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RE: Primestar 1m dish on 435 mhz



> Subject: [amsat-bb] Primestar 1m dish on 435 mhz
>
>
> I recently acquired a Primestar 1 meter dish and am considering it for a
> helix feed on the 435 uplink. Has anyone tried this or have any comments?
>
> Thanks Alot
> Kent   N8ZRD

Kent -- for a dish to work as a dish, it needs to have a diameter of at
least 5 wavelengths and preferably more. Since 435 MHz = 70 cm, a suitable
dish would be about 4 meters in size.

If you have a dish with a diameter D and the wavelength is lambda, then the
beamwidth will be about D/lambda radians or (57*D)/lambda degrees.

If you tried to put a 435 MHz feed on a dish this size the gain would be in
the 10 dB range, and you can do that well with a small 4 or 5 element yagi.

73 de Tom, W3IWI



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