Loop antenna - Revision history

Ki7z: /* Large Loops */

2012-11-30T20:52:22Z

Large Loops

← Older revision		Revision as of 13:52, 30 November 2012
Line 17:		Line 17:
	Large loop antennas have a perimeter of at least 1/2 λ, but they develop significant gain when increased to 1 λ or 2 λ. Large loops are normally mounted in the horizontal plane.		Large loop antennas have a perimeter of at least 1/2 λ, but they develop significant gain when increased to 1 λ or 2 λ. Large loops are normally mounted in the horizontal plane.

	~~'''Need to insert diagram of large horizontal loop fed by ladder-line'''~~		[[File:skyburner.png]]

	== Quads ==		== Quads ==

G4juv at 11:15, 30 January 2012

2012-01-30T11:15:30Z

← Older revision		Revision as of 04:15, 30 January 2012
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	[[Mobile antenna\|Short linear antennas]], whether horizontal or vertical, have capacitive reactance and require an inductor for tuning. [[Small tuned loop\|small loops]] are just they opposite; they have significant inductive reactance, and require a capacitor for tuning. Most [[Small tuned loop\|small loops]] use a variable capacitor, allowing the antenna to be tuned over a wide range (5 MHz - 15 MHz is easily accomplished).		[[Mobile antenna\|Short linear antennas]], whether horizontal or vertical, have capacitive reactance and require an inductor for tuning. [[Small tuned loop\|small loops]] are just they opposite; they have significant inductive reactance, and require a capacitor for tuning. Most [[Small tuned loop\|small loops]] use a variable capacitor, allowing the antenna to be tuned over a wide range (5 MHz - 15 MHz is easily accomplished).

	Small loop antennas have a perimeter of no more than 0.12 ~~<math>\~~lambda~~</math>~~. (Remember that ~~<math>\~~lambda~~</math>~~ is the symbol for [[Electromagnetic Waves\|wavelength]].) They are normally mounted in the vertical plane.		Small loop antennas have a perimeter of no more than 0.12 λ. (Remember that λ is the symbol for [[Electromagnetic Waves\|wavelength]].) They are normally mounted in the vertical plane.

	This type of antenna has very sharp [[nulls]] at right angles to the plane of the loop. These nulls can be very useful for suppressing [[QRM]] from a local source. Simply rotate the loop until the interference can no longer be heard. Because the [[nulls]] are sharp, small changes in antenna orientation can make a large change in signal or noise received from the direction of the [[nulls]]. The [[nulls]] are sharpest on the smallest loops (perimeter approximately 0.05 ~~<math>\~~lambda~~</math>~~, and gradually broaden as the perimeter increases to 0.1 ~~<math>\~~lambda~~</math>~~ and beyond.		This type of antenna has very sharp [[nulls]] at right angles to the plane of the loop. These nulls can be very useful for suppressing [[QRM]] from a local source. Simply rotate the loop until the interference can no longer be heard. Because the [[nulls]] are sharp, small changes in antenna orientation can make a large change in signal or noise received from the direction of the [[nulls]]. The [[nulls]] are sharpest on the smallest loops (perimeter approximately 0.05 λ, and gradually broaden as the perimeter increases to 0.1 λ and beyond.

	== Large Loops ==		== Large Loops ==

	Large loop antennas have a perimeter of at least 1/2 ~~<math>\~~lambda~~</math>~~, but they develop significant gain when increased to 1 ~~<math>\~~lambda~~</math>~~ or 2 ~~<math>\~~lambda~~</math>~~. Large loops are normally mounted in the horizontal plane.		Large loop antennas have a perimeter of at least 1/2 λ, but they develop significant gain when increased to 1 λ or 2 λ. Large loops are normally mounted in the horizontal plane.

	'''Need to insert diagram of large horizontal loop fed by ladder-line'''		'''Need to insert diagram of large horizontal loop fed by ladder-line'''

TheAnarcat: move antenna designs to the small tune loop entry

2010-11-09T05:59:47Z

move antenna designs to the small tune loop entry

← Older revision		Revision as of 22:59, 8 November 2010
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	== Small Loops ==		== Small Loops ==

			''Main article: [[small tuned loop]]''

	A common saying in antenna design circles is "small, efficient, [[broadband]]: pick any two". As their name implies, small loops are small and reasonably efficient, but they are necessarily narrowband antennas. This means that even small changes in frequency require retuning the antenna.		A common saying in antenna design circles is "small, efficient, [[broadband]]: pick any two". As their name implies, small loops are small and reasonably efficient, but they are necessarily narrowband antennas. This means that even small changes in frequency require retuning the antenna.

