CaptKiwi 0 Posted June 2, 2009 Report Share Posted June 2, 2009 (edited) Hello, just wanted to share this with you guys. I came across a nice simple patch antenna which is easy to make and has a wide beam angle of 70° 11 dbi Circulary Polarized Antenna Some Specs: Frequency : 2.400 - 2.500 GHz Gain : 11 dBiVSWR : < 1.22 POLARIZATION : Circular BEAM WIDTH • Horizontal: 70° • Vertical: 70° IMPEDANCE • 50 Ohms DIMENSIONS • 25 x 102 x 102 mm To get a wider beam width just set them in a array configuration. Array antenna Will let you now when I tested this patch antenna ! ** Attached is the circle in fullsize. Edited June 2, 2009 by CaptKiwi Quote Link to post Share on other sites
Terry 5 Posted June 2, 2009 Report Share Posted June 2, 2009 I made one like that a while back but I could not get it to work well. Terry Quote Link to post Share on other sites
W3FJW-Ron 0 Posted June 2, 2009 Report Share Posted June 2, 2009 If indeed it is circular polarization, there will be a lot of db loss with a horizontal or vertical polarized antenna on the aircraft. Quote Link to post Share on other sites
Kilrah 2 Posted June 3, 2009 Report Share Posted June 3, 2009 If indeed it is circular polarization, there will be a lot of db loss with a horizontal or vertical polarized antenna on the aircraft. Not much, 3dB if I remember well. And in return, you avoid the -25dB or so you would get with a linearly polarised antanna when it's cross-polarised (oriented perpendicularly to the TX antenna). In theory, it's more down to a (simplified) choice of "good all the time" vs "excellent in some conditions but awful in others". But the most important is practice, and when testing linear 8dB vs circular 8dB I was having better quality with the linear one throughout an standard flight. So I stayed with linear ones. Might me more tricky if you don't know how to arrange your antennas though, the circular could be giving better results in that case. Quote Link to post Share on other sites
W3FJW-Ron 0 Posted June 3, 2009 Report Share Posted June 3, 2009 Personally, I wouldn't trust it. Haven't looked at db tables for a long time but IIRC a 3db loss equates to a 50% loss in signal strength which would affect the range. Probably immaterial at the distances we fly at though. Quote Link to post Share on other sites
Kilrah 2 Posted June 3, 2009 Report Share Posted June 3, 2009 3dB indeed equates to 50% less signal power, which in turns means a 0.7x factor in range. It'snot a big price to pay to avoid signal losses due to bad orientations, but as said (at least for me) it didn't cut it in practice. Quote Link to post Share on other sites
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