Re: [IRCA] Wellbrook versus Beverage comparisons

[Nick Hall-Patch <nhp@xxxxxxxx>]

At 13:12 11/9/2009, you wrote:
>Nick Hall-Patch wrote:
>
>>I don't really know the technical reasons
>>for this, but it makes sense that a big antenna will deliver a more
>>robust signal than a smaller one will.
>
>It's all about the aperture of the antenna.
>
>Even though the larger antenna has a less-tight F/B or forward lobe, the fact that it is physically larger means that it is coupled into a greater area of space. So it has a larger aperture.
>
>Because of this, i.e. it's coupling into a larger physical area, it can average out the effects of ionospheric refraction of the signal, fading, etc. over a larger area. This often is perceived as a better signal, or a steadier signal.
>
>Hope that made sense.

Thanks for replying on this Rick.   The explanation does ring a few bells (my antenna theory is pretty rusty, and I never considered it to be great). 

I guess I'm not surprised that a 450m Beverage antenna does a better job of sampling a wavefront than a phased small antenna system of 40m spacing, as one is a wavelength or more at MW frequencies, while the other is a smallish fraction a of a wavelength.

But I'm a tad surprised that a 7m x 15m corner fed loop gives noticeably better reception than a 5m x10m Flag even if it's also a "splashier" signal, as both are a very small fraction of a wavelength.   Perhaps your explanation gives way to mine (that when there is so little signal available for demodulation, that a small increase makes a significant improvement in the output signal's readability) with these small antennas, and that my comparison of the Grayland antennas and mine was not apt?

Thanks again for getting the brain cells working a bit.

best wishes,

Nick



*****************************
Nick Hall-Patch
Victoria, BC
Canada 

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