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Old October 20th 05, 11:17 AM
oldcrow
 
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Default Antenna problem

Hi!

If I was to take yagi antenna for 1.2 gHz and then double the length of
each element. Would that work on 2.4 gHz?

Bob

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Old October 20th 05, 12:29 PM
HankG
 
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Default Antenna problem


"oldcrow" wrote in message
oups.com...
Hi!

If I was to take yagi antenna for 1.2 gHz and then double the length of
each element. Would that work on 2.4 gHz?


Newbie here. Doesn't higher frequency = shorter wavelength? Therefore,
shorter elements? Also, probably need to adjust spacing of elements per the
formula.

HankG


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Old October 20th 05, 12:38 PM
F8BOE
 
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Default Antenna problem

Hello,

Be careful! Thin Ice!

try it with: wavelength_in_meter = 300 / frequency_in_MHz

or go to your local phone shop and by a WLAN antenna.

73 de F8BOE Olivier ...-.-


oldcrow trolled:

Hi!

If I was to take yagi antenna for 1.2 gHz and then double the length of
each element. Would that work on 2.4 gHz?

Bob


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Old October 20th 05, 01:54 PM
Cecil Moore
 
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Default Antenna problem

oldcrow wrote:
If I was to take yagi antenna for 1.2 gHz and then double the length of
each element. Would that work on 2.4 gHz?


Cut all 1.2 gHz dimensions in half for 2.4 gHz.
--
73, Cecil http://www.qsl.net/w5dxp
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Old October 20th 05, 02:23 PM
Roy Lewallen
 
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No.

If you begin with a Yagi antenna made for exactly 1.2 GHz and *reduce*
the element length, element diameter, and element spacing all by a
factor of two, it would work at exactly 2.4 GHz. That's assuming that
the effect of the boom is negligible. If the boom is large enough to
have an effect (typically the case), you'll also have to reduce the
diameter of the boom by a factor of two.

There's an infinite number of other combinations which will work; for
example, you can leave the element and boom diameters the same and
change only the spacing and element length. But then the spacing and
element length will need to be changed by some factor other than two,
and there's no simple way to calculate the factor.

Roy Lewallen, W7EL

oldcrow wrote:
Hi!

If I was to take yagi antenna for 1.2 gHz and then double the length of
each element. Would that work on 2.4 gHz?

Bob



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Old October 20th 05, 02:23 PM
Amos Keag
 
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Default Antenna problem

No!

A Yagi is a moderately complex design. Generally a computer, or computer
generated graphics and length tables are used for element length,
spacing and boom length.

A 2.4 GHz Yagi would be close to 1/2 size, in all dimensions, of a 1.2
GHz antenna.

Your best bet is to buy a commercial antenna for your application.

AK

oldcrow wrote:

Hi!

If I was to take yagi antenna for 1.2 gHz and then double the length of
each element. Would that work on 2.4 gHz?

Bob


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Old October 20th 05, 03:10 PM
Rus
 
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Default Antenna problem

Remember that the relationship between wavelength and Frequency is
defined by the equation ---

c = Lambda X Nu

where
c = 300,000,000 meters per second
Lambda = wavelength (in meters)
Nu = Frequency in cycles per second

Thus solving for either lambda or nu reveals an inversely proportional
relationship between the two.

Consequently as the number of cycles per second (frequency) increases,
the wavelength shortens.

Rus

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Old October 20th 05, 08:31 PM
RST Engineering
 
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Default Antenna problem

No. It would work at 600 MHz.. You went the wrong way.

If you cut ALL dimensions in half it would work at 2.4 GHz.. However, ALL
dimensions include element diameters, boom diameters, element lengths and
spacing.

Jim



"oldcrow" wrote in message
oups.com...
Hi!

If I was to take yagi antenna for 1.2 gHz and then double the length of
each element. Would that work on 2.4 gHz?

Bob



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Old October 20th 05, 11:56 PM
oldcrow
 
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Default Antenna problem


oldcrow wrote:
Hi!

If I was to take yagi antenna for 1.2 gHz and then double the length of
each element. Would that work on 2.4 gHz?

Bob


Hi Guys:

Thanks for the information. I went the wrong way. I meant I have a 2.4
gHz antenna and want to revamp it for 1.2 gHz operation. Frequency
increases element length decreases. Many thanks for the input.

Bob
K2HML

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Old October 21st 05, 12:09 PM
Scott
 
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Default Antenna problem

It might work better if you HALVE the size. As freq. goes up, size of
elements goes down.

Scott
N0EDV

oldcrow wrote:

Hi!

If I was to take yagi antenna for 1.2 gHz and then double the length of
each element. Would that work on 2.4 gHz?

Bob

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