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Question: two yagi


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hello

I intend to use two yagi 16 or 19 dbi in parallel with a EZtrack and RX Diversity for long distance flight.

One with Vertical polarization and the other, Horizontal polarization.

What is the distance required between the two antenna in parallel ?

Thank you for your support technical

jdm66

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With one Vertical and the other Horizontal there should be very little effect between them but I would go for one wavelength minimum and see how it goes.

Terry

Edited by Terry
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The greater the distance between linear aerials the better, but at least one wavelength at the operating frequency is the minimum recommended as already said.

Another solution is crossed yagis on one boom. Fed in the correct phase you will have circular polarisation with high gain.

Nigel.

Edited by Devonian
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Another solution is crossed yagis on one boom. Fed in the correct phase you will have circular polarisation with high gain.

That reminds me, there's a very nice DiY article for a 70cm and 2m circular Yagi in the May 2010 QST magazine. It's on my list of things to adapt for 900MHz (33cm) and try out.

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I used to run a 2 metre (144MHz) 10 ele crossed yagi - not many were running circular polaristation 25+ years ago, so it was mostly switched either vertical or horizontal.

It fell apart after a few years and swapped to a 4 ele quad - that lasted for many years.

Nigel.

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With one Vertical and the other Horizontal there should be very little effect between them but I would go for one wavelength minimum and see how it goes.

Terry

Hi

thank you for the answers

Can you tell me the distance in cm at 2,450 Ghz, please?

thank you

jdm66

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Approx 12.5 centimetres (5 inches) is a full wavelength at 2.4GHz.

So, anything larger than this distance will be good.

To calculate length, it's the speed of light divided by frequency in Megahertz gives length in metres.

I calculate it like this... 300/2400 = 0.125 (or more accurately 300/2450 = 0.1224489 metres).

Nigel.

Edited by Devonian
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Another solution is crossed yagis on one boom. Fed in the correct phase you will have circular polarisation with high gain.

Nigel.

Hi

thank you again for the answers

where can I find this type of antenna: (crossed yagis on one boom)?

jdm66

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I think you would have to make it yourself as I haven't seen any commercial ones.

Some ideas...

Buy 2 commercial linear ones, and then transfer all elements from one onto the boom of the other.

http://www.qsl.net/dk7zb/Cross-Yagi/crossyagi.htm

http://sv1bsx.50webs.com/antenna-pol/polarization.html

What ever you do, have fun doing it !

Nigel.

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