	~~'''Need to insert diagram of a small tuned loop fed by an electrically-isolated smaller loop, like the one described [http://www.kr1st.com/swlloop.htm here].'''~~

	[[Mobile antenna\|Short linear antennas]], whether horizontal or vertical, have capacitive reactance and require an inductor for tuning. [[Small tuned loop\|small loops]] are just they opposite; they have significant inductive reactance, and require a capacitor for tuning. Most [[Small tuned loop\|small loops]] use a variable capacitor, allowing the antenna to be tuned over a wide range (5 MHz - 15 MHz is easily accomplished).		[[Mobile antenna\|Short linear antennas]], whether horizontal or vertical, have capacitive reactance and require an inductor for tuning. [[Small tuned loop\|small loops]] are just they opposite; they have significant inductive reactance, and require a capacitor for tuning. Most [[Small tuned loop\|small loops]] use a variable capacitor, allowing the antenna to be tuned over a wide range (5 MHz - 15 MHz is easily accomplished).
Line 12:		Line 12:

	This type of antenna has very sharp [[nulls]] at right angles to the plane of the loop. These nulls can be very useful for suppressing [[QRM]] from a local source. Simply rotate the loop until the interference can no longer be heard. Because the [[nulls]] are sharp, small changes in antenna orientation can make a large change in signal or noise received from the direction of the [[nulls]]. The [[nulls]] are sharpest on the smallest loops (perimeter approximately 0.05 <math>\lambda</math>, and gradually broaden as the perimeter increases to 0.1 <math>\lambda</math> and beyond.		This type of antenna has very sharp [[nulls]] at right angles to the plane of the loop. These nulls can be very useful for suppressing [[QRM]] from a local source. Simply rotate the loop until the interference can no longer be heard. Because the [[nulls]] are sharp, small changes in antenna orientation can make a large change in signal or noise received from the direction of the [[nulls]]. The [[nulls]] are sharpest on the smallest loops (perimeter approximately 0.05 <math>\lambda</math>, and gradually broaden as the perimeter increases to 0.1 <math>\lambda</math> and beyond.

	~~[http://www.kr1st.com/swlloop.htm A small receiving loop with a good frequency range]<br>~~
	~~[http://www.kr1st.com/magloop.htm A small transmitting loop]~~

	== Large Loops ==		== Large Loops ==

TimVK4YEH: /* Small Loops */

2009-05-15T00:29:52Z

Small Loops

← Older revision		Revision as of 17:29, 14 May 2009
Line 9:		Line 9:
	[[Mobile antenna\|Short linear antennas]], whether horizontal or vertical, have capacitive reactance and require an inductor for tuning. [[Small tuned loop\|small loops]] are just they opposite; they have significant inductive reactance, and require a capacitor for tuning. Most [[Small tuned loop\|small loops]] use a variable capacitor, allowing the antenna to be tuned over a wide range (5 MHz - 15 MHz is easily accomplished).		[[Mobile antenna\|Short linear antennas]], whether horizontal or vertical, have capacitive reactance and require an inductor for tuning. [[Small tuned loop\|small loops]] are just they opposite; they have significant inductive reactance, and require a capacitor for tuning. Most [[Small tuned loop\|small loops]] use a variable capacitor, allowing the antenna to be tuned over a wide range (5 MHz - 15 MHz is easily accomplished).

	Small loop antennas have a perimeter of no more than 0.12 <math>\lambda</math>. (Remember that <math>\lambda</math> is the symbol for [[wavelength]].) They are normally mounted in the vertical plane.		Small loop antennas have a perimeter of no more than 0.12 <math>\lambda</math>. (Remember that <math>\lambda</math> is the symbol for [[Electromagnetic Waves\|wavelength]].) They are normally mounted in the vertical plane.

