[Space] Debriefing Notes

grog at piratelabs.com grog at piratelabs.com
Thu Feb 11 04:42:52 PST 2010


Ed's right... but even in this previous situation, a dipole would probably have been a major improvement over the configuration that was used.  

On the other hand, a vertical dipole made out of coax would be cheap and less prone to damage from a landing.  it could hang from the payload section and stay (mostly - wind dependent) vertical with a fishing-line weight attached to it.  

Gregory Stramback
grog at pirate.org




On Feb 11, 2010, at 1:10 AM, Ed Moore wrote:

> 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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