Propagation - Revision history

Worldwidejoe: /* Sky wave propagation */

2013-09-10T23:06:07Z

Sky wave propagation

← Older revision		Revision as of 16:06, 10 September 2013
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	The E and F layers contain a high density of [[Wikipedia:Ions\|ionized particles]]. [[DX]] (long distance) communications are possible when radio waves are reflected off the E and F layers in the [[Wikipedia:Ionosphere\|ionosphere]]. This way radio waves can propagate all over the earth, bouncing up and down between the ground and the ionosphere. This is called a [[sky wave]]. Note that during the day, energy from the sun splits the F layer into two distinct parts known as F1 and F2.		The E and F layers contain a high density of [[Wikipedia:Ions\|ionized particles]]. [[DX]] (long distance) communications are possible when radio waves are reflected off the E and F layers in the [[Wikipedia:Ionosphere\|ionosphere]]. This way radio waves can propagate all over the earth, bouncing up and down between the ground and the ionosphere. This is called a [[sky wave]]. Note that during the day, energy from the sun splits the F layer into two distinct parts known as F1 and F2.

	Th F-layer (between 120km and 400km above earth) is contains the highest densities of ionised particles, is the most reflective of RF energy, and hence is responsible for most DX propagation of HF communications.		The F-layer (between 120km and 400km above earth) contains the highest densities of ionised particles, is the most reflective of RF energy, and hence is responsible for most DX propagation of HF communications.

	The E layer can be found between 90km and 120km above earth. Reflection of RF waves by this layer is responsible for most of the long distance propagation valued by hams. The E layer both thins out at night, and rises, again resulting in increased propagation distances. E layer propagation is most useful for frequencies below 10MHz.		The E-layer can be found between 90km and 120km above the earth. Reflection of RF waves by this layer is responsible for most of the long distance propagation valued by hams. The E layer both thins out at night, and rises, again resulting in increased propagation distances. E layer propagation is most useful for frequencies below 10MHz.

	Sporadic [[E-Skip]] is caused by "clouds" of especially intense ionisation. These are highly reflective and allow DX communication from 25MHz to 225MHZ. The clouds are usually relatively short lived, and occur mostly during summer months.		Sporadic [[E-Skip]] is caused by "clouds" of especially intense ionisation. These are highly reflective and allow DX communication from 25MHz to 225MHZ. The clouds are usually relatively short lived, and occur mostly during summer months.

Worldwidejoe: /* Sky wave propagation */

2013-09-10T23:04:03Z

Sky wave propagation

← Older revision		Revision as of 16:04, 10 September 2013
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	The E layer can be found between 90km and 120km above earth. Reflection of RF waves by this layer is responsible for most of the long distance propagation valued by hams. The E layer both thins out at night, and rises, again resulting in increased propagation distances. E layer propagation is most useful for frequencies below 10MHz.		The E layer can be found between 90km and 120km above earth. Reflection of RF waves by this layer is responsible for most of the long distance propagation valued by hams. The E layer both thins out at night, and rises, again resulting in increased propagation distances. E layer propagation is most useful for frequencies below 10MHz.

	Sporadic [[E-Skip]] is caused by "clouds" of especially intense ionisation. These are highly reflective and allow DX communication from 25MHz to 225MHZ. The ~~cluods~~ are usually relatively short lived, and occur mostly during summer months.		Sporadic [[E-Skip]] is caused by "clouds" of especially intense ionisation. These are highly reflective and allow DX communication from 25MHz to 225MHZ. The clouds are usually relatively short lived, and occur mostly during summer months.

	The D layer can be found between 50km to 90km above earth. Propagation by reflection from this layer is quite rare as it is highly absorbent of RF energy. The thickness of the D layer decreases during the night, allowing more RF to travel through to the E and F layers, hence propagation often improves during the night.		The D layer can be found between 50km to 90km above earth. Propagation by reflection from this layer is quite rare as it is highly absorbent of RF energy. The thickness of the D layer decreases during the night, allowing more RF to travel through to the E and F layers, hence propagation often improves during the night.

