On 01/23/2013 07:08 AM, Jim Lux wrote:
On 1/22/13 9:08 AM, Joe Leikhim wrote:
John;
You might look into building your own, _scaling up_ from a G3RUH design
(2.4 GHz)
note that they were illuminating a 60 cm dish in those experiments,
that's not a very big reflector for 12.5 cm wavelength at 2.4 GHz. not
even 5 lambda. I'm not sure you can really model that system by physical
optics.
the OP wants to illuminate 120 cm for 1.5GHz, 20 cm lambda.. that's 6
lambda. Still a pretty small dish, wavelength wise.
Both will have issues with diffraction around the edges, so if you're
worried about noise temperature, you'd want to seriously under illuminate.
First degree surpression of reflexes will also be lost, it will be the
antenna gain that get some additional benefit, but the offset would have
been better for a larger dish.
Cheers,
Magnus
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