, civil protection and communications systems.
AVAILABLE IN SPANISH ONLY
Radiograms
A practical guide to using radiograms for reliable message handling through Amateur Radio and REMER emergency communications networks.