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Old Mar 28, 2010, 11:03 PM
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900 mhz patch antenna help

Does anyone have the dimensions for a regular 900mhz patch antenna.I found a website that had pictures of a patch antenna for 1.2ghz that someone had opened and had taken measurements,but I need one for 900mhz.If anyone has any pictures of a 900mhz patch antenna internals with measurements like the example below please post them.
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Old Mar 29, 2010, 04:16 AM
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Here ya go...

http://www.rc-cam.com/gp_patch.htm
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Old Mar 29, 2010, 08:25 AM
ess
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is this 910mhz patch antenna suitable for 1040mhz? or 1010mhz?
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Old Mar 29, 2010, 09:02 AM
13brv3's Avatar
Navarre, FL
Joined Mar 2002
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Quote:
Originally Posted by up2late View Post
Does anyone have the dimensions for a regular 900mhz patch antenna.I found a website that had pictures of a patch antenna for 1.2ghz that someone had opened and had taken measurements,but I need one for 900mhz.If anyone has any pictures of a 900mhz patch antenna internals with measurements like the example below please post them.
I just had a 900 and 1200 patch apart a few days ago, and made note of the measurements. The two patches I have (from L-Com) are identical, with the exception of the size of the upper element, and the cable.

As shown in your picture, the right side of the upper element,and the cable attachment are in the same location. For the 900 MHz unit, the left to right measurement is 146mm, and the top to bottom is 161mm.

The cables are much different in length, and could even be different types, though that's unlikely. They do seem to be using the cables to match the overall impedance. My limited understanding is that the impedance match would be more of a problem if it were used as a transmit antenna. As you can see in the RC-CAM link, he got rid of the cable completely.

Cheers,
Rusty
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Old Mar 29, 2010, 04:41 PM
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Thank you,Rusty that is what I am looking for.If you have time could you find the measurement for the air gap that is between the bottom plate and the top,mabe provide a diagram with your measurements of the 900mhz antenna.
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Old Mar 29, 2010, 05:10 PM
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To answer ess's question,the antenna in the above example is for 1.2ghz and the specs say it covers 1080-1200mhz.The specs for L-com's 900mhz antenna are from 902-928mhz,so I don't know how effective they would be at receiving 1040mhz or 1010mhz.Sorry mongrel,I am only interested in the demensions of a regular 900mhz patch,not rc-cam's gp patch.
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Old Mar 29, 2010, 06:29 PM
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Navarre, FL
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Quote:
Originally Posted by up2late View Post
Thank you,Rusty that is what I am looking for.If you have time could you find the measurement for the air gap that is between the bottom plate and the top,mabe provide a diagram with your measurements of the 900mhz antenna.
The plastic housing, and ground plane are exactly the same between the two units, so the air gap is the same as well. I think I called it 14mm, but there's nothing to hold the plates perfectly flat, so it kinda depends on where you measure it.

BTW, Mike (OMM) recently found this link for calculating patch antenna dimensions. Dielectric constant for air is 1. It's VERY impressive,and spot on

http://snipurl.com/v5g7h

Cheers,
Rusty
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Old Mar 30, 2010, 12:15 AM
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Thank's rusty,you have been incredibly helpfull.If you have time maybe you could post some pictures with measurement's of the 900mhz patch.
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