Gm4jjj: Added link to Moonbounce

2010-11-15T15:08:19Z

Added link to Moonbounce

← Older revision		Revision as of 08:08, 15 November 2010
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	* [[Trans-Equatorial Propagation]]		* [[Trans-Equatorial Propagation]]
	* [[Lightning scatter]]		* [[Lightning scatter]]
			* [[Moonbounce (EME)]]
	* [[Gridsquares]]		* [[Gridsquares]]
	* [[Interference]]		* [[Interference]]

TimVK4YEH: /* Day and Night Propagation */

2010-11-14T08:09:23Z

Day and Night Propagation

← Older revision		Revision as of 01:09, 14 November 2010
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	The D layer can be found between 50km to 90km above earth. Propagation by reflection from this layer is quite rare as it is highly absorbent of RF energy. The thickness of the D layer decreases during the night, allowing more RF to travel through to the E and F layers, hence propagation often improves during the night.		The D layer can be found between 50km to 90km above earth. Propagation by reflection from this layer is quite rare as it is highly absorbent of RF energy. The thickness of the D layer decreases during the night, allowing more RF to travel through to the E and F layers, hence propagation often improves during the night.

	==Day and ~~Night Propagation~~==		==Day and night ionospheric conditions==

	Ionisation of the atmosphere varies considerably between day and night. During the day:		Ionisation of the atmosphere varies considerably between day and night. During the day:

TimVK4YEH: added info and pics - needs reorganisation?

2010-11-14T07:37:22Z

added info and pics - needs reorganisation?

← Older revision		Revision as of 00:37, 14 November 2010
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	The D layer can be found between 50km to 90km above earth. Propagation by reflection from this layer is quite rare as it is highly absorbent of RF energy. The thickness of the D layer decreases during the night, allowing more RF to travel through to the E and F layers, hence propagation often improves during the night.		The D layer can be found between 50km to 90km above earth. Propagation by reflection from this layer is quite rare as it is highly absorbent of RF energy. The thickness of the D layer decreases during the night, allowing more RF to travel through to the E and F layers, hence propagation often improves during the night.

			==Day and Night Propagation==

			Ionisation of the atmosphere varies considerably between day and night. During the day:
			* the D and E layers are continuous
			* the F layer splits into F1 and F1 (F1 is lower than F2)

			During the night:
			* The F1 and F2 layers coalesce to form a single F layer that lies between the position of the daylight F1 and F2
			* the D layer disappears altogether
			* the E Layer is patchy
			[[Image:Day and night atmos.jpg \|700px]]

			These ionosperic variations are responsible for the variations in propagation noticed across a 24 hour period.

			==How are ionospheric conditions measured?==

			Ionospheric conditions are measured using an '''ionosonde.''' This has two variants:
			* a single high frequency radar that sends short pulses vertically upwards and records the time for the signals to be reflected back to the same place. Ionosondes are used to measure the height of the various ionised layers.

			[[Image:Ionosonde.jpg]]

			* pairs of transmitter and receiver that are a measured distance apart. These allow propagation between points to be measured




	== See also ==		== See also ==

TimVK4YEH: added internal link to skip zone page

2010-11-05T07:20:19Z

added internal link to skip zone page

← Older revision		Revision as of 00:20, 5 November 2010
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	== See also ==		== See also ==

			* [[Antennas]]
			* [[Aurora]]
	* [[Tropospheric ducting]]		* [[Tropospheric ducting]]
	* [[Sunspot Cycle]]		* [[Sunspot Cycle]]
	* [[Meteor scatter]]		* [[Meteor scatter]]
	* [[Aurora]]
	* [[Trans-Equatorial Propagation]]		* [[Trans-Equatorial Propagation]]
	* [[Lightning scatter]]		* [[Lightning scatter]]
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	* [[Electromagnetic Waves]]		* [[Electromagnetic Waves]]
	* [[Feedlines]]		* [[Feedlines]]
	* [[Antennas]]
	* [[What causes QRN?]]		* [[What causes QRN?]]
			* [[Skip Zone]]

	==External links==		==External links==

TimVK4YEH: added voacap link

2010-11-03T23:10:39Z

added voacap link

← Older revision		Revision as of 16:10, 3 November 2010
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	* [http://prop.hfradio.org/ Radiowave Propagation Center]		* [http://prop.hfradio.org/ Radiowave Propagation Center]
	* [http://www.swpc.noaa.gov/dregion/index.html D-Region Absorption Prediction Center]		* [http://www.swpc.noaa.gov/dregion/index.html D-Region Absorption Prediction Center]
			* [http://online.voacap.com/ Online VOACAP propagation tool]


	{{propagation}}		{{propagation}}

TheAnarcat at 16:03, 11 October 2010

2010-10-11T16:03:17Z

← Older revision		Revision as of 09:03, 11 October 2010
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	~~Wikipedia has a good article concerning~~ [[Radio ~~waves~~]] propagation, ~~see Wikipedia:Radio_propagation~~.		[[Radio wave]] propagation largely depends on atmospheric conditions, the [[band]] and [[power]] used to operate the radio equipment.