	This type of antenna has very sharp [[nulls]] at right angles to the plane of the loop. These nulls can be very useful for suppressing [[QRM]] from a local source. Simply rotate the loop until the interference can no longer be heard. Because the [[nulls]] are sharp, small changes in antenna orientation can make a large change in signal or noise received from the direction of the [[nulls]]. The [[nulls]] are sharpest on the smallest loops (perimeter approximately 0.05 <math>\lambda</math>, and gradually broaden as the perimeter increases to 0.1 <math>\lambda</math> and beyond.		This type of antenna has very sharp [[nulls]] at right angles to the plane of the loop. These nulls can be very useful for suppressing [[QRM]] from a local source. Simply rotate the loop until the interference can no longer be heard. Because the [[nulls]] are sharp, small changes in antenna orientation can make a large change in signal or noise received from the direction of the [[nulls]]. The [[nulls]] are sharpest on the smallest loops (perimeter approximately 0.05 <math>\lambda</math>, and gradually broaden as the perimeter increases to 0.1 <math>\lambda</math> and beyond.

TimVK4YEH: /* Small Loops */

2009-05-15T00:25:43Z

Small Loops

← Older revision		Revision as of 17:25, 14 May 2009
Line 7:		Line 7:
	'''Need to insert diagram of a small tuned loop fed by an electrically-isolated smaller loop, like the one described [http://www.kr1st.com/swlloop.htm here].'''		'''Need to insert diagram of a small tuned loop fed by an electrically-isolated smaller loop, like the one described [http://www.kr1st.com/swlloop.htm here].'''

	[[Mobile antenna\|Short linear antennas]], whether horizontal or vertical, have capacitive reactance and require an inductor for tuning. Small loops are just they opposite; they have significant inductive reactance, and require a capacitor for tuning. Most small loops use a variable capacitor, allowing the antenna to be tuned over a wide range (5 MHz - 15 MHz is easily accomplished).		[[Mobile antenna\|Short linear antennas]], whether horizontal or vertical, have capacitive reactance and require an inductor for tuning. [[Small tuned loop\|small loops]] are just they opposite; they have significant inductive reactance, and require a capacitor for tuning. Most [[Small tuned loop\|small loops]] use a variable capacitor, allowing the antenna to be tuned over a wide range (5 MHz - 15 MHz is easily accomplished).

	Small loop antennas have a perimeter of no more than 0.12 <math>\lambda</math>. (Remember that <math>\lambda</math> is the symbol for [[wavelength]].) They are normally mounted in the vertical plane.		Small loop antennas have a perimeter of no more than 0.12 <math>\lambda</math>. (Remember that <math>\lambda</math> is the symbol for [[wavelength]].) They are normally mounted in the vertical plane.

Carlb: Loop Antenna moved to Loop antenna

2009-04-11T00:38:50Z

Loop Antenna moved to Loop antenna

← Older revision	Revision as of 17:38, 10 April 2009
(No difference)

Carlb: /* Quads */

2009-04-09T00:55:13Z

Quads

← Older revision		Revision as of 17:55, 8 April 2009
Line 25:		Line 25:

	[[Quad antenna\|Quad antennas]] are essential multiple large loops mounted near each other, with one of them fed and the others used as [[passive elements]]. [[Quad antenna\|Quads]] can achieve significant [[gain]]. They have more theoretical gain than the commonly used [[yagi\|yagis]], but they're harder to build since they require significantly more room and are a bit more sensitive so many people just opt for building [[yagi\|yagis]] instead.		[[Quad antenna\|Quad antennas]] are essential multiple large loops mounted near each other, with one of them fed and the others used as [[passive elements]]. [[Quad antenna\|Quads]] can achieve significant [[gain]]. They have more theoretical gain than the commonly used [[yagi\|yagis]], but they're harder to build since they require significantly more room and are a bit more sensitive so many people just opt for building [[yagi\|yagis]] instead.


