[Moon-net] metallic pool or glass fiber pool ; that te question

[Edward Cole]

At 01:37 AM 7/1/2008, SM5LE wrote:
>Hello
>
>
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>Just finished measurements for metallic pool versa isolated, glass 
>fiber pool , to see if  I could fine any influence.
>
>The results you find here:
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>  http://web.telia.com/~u14901544/
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>Results: the sun noise was 0.2 dB worse (less) with metallic pool 
>and echo's was 0.8 dB worse (less) metallic pool.
>
>Those results go for my 2.2 m dish.
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>73 Sven SM5LE
>
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Very interesting study.  You ask why the WSJT echo peak is in a 
different focal point from the peak sun noise.

Here's a guess:  I note that the echo has several periodic peaks as 
focal distance changes.  Could that be because of a standing wave 
formed by reflected power from the dish?  Since WSJT is single-tone 
SSB (essentially a changing freq carrier - FSK) the WSJT signal is 
coherent while sun noise is incoherent or random noise.  The SWR 
effect is not seen on sun noise perhaps because of the nearly 
infinite range of frequencies in the complex wide-band noise?

What do you think?

73 Ed - KL7UW
I would like to see a comparison of tripod feed support legs vs. non-mettalic.