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Topic: Radio propagation

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In the News (Mon 21 Jan 19)

  Radio propagation - Wikipedia, the free encyclopedia
Radio propagation is a term used to explain how radio waves behave when they are transmitted, or are propagated from one point on the Earth to another.
High frequency propagation on Earth is not only affected by the inverse-square model, but by a number of other factors determined by its path from point to point.
Skywave propagation, also referred to as skip, is any of the modes that rely on refraction of radio waves in the ionosphere, which is made up of one or more ionized layers in the upper atmosphere.
en.wikipedia.org /wiki/Radio_propagation   (981 words)

For successful radio communications, it is desirable to have a good understanding of the characteristics of radio waves and how they are influenced by solar and geomagnetic fields as they travel through the earth's atmosphere.
Radio communications is effected by the variable conditions that exist in the earth's atmosphere, and this can be divided into three main regions.
The amount by which a radio wave is reflected and bounced, depends on the intensity of the ionization and also the wavelength or frequency used.
www.geocities.com /cq43ax101/Propagation.html   (1313 words)

 Ionospheric Radio Signal Propagation
The way in which radio signals travel is of great interest when planning a radio network, predicting the propagation conditions or setting up any radio system.
Radio signals in the medium and short wave bands travel by two basic means.
The D layer attenuates signals because the radio signals cause the free electrons in the layer to vibrate.
www.radio-electronics.com /info/propagation/HF/ionoprop.htm   (1454 words)

 An Introduction to Radio Propagation
This is a radio frequency propagation calculator for the transmission path between an RF transmitter and a receiver.
The parameters are displayed against a bitmap of radio stations and a hill to visually aid entry of the various parameters.
Radio Frequency Principles and Applications : The Generation, Propagation, and Reception of Signals and Noise (IEEE Press/Chapman and Hall Publishers), by Albert A. Smith, Jr.
www.sss-mag.com /prop.html   (996 words)

 Ham Radio Propagation Introduction
Ham Radio operators, shortwave radio enthusiasts often talk about propagation index numbers, the status of the solar cycle and geomagnetic conditions.
On many ham radio frequencies, especially on HF, these factors determine whether worldwide contacts can be made with very little effort (low power and a modest antenna) or radio flout conditions exist (no contacts possible).
Radio Blackouts are determined by the x-ray level measured by the primary GOES satellite.
www.n0hr.com /radio_propagation.htm   (934 words)

 Basics of Radio Wave Propagation
For propagation along the direction of the magnetic field, it is the mode in which the electric vector rotates in the same sense that an electron gyrates freely about the field.
For propagation along the direction of the magnetic field, it is the mode in which the electric vector rotates opposite to the direction of an electron gyrating freely about the field.
Describing a degraded condition of radio propagation characterized by a rapid variation in amplitude and/or phase of a radio signal (usually on a satellite communication link) caused by abrupt variations in electron density anywhere along the signal path.
ecjones.org /propag.html   (16958 words)

 The radio propagation   (Site not responding. Last check: 2007-10-22)
Radio frequencies are ranging from a few hertz, wavelengths of several thousands of km from peak-to-peak for brain waves, subsonic and oscillating at less than one cycle per second, to several thousands of gigahertz, wavelengths of a few mm from peak-to-peak for microwaves.
In this way of propagation antennas must display a very low angle of emission in order that all the power is radiated in direction of the horizon instead of escaping in the sky.
This way of propagation is sometimes welcome to work with an ham satellite in polar orbit or with ISS which signals pass through ionospheric layers.
www.astrosurf.com /lombry/qsl-propa.htm   (2921 words)

 The radio propagation
From the state of F2-layer depends the propagation between wavelengths of 100 - 10 m with an excellent reflection of signals in the 80 m band, favorable to DX in winter.
Among the side effects, due to their fast evolution, propagation is often sensible to fading (QSB) and phase shifting, giving to the modulation a highly recognizable profile that sounds like "bubbling" or "underwater" modulation in the 10 m band.
Most of these radio waves are scattered at the E-level and can be used on frequencies from 6 m to 60 cm but also in the HF band of 10 m.
www.astrosurf.org /lombry/qsl-propa5.htm   (1810 words)

 KN4LF 160 Meter Radio Propagation Theory Notes
We also have a segment in our radio service that is basically disinterested in radio propagation and don't feel it necessary to understand it in order to successfully work DX, which is certainly okay.
It is a period of increased MF radio wave absorption at high and mid latitudes occurring in mid winter and is associated with sudden stratospheric warming and the Quasi Biennial Oscillation (QBO).
The main reason that MF radio propagation "seems to be better" at the bottom of a sunspot cycle is not so much due to lower solar flux levels BUT due to much less geomagnetic activity.
www.kn4lf.com /kn4lf8.htm   (7678 words)

