Re: QO-100

Andy G4JNT

Not sure I do either - in the traditional    2.D²/λ   sense
But when the transmitter is not a point source (not diffraction limited, I think, in optical terms)  there must be some name for it.
The sun is 0.6° wide, so any antenna beamwidth narrower than that gets 'interesting'


On Sat, 5 Jun 2021 at 20:17, Dave G8KHU <david@...> wrote:
<< the sun's near field. >>

Not sure I completely agree with that Andy.

If the sun is a single source driving a sun diameter antenna, then yes indeed.

If you consider the sun to be an enormous array of coherent radiaters, then again yes.

However if the sun is considered as an enourmous array of non-coherent, independant small radiators then wouldn't the effective near/Fresnel/far field boundaries would be determined by the geometery of the individual radiator rather than the array geometry?

Dasve G8KHU

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