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AirNav RadarBox and RadarBox24.com => AirNav RadarBox and RadarBox24.com Discussion => Topic started by: G7PHN on February 11, 2009, 09:44:16 AM

Title: Homebrew Antenna.?
Post by: G7PHN on February 11, 2009, 09:44:16 AM

Just wondering if anyone has a design for a multiple 12x  1/2wave over 1/2wave antenna.?

The standard i imagine is 1/2 wave over 1/2 wave.?

Title: Re: Homebrew Antenna.?
Post by: juangelb on February 14, 2009, 08:47:03 PM

Hi G7PHN

I did several Coax Colinear antenas based on the following project link,
fot 2.4 Ghzs and I did redo the the calc to 190 Mhz  :

http://www.nodomainname.co.uk/Omnicolinear/2-4collinear.htm

Even the 8 dipoles model worked better than Wimo.
I constructed with 8, 18 and 21 dipoles all working fine.
I think that 8 dipoles is enough.


Cheers

Title: Re: Homebrew Antenna.?
Post by: Allocator on February 14, 2009, 09:02:48 PM

That will be 1090MHz rather than 190MHz

Title: Re: Homebrew Antenna.?
Post by: G7PHN on February 14, 2009, 09:04:37 PM

Yes I had already seen that one and a few simillar designs but am now a little worried about the angle of radiation being bought too low down. Not a problem for those high up, but with me living in an area full of obstructions I thought it may do more harm than good.?

Title: Re: Homebrew Antenna.?
Post by: Fenris on February 14, 2009, 11:07:55 PM

Quote from: G7PHN on February 14, 2009, 09:04:37 PM

Yes I had already seen that one and a few simillar designs but am now a little worried about the angle of radiation being bought too low down. Not a problem for those high up, but with me living in an area full of obstructions I thought it may do more harm than good.?

Well not really, the worst problem is always going to be at low angles, anything above that is LOS, so putting the peak gain in the worst direction makes sense.