 Near-Real-Time MUF Map
Radio signals passing through these auroral zones will experience increased signal degradation in the form of fading, multipathing and absorption.
The radio auroral zones are typically displaced equatorward from the optical auroral zones (or the regions where visible auroral activity can be seen with the eye).
The great-circle signal path from the Eastern United States to Tokyo Japan is shown along with the distance of the path (in km) and the great-circle bearing from the U.S. to Tokyo (in degrees from north).
www.spacew.com /www/realtime.php   (743 words)

 The radio propagation
This mode of propagation is fantastic when tropospheric bending extends the range of stations well beyond their normal limit, but disadvantage, when the "Hepburn's Bending Index" is high ducting can cause unwanted interference from distant radio or TV stations too !
Usual the maximum distance of radio communications are limited by the Earth curvature and propagation conditions in the atmosphere or the ionosphere.
Radio amateurs are using OSCAR satellites (Orbiting Satellite Carrying Amateur Radio), most orbiting at high altitudes between 400 and 1500 km above ground (Phase III) and soon on the geostationary orbit (Phase IV).
www.astrosurf.org /lombry/qsl-propa6.htm   (2912 words)

 Simon Collings - Principles of Radio Propagation   (Site not responding. Last check: 2007-10-22)
Radio waves are a form of electromagnetic radiation which lies at the bottom end of the spectrum below visible light.
Specialist receivers and aerial systems are needed for the extreme limits of the radio spectrum; issues raised by this kind of operation will not be explored here.
The type of propagation that can be supported depends on the frequency and other circumstances.
scnt01426.pwp.blueyonder.co.uk /Articles/Propagation/Propagation.htm   (289 words)

 DF5AI.NET - Amateur Radio Propagation Studies
Reading the bulletins and magazines of official ham radio organizations, I often fear to be locked in a reservation of people dealing with a strange type of hobby; for an unknown reason, official ham radio organizations have dificulties to think out of the box.
We have speculated on the dx event's geophysical nature because the findings may be interpreted by double-hop sporadic E propagation and, perhaps, by tropospheric dx propagation too.
Sky Wave studies shortwave radio propagation by analysing dx reports from radio amateurs around the world, the project's details have been presented even on scientific conferences, e.g.
www.df5ai.net   (2019 words)

 Propagation prediction : Software: Propagation
Radio Propagation & Diffraction Calculator - This is a radio frequency propagation calculator for the transmission path between an RF transmitter and a receiver.
DXProp - DXprop is a radiowave propagation forecast freeware for ham radio operators, permits to predict propagation on 12 frequencies.
Analyses the audio signals from your radio, which is tuned to the NCDXF IARU HF beacon network and shows you the signal strength received from each of the 18 beacon transmitters as a plot of frequency spectrum against time.
www.dxzone.com /catalog/Software/Propagation   (1127 words)

 [No title]
Multipath propagation leads to rapid fluctuations of the phase and amplitude of the signal if the vehicle moves over a distance in the order of a wave length or more.
For propagation distances d much larger than the square of the antenna size divided by the wavelength, the far-field of the generated electromagnetic wave dominates all other components (in the far-field region the electric and magnetic fields vary inversely with distance).
The micro-cellular propagation channel typically is Rician : it contains a dominant direct component, with an amplitude determined by path loss, a set of early reflected waves adding (possibly distructively) with the dominant wave, and intersymbol interference caused by the excessively delayed waves, adding incoherently with the dominant wave.
people.deas.harvard.edu /~jones/es151/prop_models/propagation.html   (8878 words)

 Ionospheric Physics of Radio Wave Propagation
This page is dedicated to providing a simplified overview for some of the important ionosphere mechanics used in propagation research as well as discussing limitations due to the complex dynamics of the ionosphere.
Because the physics of ionospheric radio wave propagation is an extremely vast and complex topic, to describe the physics of ionospheric radio wave refraction in a short and concise manner without overwhealming the reader requires that certain assumptions be made.
The propagation of HF radio waves off the ionosphere is explicable in terms of these ideas, but the presence of several layers of plasma with densities and relative positions varying with height and time makes this problem considerably more complicated than this simplified model implies.
ecjones.org /physics.html   (1902 words)

 DX Toolbox - Shortwave / Ham Radio / HF Radio Propagation Tool
Radio propagation between locations within the grayline region of the world is often greatly enhanced.
These beacons are run by ham radio operators around the world, and can be used to determine radio propagation conditions between your location and that part of the world.
Radio propagation conditions can also be estimated between two points on the Earth.
www.blackcatsystems.com /software/dxtoolbox.html   (525 words)