	~~{{stub}}~~		''Main article: [[Wikipedia:Radio propagation]]''

	~~== Propagation Theory ==~~		[[Ground waves]] are "line of sight" communication. Atmospheric conditions come into play when transmitting between ham radio stations that are farther away and so, because of the curvature of the earth, cannot be reached through a straight line. This is called a [[sky wave]]. Since those atmospheric conditions are ever-changing, there are resources to allow operators to predict those conditions and the idea propagation techniques to use.

	~~Radio frequencies form a fragment of~~ the ~~entire electromagnetic spectrum. It is generally considered that radio frequencies are found between 10 kHz and 300 GHz. 10 kHz is considered~~ to ~~be the lower end of the electromagnetic spectrum. Above 300 GHz infrared begins~~.		Various [[bands]] have different properties regarding those atmospheric conditions and can bound off the ionosphere or other particles to propagate further away.

	~~Electromagnetic energy travels~~ as ~~waves that move at the speed~~ of ~~light (300 000km/s~~)~~, normally in a straight line~~. ~~Atmospheric conditions can affect radio transmissions, and are responsible for transmissions between ham radio stations that are not a "line of sight" distance apart~~.		More powerful stations are going to be able to reach further than weak stations, although some ham operators take it as a challenge to reach other stations with weaker power ratings (~5W instead of 100W to sometimes 1000W). This is called [[QRP]].

	Electromagnetic waves have two components, electric and magnetic. These are at right angles to each other. Unlike sound waves, electromagnetic waves do not need a medium through which to pass. Hence radio transmissions to and from deep space are possible.		== Sky wave propagation ==

	~~DX (long distance) communications are possible when radio waves are reflected off the E and F layers in the the~~ [~~http~~:~~//en~~.~~wikipedia.org/wiki/Ionosphere ionosphere~~]~~. The E and F layers contain high electron densities which coincide with high temperatures.~~		[[Image:Vk4yeh_ionosphere.png\|300px\|right]]

	[[~~Image~~:~~Vk4yeh_ionosphere~~.~~png~~\|~~300px~~]]		The E and F layers contain a high density of [[Wikipedia:Ions\|ionized particles]]. [[DX]] (long distance) communications are possible when radio waves are reflected off the E and F layers in the [[Wikipedia:Ionosphere\|ionosphere]]. This way radio waves can propagate all over the earth, bouncing up and down between the ground and the ionosphere. This is called a [[sky wave]]. Note that during the day, energy from the sun splits the F layer into two distinct parts known as F1 and F2.

	~~The D~~ layer ~~can be found~~ between ~~50km to 90km~~ above earth~~. Propagation by reflection from this layer~~ is ~~quite rare as it~~ is ~~highly absorbent~~ of RF energy~~. The thickness of the D layer decreases during the night~~, ~~allowing more RF to travel through to the E~~ and ~~F layers,~~ hence propagation ~~often improves during the night.~~		Th F-layer (between 120km and 400km above earth) is contains the highest densities of ionised particles, is the most reflective of RF energy, and hence is responsible for most DX propagation of HF communications.

	~~[http://www.swpc.noaa~~.~~gov/dregion/index.html D-Region Absorption Prediction Center]~~

	The E layer can be found between 90km and 120km above earth. Reflection of RF waves by this layer is responsible for most of the long distance propagation valued by hams. The E layer both thins out at night, and rises, again resulting in increased propagation distances. E layer propagation is most useful for frequencies below 10MHz.		The E layer can be found between 90km and 120km above earth. Reflection of RF waves by this layer is responsible for most of the long distance propagation valued by hams. The E layer both thins out at night, and rises, again resulting in increased propagation distances. E layer propagation is most useful for frequencies below 10MHz.
Line 23:		Line 21:
	Sporadic [[E-Skip]] is caused by "clouds" of especially intense ionisation. These are highly reflective and allow DX communication from 25MHz to 225MHZ. The cluods are usually relatively short lived, and occur mostly during summer months.		Sporadic [[E-Skip]] is caused by "clouds" of especially intense ionisation. These are highly reflective and allow DX communication from 25MHz to 225MHZ. The cluods are usually relatively short lived, and occur mostly during summer months.