			{{antennas}}

Hardaker: /* Quads */ clarify gain

2008-03-30T18:42:30Z

Quads: clarify gain

← Older revision		Revision as of 11:42, 30 March 2008
Line 24:		Line 24:
	== Quads ==		== Quads ==

	[[Quad antenna\|Quad antennas]] are essential multiple large loops mounted near each other, with one of them fed and the others used as [[passive elements]]. [[Quad antenna\|Quads]] can achieve significant [[gain]]. They have more gain than the commonly used [[yagi\|yagis]]~~. But~~, they're harder to build since they require significantly more room.		[[Quad antenna\|Quad antennas]] are essential multiple large loops mounted near each other, with one of them fed and the others used as [[passive elements]]. [[Quad antenna\|Quads]] can achieve significant [[gain]]. They have more theoretical gain than the commonly used [[yagi\|yagis]], but they're harder to build since they require significantly more room and are a bit more sensitive so many people just opt for building [[yagi\|yagis]] instead.

Hardaker: /* Quads */ mention that quads are actually higher gain than yagis.

2008-03-30T14:29:09Z

Quads: mention that quads are actually higher gain than yagis.

← Older revision		Revision as of 07:29, 30 March 2008
Line 24:		Line 24:
	== Quads ==		== Quads ==

	[[Quad antenna\|Quad antennas]] are essential multiple large loops mounted near each other, with one of them fed and the others used as [[passive elements]]. [[Quad antenna\|Quads]] can achieve significant [[gain]]~~, similar to that of~~ [[yagi\|yagis]].		[[Quad antenna\|Quad antennas]] are essential multiple large loops mounted near each other, with one of them fed and the others used as [[passive elements]]. [[Quad antenna\|Quads]] can achieve significant [[gain]]. They have more gain than the commonly used [[yagi\|yagis]]. But, they're harder to build since they require significantly more room.

YL: Quick overview of loops. Badly needs images for illustration.

2008-03-29T18:59:13Z

Quick overview of loops. Badly needs images for illustration.

New page

There are two types of loop antennas: '''small loops''' and '''large loops'''. The key difference between the two is that in a small loop, the current is approximately in phase at all points around the loop, while in a large loops the phase varies at different points. The two types of antenna have very different properties and are used for different purposes.

== Small Loops ==

A common saying in antenna design circles is "small, efficient, [[broadband]]: pick any two". As their name implies, small loops are small and reasonably efficient, but they are necessarily narrowband antennas. This means that even small changes in frequency require retuning the antenna.

'''Need to insert diagram of a small tuned loop fed by an electrically-isolated smaller loop, like the one described [http://www.kr1st.com/swlloop.htm here].'''

[[Mobile antenna|Short linear antennas]], whether horizontal or vertical, have capacitive reactance and require an inductor for tuning. Small loops are just they opposite; they have significant inductive reactance, and require a capacitor for tuning. Most small loops use a variable capacitor, allowing the antenna to be tuned over a wide range (5 MHz - 15 MHz is easily accomplished).

Small loop antennas have a perimeter of no more than 0.12 <math>\lambda</math>. (Remember that <math>\lambda</math> is the symbol for [[wavelength]].) They are normally mounted in the vertical plane.

This type of antenna has very sharp [[nulls]] at right angles to the plane of the loop. These nulls can be very useful for suppressing [[QRM]] from a local source. Simply rotate the loop until the interference can no longer be heard. Because the [[nulls]] are sharp, small changes in antenna orientation can make a large change in signal or noise received from the direction of the [[nulls]]. The [[nulls]] are sharpest on the smallest loops (perimeter approximately 0.05 <math>\lambda</math>, and gradually broaden as the perimeter increases to 0.1 <math>\lambda</math> and beyond.

[http://www.kr1st.com/swlloop.htm A small receiving loop with a good frequency range]<br>
[http://www.kr1st.com/magloop.htm A small transmitting loop]

== Large Loops ==

Large loop antennas have a perimeter of at least 1/2 <math>\lambda</math>, but they develop significant gain when increased to 1 <math>\lambda</math> or 2 <math>\lambda</math>. Large loops are normally mounted in the horizontal plane.

'''Need to insert diagram of large horizontal loop fed by ladder-line'''

== Quads ==

[[Quad antenna|Quad antennas]] are essential multiple large loops mounted near each other, with one of them fed and the others used as [[passive elements]]. [[Quad antenna|Quads]] can achieve significant [[gain]], similar to that of [[yagi|yagis]].