Dish size - was RE: [MLB-WIRELESS] linux expert help needed

[Hamish Moffatt]

On Mon, Dec 10, 2001 at 11:38:53AM +1100, Adrian Close wrote:
> On Mon, 10 Dec 2001, Tony Langdon wrote:
> 
> > Depends on the size of the dish.  Basically, size is (ahem) everything. ;-)
> > The bigger the dish, the more gain - that goes for the grid packs as well.
> 
> I was given to understand that dish size had an effect on beam width as
> well - the upshot being that larger dishes are harder to aim...

That's quite right. You have attenuated signals in some directions
to increase the signal in another.

If you sum the gain of the antenna in all directions (azimuth
and elevation) the sum must be 0. If you have 8 dBi in some
direction, you must have -8 dBi in some other direction
to compensate. 

The hypothetical isotropic radiator is the reference; it has equal 
gain in every direction, 0 dBi.


regards,
Hamish
-- 
Hamish Moffatt VK3SB <hamish at debian.org> <hamish at cloud.net.au>

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