	~~Th F-~~layer (between ~~120km and 400km~~ above earth) is ~~contains the highest densities of ionised particles,~~ is ~~the most reflective~~ of RF energy, and hence ~~is responsible for most DX~~ propagation ~~of HF communications. During the day, energy from the sun splits~~ the ~~F layer into two distinct parts known as F1 and F2~~.		The D layer can be found between 50km to 90km above earth. Propagation by reflection from this layer is quite rare as it is highly absorbent of RF energy. The thickness of the D layer decreases during the night, allowing more RF to travel through to the E and F layers, hence propagation often improves during the night.

	~~== Propagation Prediction ==~~

	~~[[IPS\|Australian Space Weather Agency (IPS)]]~~

	~~[http://prop.hfradio.org/ Radiowave Propagation Center]~~

	== See also ==		== See also ==

	* [[Feedlines]]
	* [[Antennas]]
	* [[What causes QRN?]]
	* [[Tropospheric ducting]]		* [[Tropospheric ducting]]
	* [[Sunspot Cycle]]		* [[Sunspot Cycle]]
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	* [[Interference]]		* [[Interference]]
	* [[Electromagnetic Waves]]		* [[Electromagnetic Waves]]
			* [[Feedlines]]
			* [[Antennas]]
			* [[What causes QRN?]]

	==External links==		==External links==
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	* [http://www.hfradio.org/propagation.html Propagation Resource Center]		* [http://www.hfradio.org/propagation.html Propagation Resource Center]
	* [http://www.qsl.net/n9ssa/mpwcalc.html Miles per watt/ km per watt calculator] You will need to enter the gridsquares of two stations and the tx power of the transmitting station.		* [http://www.qsl.net/n9ssa/mpwcalc.html Miles per watt/ km per watt calculator] You will need to enter the gridsquares of two stations and the tx power of the transmitting station.
			* [[IPS\|Australian Space Weather Agency (IPS)]] - Australian prediction center
			* [http://prop.hfradio.org/ Radiowave Propagation Center]
			* [http://www.swpc.noaa.gov/dregion/index.html D-Region Absorption Prediction Center]


	{{propagation}}		{{propagation}}

TheAnarcat at 14:20, 3 October 2010

2010-10-03T14:20:37Z

← Older revision		Revision as of 07:20, 3 October 2010
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			Wikipedia has a good article concerning [[Radio waves]] propagation, see Wikipedia:Radio_propagation.

	{{stub}}		{{stub}}

TheAnarcat at 14:19, 3 October 2010

2010-10-03T14:19:44Z

@@ Line 1: / Line 1: @@
-Related wiki pages are [[Feedlines]] and [[Antennas]] [http://amateur-radio-wiki.net/index.php?title=What_causes_QRN%3F QRN], [[Tropospheric ducting]], [[Sunspot Cycle]],  [[Meteor scatter]], [[Aurora]], [[Trans-Equatorial Propagation]], [[Lightning scatter]], [[Gridsquares]], [[Interference]], [[Electromagnetic Waves]]
+{{stub}}
-== Propagation Prediction ==
+== Propagation Theory ==
 Radio frequencies form a fragment of the entire electromagnetic spectrum. It is generally considered that radio frequencies are found between 10 kHz and 300 GHz. 10 kHz is considered to be the lower end of the electromagnetic spectrum. Above 300 GHz infrared begins.
@@ Line 28: / Line 22: @@
 Th F-layer (between 120km and 400km above earth) is contains the highest densities of ionised particles, is the most reflective of RF energy, and hence is responsible for most DX propagation of HF communications.  During the day, energy from the sun splits the F layer into two distinct parts known as F1 and F2.
 ==External links==
 * [http://www.hfradio.org/propagation.html Propagation Resource Center]
 * [http://www.qsl.net/n9ssa/mpwcalc.html Miles per watt/ km per watt calculator] You will need to enter the gridsquares of two stations and the tx power of the transmitting station.
 {{propagation}}