Log Periodic (LPDA) - Revision history

Carlb: /* External Links */

2009-04-09T00:55:00Z

External Links

← Older revision		Revision as of 17:55, 8 April 2009
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	* [http://en.wikipedia.org/wiki/Log-periodic_antenna Wikipedia article]		* [http://en.wikipedia.org/wiki/Log-periodic_antenna Wikipedia article]


			{{antennas}}

2008-08-23T00:09:48Z

fixed error

2008-08-21T19:43:21Z

added related pages links

← Older revision		Revision as of 12:43, 21 August 2008
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			Related wiki pages [[Bands]], [[Propagation]], [[Antennas]], [[Gain]], [[SWR]]

	'''L'''og '''P'''eriodic '''D'''ipole '''A'''rray - (LPDA)		'''L'''og '''P'''eriodic '''D'''ipole '''A'''rray - (LPDA)

2008-08-21T19:30:24Z

Protected "Log Periodic (LPDA)" [edit=autoconfirmed:move=autoconfirmed]

← Older revision	Revision as of 12:30, 21 August 2008
(No difference)

2008-08-21T09:47:09Z

added design link to arrl antenna book

← Older revision		Revision as of 02:47, 21 August 2008
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	Optimum design of an LPDA requires <math> \tau </math> to be set in the range <math> 0.8 \leq \tau \leq 0.95 </math>		Optimum design of an LPDA requires <math> \tau </math> to be set in the range <math> 0.8 \leq \tau \leq 0.95 </math>

	maximum gain is achieved by balancing <math> \tau </math> and <math> \~~rho~~ </math>, but has been found to occur when: <math> \~~rho~~ = 0.243\tau - 0.051 </math>		maximum gain is achieved by balancing <math> \tau </math> and <math> \sigma </math>, but has been found to occur when: <math> \sigma = 0.243\tau - 0.051 </math>

			==How do I design an LPDA?==

			The [http://www.arrl.org/catalog/?category=Antennas%2C+Transmission+Lines+%26+Propagation ARRL Antenna Book] lists steps in LPDA design:


	==External Links==		==External Links==

	* [http://en.wikipedia.org/wiki/Log-periodic_antenna Wikipedia article]		* [http://en.wikipedia.org/wiki/Log-periodic_antenna Wikipedia article]

2008-08-21T09:22:52Z

← Older revision		Revision as of 02:22, 21 August 2008
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	'''L'''og '''P'''eriodic '''D'''ipole '''~~Array~~''' - (LPDA)		'''L'''og '''P'''eriodic '''D'''ipole '''A'''rray - (LPDA)

	==What is it?==		==What is it?==

2008-08-21T09:20:43Z

Why is it called Log periodic?

← Older revision		Revision as of 02:20, 21 August 2008
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	Optimum design of an LPDA requires <math> \tau </math> to be set in the range <math> 0.8 \leq \tau \leq 0.95 </math>		Optimum design of an LPDA requires <math> \tau </math> to be set in the range <math> 0.8 \leq \tau \leq 0.95 </math>

	maximum gain is achieved by balancing <math> \tau </math> and <math> \rho </math>, but has been found to occur when:		maximum gain is achieved by balancing <math> \tau </math> and <math> \rho </math>, but has been found to occur when: <math> \rho = 0.243\tau - 0.051 </math>

	<math> \rho = 0.243\tau - 0.051 </math>

	==External Links==		==External Links==

	* [http://en.wikipedia.org/wiki/Log-periodic_antenna Wikipedia article]		* [http://en.wikipedia.org/wiki/Log-periodic_antenna Wikipedia article]

2008-08-21T09:20:18Z

added some math

← Older revision		Revision as of 02:20, 21 August 2008
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	In the diagram below,		In the diagram below,

	<math> \tau = \frac {R_n+1} {R_n}= \frac {D_n+1} {D_n}\frac {L_n+1} {L_n} </math>		<math> \tau = \frac {R_n+1} {R_n}= \frac {D_n+1} {D_n}= \frac {L_n+1} {L_n} </math>

	and		and
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	[[Image:Vk4yeh_lpda-2.jpg \| 500px]]		[[Image:Vk4yeh_lpda-2.jpg \| 500px]]

			Optimum design of an LPDA requires <math> \tau </math> to be set in the range <math> 0.8 \leq \tau \leq 0.95 </math>

			maximum gain is achieved by balancing <math> \tau </math> and <math> \rho </math>, but has been found to occur when:

			<math> \rho = 0.243\tau - 0.051 </math>

	==External Links==		==External Links==

	* [http://en.wikipedia.org/wiki/Log-periodic_antenna Wikipedia article]		* [http://en.wikipedia.org/wiki/Log-periodic_antenna Wikipedia article]

2008-08-21T08:44:00Z

Why is it called Log periodic?

← Older revision		Revision as of 01:44, 21 August 2008
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	[[Image:Vk4yeh_lpda-2.jpg \| ~~600px~~]]		[[Image:Vk4yeh_lpda-2.jpg \| 500px]]

	==External Links==		==External Links==

	* [http://en.wikipedia.org/wiki/Log-periodic_antenna Wikipedia article]		* [http://en.wikipedia.org/wiki/Log-periodic_antenna Wikipedia article]

2008-08-21T08:39:41Z

Why is it called Log periodic?

← Older revision		Revision as of 01:39, 21 August 2008
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	==Why is it called Log periodic?==		==Why is it called Log periodic?==

	In this antenna the electrical properties vary ~~loGarithmically~~ with the frequency. ~~For a simple three frequency antenna for example ( see the diagram below), the resonant frequencies can be named:~~		In this antenna the electrical properties vary logarithmically with the frequency.

	~~f1, f2,~~ and f3		Two variables (selectable and adjustable by the designer) affect the electrical characteristics of the LPDA:

	~~The dipole lengths (see~~ the ~~diagram below) can be named l1, l2~~ and l3		<math> \tau </math> known as the design parameter and

	[[Image:Vk4yeh_lpda-2.jpg \| ~~300px~~]]		<math>\rho</math> known as the relative spacing constant.

			In the diagram below,

			<math> \tau = \frac {R_n+1} {R_n}= \frac {D_n+1} {D_n}\frac {L_n+1} {L_n} </math>

			and

			<math> \rho = \frac {1-\tau}{4tan\alpha} = \frac {D_n}{2L_n} </math>


			[[Image:Vk4yeh_lpda-2.jpg \| 600px]]

	==External Links==		==External Links==

	* [http://en.wikipedia.org/wiki/Log-periodic_antenna Wikipedia article]		* [http://en.wikipedia.org/wiki/Log-periodic_antenna Wikipedia article]