Satellite meter, Constellation Screen ?

[Magic Static]

What information does this give you? And how do you use it?

 

[Scott Greczkowski]

Good question I have wondered that myself. I have a Superbuddy and notice that as one of the options and have never used it before.

 

[WhyMe1]

Constellation diagram - Wikipedia, the free encyclopedia

[url]http://www.authorstream.com/Presentation/Seeker84-313696-intro-qam-measurements-understanding-rev1-science-technology-ppt-powerpoint/
[/URL]

 

[Magic Static]

OK then. And I thought deciphering ignition waveform patterns was tough. Well once you get used to looking at different modulations on the constellation screen, it will be a nice diagnostic tool for those weird reception problems. Thanks WhyMe1

 

[WhyMe1]

OK then. And I thought deciphering ignition waveform patterns was tough. Well once you get used to looking at different modulations on the constellation screen, it will be a nice diagnostic tool for those weird reception problems. Thanks WhyMe1

You're welcome. This hobby just keeps getting better and better if you're a tinkerer So much to learn and play with!

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[Magic Static]

This screen can tell you if you have a tuning problem or a cheap LNB from China problem or if buying some expensive Norsat PLLs will help at all.

 

[Franky_D]

This screen can tell you if you have a tuning problem or a cheap LNB from China problem or if buying some expensive Norsat PLLs will help at all.

Hi,

I would appreciate if you explain in simple language (I find wiki-link a bit too tech) what exactly to look for in each of the following cases to conclude if:
1) you have a tuning problem or
2) a cheap LNB from China problem or
3) buying some expensive Norsat PLLs will help at all

I am attaching generic pictures of constellation screen for my meter, both SD and HD transponders.



Thanks a million for advice!

 

[updatelee]

It not only tells you the order of modulation but gives you and idea of the quality of the phase relationships

UDL

 

[Franky_D]

It not only tells you the order of modulation but gives you and idea of the quality of the phase relationships

UDL

WOuld it be possible to link observations to what I see on the constellation screen? Like, if the dots are wide spread, it means, the LNB is cheap n useless... Or if dots are .... one will benefit in changing to Norsat...
Would it be too simplistic?

 

[updatelee]

not really, how far the dots are out is based on the amplitude of the phase but the tuner uses its agc to normalize the values so that it can decide the signal best, so if the lnb has low gain the tuner just compensates. Now the tightness of the dots does give an indication of the signal quality coming down the coax, if the signal should be good all things considering yet the dots are not right compared to another lb it could indicate very poor phase noise in the lnbs LO

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