 |
 |
 |
|
Dec 23, 2010, 09:58 AM
|
|
|
Germany
Joined Dec 2010
37 Posts
|
Circular-polarized Patch Antenna for 5,8 GHz
I found this 13dbi patch for 5,8GHZ
http://www.wirelessnetworkproducts.com/hd27073.aspx What does the experts here think? Any good for our application? Best regards Christian |
|
|
|
|
|
Dec 23, 2010, 11:53 AM
|
|
|
Netherlands, NH, Edam
Joined Jul 2004
5,535 Posts
|
Overpriced ...
Cheers, Sander. |
|
|
|
|
Dec 23, 2010, 12:26 PM
|
|
|
Germany
Joined Dec 2010
37 Posts
|
Jupp, besides that.... half the price would be better.
From my understanding i will lose about 3db gain due to the circular polarization. As a benefit i can fly more acrobatics, right? Do you have any experiences with circular polarized 5,8 ghz patches? Not that easy to find. Maybe you have other recommendations? Thanks Christian |
|
|
|
|
Dec 23, 2010, 02:37 PM
|
|
|
SW England
Joined Aug 2009
789 Posts
|
|
|
|
|
|
Dec 23, 2010, 05:08 PM
|
|
Amherst, VA
Joined Jun 2006
9,174 Posts
|
RIPOFF!!! For two peices of metal less than 3" square $120!!!
And I can assure you that it's not even really circularly polarized but elliptical. Coyote64 was kind enough to open up one of his and shoew it to me. I'll post a how-to on it soon enough. It would be really easy to build  -Alex |
 |
Latest blog entry: Project Covert Ops: Long range ground...
|
|
Dec 23, 2010, 05:31 PM
|
||
Gilbert AZ
Joined Jun 2010
216 Posts
|
Quote:
|
|
|
|
|
|
|
Dec 24, 2010, 01:21 AM
|
|
|
Germany
Joined Dec 2010
37 Posts
|
Hi Alex,
i am definitly looking forward to your howto. Allready enjoyed all your other DIYs. Best regards Christian |
|
|
|
|
Dec 24, 2010, 02:35 AM
|
|
Qld, AU
Joined Sep 2007
445 Posts
|
Subscribed !
|
|
|
|
|
Dec 24, 2010, 05:33 AM
|
|
|
Joined Mar 2009
514 Posts
|
Notice the important remark from lonestar : if your tranmitter antenna is linearly polarized and your receiver antenna is circularly polarized, which is the case discussed here, then you always loose 3dB.
The best case would be to have a circular polarized antenna at the transmitter and at the receiver (it is the case for GPS for example). more details here : http://www.antenna-theory.com/basics/antennapol.php "Suppose now that a linearly polarized antenna is trying to receive a circularly polarized wave. Equivalently, suppose a circularly polarized antenna is trying to receive a linearly polarized wave. What is the resulting Polarization Loss Factor? Recall that circular polarization is really two orthongal linear polarized waves 90 degrees out of phase. Hence, a linearly polarized (LP) antenna will simply pick up the in-phase component of the circularly polarized (CP) wave. As a result, the LP antenna will have a polarization mismatch loss of 0.5 (-3dB), no matter what the angle the LP antenna is rotated to." |
|
|
|
|
Dec 24, 2010, 10:56 AM
|
|
|
Amherst, VA
Joined Jun 2006
9,174 Posts
|
Yes, CP is best when both TX and RX have circular polarization in the same rotation (RHCP or LHCP). I am working on new CP systems. Right now I only have the skew planar wheel antenna tested. I have a helical being tested by dalbert in Florida. I'll make the how-to's as I have time
-Alex |
|
|
Latest blog entry: Project Covert Ops: Long range ground...
|
|
Dec 24, 2010, 01:25 PM
|
|
United States, IL, Champaign
Joined Apr 2002
985 Posts
|
my friend here has been very happy with this iftron 5.8 circular patch on a hobbywireless 200 mw system. http://www.iftrontech.com/Antennas-&...duct_info.html
|
|
|
|
|
Dec 24, 2010, 02:07 PM
|
||
Canada,Quebec
Joined Jan 2005
1,863 Posts
|
Quote:
|
|
|
|
|
|
|
Dec 24, 2010, 03:40 PM
|
|
|
Amherst, VA
Joined Jun 2006
9,174 Posts
|
These antennas attampt to skew the polarization using edge trimming methods. The problem is that the antenna still retains most of it's linear capabilities and only skews the pattern slightly. What results is an elipse for a polarization pattern. This is very good for when you have a linear TX antenna as you will have about 1-2db loss (instead of 3db) when up right and about 5-6db loss in a 90 degree bank. However with a circular TX antenna, there will be some loss and might not reject multipath interference as well.
-Alex |
|
|
Latest blog entry: Project Covert Ops: Long range ground...
|
|
Dec 24, 2010, 03:58 PM
|
||
United States, FL
Joined Nov 2006
846 Posts
|
Quote:
|
|
|
|
|
|
|
Dec 25, 2010, 03:35 AM
|
|
|
Germany
Joined Dec 2010
37 Posts
|
Merry Christmas to all of you....:-)
This link gives design guidelines for a circular polarized patch antenna: http://icom.hsr.ch/uploads/media/MegnetMathisRom.pdf Published on a Conference in 2009. D. Megnet, H. Mathis, Circular Polarized Patch Antenna for 5.8 GHz Dedicated Short-Range Communication, 39. European Microwave Conference (EuMC) 2009, Rome, Italy, September 28 - October 2, pp. 638-641. Its so nice to read scientific papers also for hobby purposes and not only at work ;-)) |
|
|
|
|
|
|
«
Previous Thread
|
Next Thread
»
| Thread Tools | |
Similar Threads
|
||||
| Thread | Thread Starter | Forum | Replies | Last Post |
| Mini-HowTo The Skew-Planar Wheel circular polarized omni antenna | IBCrazy | Video Piloting (FPV/RPV) | 828 | Today 09:28 AM |
| Discussion Left/Right circular polarized antenna ? | SpookiePower | Video Piloting (FPV/RPV) | 44 | Jun 04, 2011 06:41 PM |
| Discussion Best solution for antenna tracker and 5.8 GHz diversity | Lomcevac | Video Piloting (FPV/RPV) | 0 | Nov 28, 2010 07:33 AM |
| Discussion 18dbi Circular Polarized Patch ? | Coyote64 | Video Piloting (FPV/RPV) | 3 | Nov 10, 2010 04:59 PM |
| Discussion Advantage of a Circular Polarized Patch Ant? | Mach61 | Video Piloting (FPV/RPV) | 2 | May 01, 2009 10:53 PM |
|
|