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Old Dec 27, 2010, 02:53 AM
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BRISVEGAS BABY
Joined Mar 2010
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Patch antenna's and the Ground plane

Hi all

Does anyone know what the optimal distance is for me to mount my 900mhz patch from the ground. I have heard so far various conflicting reports including 1/2 wavelength above the ground too full wavelength. Also at such close proximity to the ground what is the optimal angle ? I see alot of people mounting their patches at about 45d egrees so as not to "waste" any of the receiving range by including the ground in the angle, but other reports indicate the the ground actualy reflects the signal and performance is best at angles at around 75degrees.

Would love some clarification on these issues.

Thanks
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Old Dec 27, 2010, 07:08 AM
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anyone
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Old Dec 27, 2010, 07:45 AM
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You have to try it out as not all areas will perform the same way.
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Old Dec 27, 2010, 07:47 AM
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United States, FL
Joined Oct 2005
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I have a dual patch setup - they are mounted at a 45 to each other - and point about 35 to 45 in the sky. The center of the patches are less than 12" off of the ground.

I'm not sure if this is ideal - but it works for me.
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Old Dec 27, 2010, 07:49 AM
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I have no A/V drop outs and excellent Picture +- 40cm from the ground, try different heights and see what the best for you is
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Old Dec 27, 2010, 07:54 AM
Honey Badger
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United States, FL
Joined Oct 2005
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I have about 8' of cable to get the patches away from everything and about 8 feet or so of feed cable to the goggles (or TV).


I built a wood bracket that velcro's to the tripod - the parches attach at 40 degrees - again - by velcro. The dual recievers are mounted on the back. The bracket that the patches mount to is hinged - that way I can change the altitude which they are pointing. The only thing that I would consider changing is adapting the bracket so I can change the altitude of each patch independently of each other.




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Old Dec 27, 2010, 08:08 AM
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BRISVEGAS BABY
Joined Mar 2010
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ok so the general idea im getting is trial an error is the way to go. But i am seeing that most of everyone has there patch pretty close to the ground... has anyone had better results with thier patch on an tripod (4-6 feet) from the ground.

also any opinions on the angle from the ground. I do not mind if it is personal expereince or a scientific model.

Cheers
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Old Dec 27, 2010, 08:24 AM
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Amherst, VA
Joined Jun 2006
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Patches are ground plane dependant. I mount mine between 4 and 6" off the ground for best results.
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Old Dec 27, 2010, 08:38 AM
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BRISVEGAS BABY
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Quote:
Originally Posted by IBCrazy View Post
Patches are ground plane dependant. I mount mine between 4 and 6" off the ground for best results.

thankyou, what is your opinion regarding the angle of the patch from the ground. (if it matters i do everything from fast flying (100-150km/h) close to the gound to high altitude slow flying)
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Old Dec 27, 2010, 08:39 AM
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BRISVEGAS BABY
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also regarding the measurements are the from the center of the patch or from the bottom.

thanks again
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Old Dec 27, 2010, 08:55 AM
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4-6" from the bottom of the patch and angled 30 degrees seems optimal.
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Old Dec 27, 2010, 09:18 AM
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BRISVEGAS BABY
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thanks everyone for your help.... this info fits well with my plans for my new ground station. thanks again.

cheers
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Old Feb 19, 2011, 03:52 AM
VaZ
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IBCrazy, it's true that yagis do not have this kind of issues?
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