>From the following references:
http://en.wikipedia.org/wiki/Parabolic_antenna
http://www.analyzemath.com/parabola/parabola_focus.html
It would appear that the focus is calculated as follows:
(dia Squared)/(16 x Depth)
The general equation of a parabola is y =3D x2 / 4f where f=3Dfocus
Chris
-----Original Message-----
From:
On Behalf Of John Tudor
Sent: 02 April 2008 10:51
To:
Subject: Re: [Nature Recordists] AT3032 matching & Telinga questions
Measure the diametre of the dish.
Lay a ruler across the dish and measure the depth in the centre
The formula for finding the focus of a Parabloa is as follows
(Dia Squared)/(4 x Depth)
Example. Dish is 1200mm in dia (1200 Squared is 1,440,000)
Depth is 600 mm deep at the centre (4 X 600 =3D 2,400)
1,440,000 / 2400 =3D 600
So the focus is 600 mm out from the centre
Fine tune it from there
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