VHF UHF Propagation - Revision history

R4002 at 19:07, 9 January 2023

2023-01-09T19:07:59Z

← Older revision		Revision as of 19:07, 9 January 2023
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	= Tropospheric scatter =		= Tropospheric scatter =
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		+	[[Category: VHF/UHF Radio Services]]

ChrisSmolinski: /* Ionospheric F2 */

2022-06-16T16:10:40Z

Ionospheric F2

← Older revision		Revision as of 16:10, 16 June 2022
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	The same mode of propagation as often occurs on HF. As intense ionization of the ionosphere's F2 layer is necessary, this mode only occurs during peak solar conditions around the maximum of the solar cycle, if at all, and only affects VHF Lo band up to perhaps the 6m band.		The same mode of propagation as often occurs on HF. As intense ionization of the ionosphere's F2 layer is necessary, this mode only occurs during peak solar conditions around the maximum of the solar cycle, if at all, and only affects VHF Lo band up to perhaps the 6m band.
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	= Ionospheric scattering =		= Ionospheric scattering =

ChrisSmolinski: /* Ionospheric scattering */

2022-06-16T16:10:17Z

Ionospheric scattering

← Older revision		Revision as of 16:10, 16 June 2022
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	= Ionospheric scattering =		= Ionospheric scattering =
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		+	This mode of VHF propagation is caused by irregularities in the D layer. It mostly affects the lower portion of VHF, below 100 MHz. Signals are typically quite weak, requiring large antennas, and the range is about 1000-2000 km.

	= Meteor Scatter =		= Meteor Scatter =

ChrisSmolinski: /* Aurora */

2022-06-16T14:31:41Z

Aurora

← Older revision		Revision as of 14:31, 16 June 2022
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	= Aurora =		= Aurora =
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		+	The E layer is ionized during auroral conditions, supporting DX on the VHF bands. However it is necessary for stations to be relatively close to the aurora, so it is most commonly used by station in northern Europe.

	= Ionospheric F2 =		= Ionospheric F2 =

ChrisSmolinski: /* Meteor Scatter */

2022-06-16T12:52:13Z

Meteor Scatter

← Older revision		Revision as of 12:52, 16 June 2022
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	= Meteor Scatter =		= Meteor Scatter =
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		+	This mode relies on ionization of the E layer by meteors entering the Earth's atmosphere. The ionization only lasts a few seconds, so very fast modes of communication (high speed CW, etc) need to be used to send messages. On the FM band, it results in brief bursts of audio. Meteor scatter is useful up to 2m band, although possible at 70 cm with high gain antennas.
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		+	Obviously it occurs more often during major meteor showers, but can happen any time of the day/year as there are typically about 5 meteors per hour even outside of meteor showers.

	= Sporadic E =		= Sporadic E =

ChrisSmolinski at 12:43, 16 June 2022

2022-06-16T12:43:45Z

← Older revision		Revision as of 12:43, 16 June 2022
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	= Trans-equatorial (TEP) =		= Trans-equatorial (TEP) =

-	This mode of propagation occurs between two locations at roughly the same distance from the magnetic equator, directly north/south of each other. See the map below for the location of the magnetic equator. It affects all VHF and UHF bands, although less often as one moves up in frequency. While TEP is fairly common on VHF-Lo and the 6 meter band worldwide, 144 MHz and higher propagation is rare outside of the Americas for unknown reasons. TEP is more common during periods of high solar activity.	+	This mode of propagation occurs between two locations at roughly the same distance from the magnetic equator, directly north/south of each other. See the map below for the location of the magnetic equator. It affects all VHF and UHF bands, although less often as one moves up in frequency. While TEP is fairly common on VHF-Lo and the 6 meter band worldwide, 144 MHz and higher propagation is rare outside of the Americas for unknown reasons. TEP is more common during periods of high solar activity. Distances vary widely, roughly 2500-9000 km.

	There are two types of TEP:		There are two types of TEP:

ChrisSmolinski at 12:42, 16 June 2022

2022-06-16T12:42:31Z

← Older revision		Revision as of 12:42, 16 June 2022
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	= Trans-equatorial (TEP) =		= Trans-equatorial (TEP) =
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		+	This mode of propagation occurs between two locations at roughly the same distance from the magnetic equator, directly north/south of each other. See the map below for the location of the magnetic equator. It affects all VHF and UHF bands, although less often as one moves up in frequency. While TEP is fairly common on VHF-Lo and the 6 meter band worldwide, 144 MHz and higher propagation is rare outside of the Americas for unknown reasons. TEP is more common during periods of high solar activity.
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		+	There are two types of TEP:
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		+	* Type I: Occurs roughly between 2-7 pm local time, and supports VHF-Lo through the 6 meter band slightly higher.
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		+	* Type II: Occurs roughly between 7-11 pm local time, supporting propagation through the 70 cm band.
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	[[File:Inclination-map.jpg]]		[[File:Inclination-map.jpg]]

ChrisSmolinski at 12:30, 16 June 2022

2022-06-16T12:30:45Z

← Older revision		Revision as of 12:30, 16 June 2022
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	= Trans-equatorial (TEP) =		= Trans-equatorial (TEP) =
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		+	[[File:Inclination-map.jpg]]
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	= Tropospheric Ducting =		= Tropospheric Ducting =

	= Tropospheric scatter =		= Tropospheric scatter =

ChrisSmolinski: Created page with "= Aurora = = Ionospheric F2 = The same mode of propagation as often occurs on HF. As intense ionization of the ionosphere's F2 layer is necessary, this mode only occurs during ..."

2022-06-16T12:02:37Z

Created page with "= Aurora = = Ionospheric F2 = The same mode of propagation as often occurs on HF. As intense ionization of the ionosphere's F2 layer is necessary, this mode only occurs during ..."

New page

= Aurora =

= Ionospheric F2 =

The same mode of propagation as often occurs on HF. As intense ionization of the ionosphere's F2 layer is necessary, this mode only occurs during peak solar conditions around the maximum of the solar cycle, if at all, and only affects VHF Lo band up to perhaps the 6m band.

= Ionospheric scattering =

= Meteor Scatter =

= Sporadic E =

= Trans-equatorial (TEP) =

= Tropospheric Ducting =

= Tropospheric scatter =