 Radio Propagation Information Index
The current position of the Sun over the Earth is a primary factor determining current radio propagation conditions...
Run these radio propagation programs from the web or download and run them from your hard drive without charge.
When there are two radio antennas located on or near the Earth's surface propagation can ordinarily occur between them by groundwave.
www.smeter.net /propagation/propagation.php   (480 words)

 Radio wave propagation
List the components of a radio wave and define the terms cycle, frequency, harmonics, period, wavelength, and velocity as applied to radio wave propagation.
State how radio waves are polarized, vertically and horizontally.
The way energy is propagated into free space is a source of great dispute among people concerned with it.
www.tpub.com /neets/book10/40.htm   (1604 words)

 ARRLWeb: Propagation
Radio waves, like light waves and all other forms of electromagnetic radiation, normally travel in straight lines.
How radio waves propagate in other than straight-line paths is a complicated subject, but one that need not be a mystery.
More detailed discussions and the underlying mathematics of radio propagation physics can be found in the references listed under additional resources.
www.arrl.org /tis/info/propagation.html   (1450 words)

 Hf radio propagation - Introduction to HF Radio Propagation   (Site not responding. Last check: 2007-10-22)
Hf radio propagation - Introduction to HF Radio Propagation
HF Radio Propagation PageĀ… Monday February 28th 2005, 5:02 pm Filed under: Ham Radio.
High frequency (HF) radio frequencies are between 3 and 30 MHz.
linksseek.com /lksk/hf-radio-propagation.html   (365 words)

 Propagation Studies Committee of the Radio Society of Great Britain
To promote and encourage research by amateurs and listeners into radio propagation, whether to expand their own understanding or to publish the results to the amateur community or, even more desirably, a wider professional audience.
The current problem was a lack of propagation on the 6 and 10m bands and the consequent difficulty in finding interesting topics for discussion.
A monthly report on 28 and 50MHz propagation sponsored by the Propagation Studies Committee.Its purpose is to report, analyse and discuss propagation on the 28 and 50MHz bands and its relationship to solar-geophysical events.
www.keele.ac.uk /depts/por/psc.htm   (7111 words)

 The BeamFinder radio propagation analysis software
BeamFinder is a software tool designed to conduct analyses for radio amateurs interested in radio propagation studies.
This type of "problem" also occured in the May 20, 2003 analysis resulting in a second paper which deals with predictions on double hop sporadic E propagation on very high frequencies.
Surprisingly, this is no prediction at all because this type of very long distance propagation was indeed reported in recent years - it was actually reported more than once, in fact.
www.beamfinder.net   (629 words)

 [No title]
The equipment is relatively inexpensive and unless you use commercial radio station services to connect into the terrestrial phone system there are no phone bills to pay.
All in all, predicting the optimum frequency to use for a particular radio path is a complex task and a rather inexact science.
The Radio Telephone (Rad-Phone) service is great for keeping up with business or social contacts while you are at sea but can be frustrating if radio conditions are not up to scratch.
www.pangolin.co.nz /hf-prop/hf-prop.php   (557 words)

 HF (high frequency) and VHF Radiowave Propagation Center: Live propagation and space weather data and forecasts
It is a "must read" for Radio Amateurs, Shortwave Listeners, and radio communicators of any type who need to make the most productive use of the radio spectrum, regardless of the time of day, the season of the year, or the state of the sunspot cycle.
For more than a half-century, CQ has been on ham radio's leading edge -- the first to promote mobile operating (in the 1950s), semiconductors (in the 1960s) and packet radio -- the original e-mail (in the 1980s).
In fact, it's the most comprehensive radio hobby magazine in the U.S. Packed with up-to-date information concisely written by the top writers in the field, Monitoring Times® is your foremost guide to profiles of broadcasting and communications installations; home projects; and tips on monitoring everything from air, sea, and space to distant ports of call.
hfradio.org /propagation.html   (1521 words)

 ARRLWeb: QST Propagation Charts
ARRL Amateur Radio Map of North America -- Large, colorful wall map features current geographic detail and labels, grid squares, call sign prefixes, boundaries and more.
Propagation charts are no longer printed in QST.
Copyright © 2006, American Radio Relay League, Inc. All Rights Reserved.
www.arrl.org /qst/propcharts   (256 words)

Australia's IPS Radio and Space Services provides a nicely organized overview of HF radio propagation theory.
Propagation Service Center - dedicated to long and short term predictions on radio propagation, solar and terrestrial activity.
Realtime Propagation Monitor By LA7SL, shows important solar, ionospheric, and geomagnetic information useful in calculating and predicting present and near future radio-propagation.
members.fortunecity.com /xe1bef/propagation.htm   (1302 words)

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