[Space] Debriefing Notes

Ed Moore eam52 at cam.ac.uk
Thu Feb 11 01:10:43 PST 2010


Radiation pattern - with a vertical dipole, half of the energy gets radiated up into space. with a ground plane and downward facing quarter-wave, the energy gets radiated from the horizon down (apart from a null along the axis of the antenna in both cases).

	- Ed


On 11 Feb 2010, at 09:05, Christie Dudley wrote:

> I was talking to a friend tonight about this problem.  He suggested instead of depending on a ground plane, that we should instead use a dipole.  What are your thoughts on that?
> 
> Christie
> _______
> "The road of excess leads to the palace of wisdom." -- W. Blake.
> 
> The outer bounds is only the beginning. http://www.flickr.com/photos/genriel/sets/72157623376093724/
> 
> 
> On Wed, Feb 10, 2010 at 11:35 PM, <nils at shkoo.com> wrote:
> Cool. Googling "ground plane antenna" shows some promising hits; they mostly look like they put 4 horizontal wires in a plus-shaped configuration.  (Greg, I think this is what you suggested a couple weeks ago).
> 
> I found an antenna simulation program here that one can use to simulate the radiation pattern of a given antenna:
> 
> http://home.ict.nl/~arivoors/
> 
> It's not working very reliably under my wine installation; perhaps someone else can have better luck.
> 
> -nils
> 
> 
> On Wed, 10 Feb 2010, Greg Stramback wrote:
> 
> Well, you're using VHF on the 2m ham band. The groundplane should be a
> minimum of 19" radius from the center feed point / radial.
> 
> On Wednesday, February 10, 2010, Jonathan Moore <moore at eds.org> wrote:
> On Wed, Feb 10, 2010 at 8:30 PM, Christie Dudley <longobord at gmail.com> wrote:
> How big of a ground plane do you need?  We had a bit of a metal plate, but
> it was pretty small, relatively speaking.
> 
> It depends on how the antaina was designed.um
> 
> -Jonathan
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