[MLB-WIRELESS] Dish Focal Length?

[Ratbaggy]

Mark,

You can calculate the focal length of the dish using this formula:-

f = Diameter squared / (16 * depth)

The phase centre of your feed then needs to go in the focus.  The phase
centre of a simple dipole and reflector type feed will be roughly half way
between the driven element and the reflector.

This should give you a good enough starting point and then you can make some
small adjustments for maximum gain.

David.



----- Original Message -----
From: <vk3jma at net2000.com.au>
To: <melbwireless at wireless.org.au>
Sent: Tuesday, May 18, 2004 7:51 AM
Subject: [MLB-WIRELESS] Dish Focal Length?


> Hello,
>
> A friend of mine has obtained a "Pacific" dish. One of the white
painted/coated
> MDS ones.  But only the reflector.
>
> Does any one have the measurement of the focal lenght, ie, reflector grid
to
> driven element would be best as I have no idea what feed type he wants to
use.
>
> Many thanks.
>
> Mark
>
>
>
>
>
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