Advice Needed Gregorian dishes

[Captain Jack]

So, almost 1 dB more gain...

 

[RimaNTSS]

How do you folks compare performance of your dishes to make such a conclusions? I mean, can somebody describe the process of comparison.

 

[Captain Jack]

Oh, no. Rimant is here...

 

[Archived-1]

This is interesting.
http://xxx.satellite-calculations.com/Fibo/fibo.htm

Interesting to see the difference in the offset angles for the range.

 

[Archived-1]

How do you folks compare performance of your dishes to make such a conclusions? I mean, can somebody describe the process of comparison.

Well I find the best way is to make new arms for the dish then move the lnb to a new position to locate the Gspot, more Inox later I will make 10 different lnb holders then fine tune the dish in, how about you Rimants















Only a bit of fun Rimants keep up the good work

 

[RimaNTSS]

I like fun and like jokes I also understand that each joke usually contains some joke in
But, seriously, I do not know proper way how to compare performances of SAT-systems (antenna, feedhorn, LNB . And statement like: antenna A is better than antenna B tells me nothing, unless we speak about materiel antennas made of, color they are painted or size of the reflector. Then, yes, we can say that plastic dish is better than metal one, aluminum sometimes is better than steel, gray is nicer than white and bigger is always better.
But, SAT-system A is performing identically to the system B, than so many questions can arise, like: on which satellite, which transponder, at what time of the day, what are the weather conditions measurements taken and so on.
I do not know common procedure for comparison. Who knows?

 

[Captain Jack]

I think for the "common" people, if they see better performance (i.e. higher SNR dB levels) better on dish A than on dish B in the same location with same LNB, cable and receiver, then they'll conclude that dish A is better.

That's ignoring Le G spot, as all dishes are assumed to have the correct positioning of the LNB worked out by the manufacturer...

 

[RimaNTSS]

I think for the "common" people, if they see better performance (i.e. higher SNR dB levels) better on dish A than on dish B in the same location with same LNB, cable and receiver, then they'll conclude that dish A is better.

Yes, they do not take in account that SNR dB can change in couple of minutes +/- 3%, do not take in account that there are variations of SNR dB during day +/- 10%. Usually there is not same LNB for offset and Gregory dishes. And when they say better..... how much better is that? We have no idea, OK, I have no idea.

 

[Captain Jack]

This is already taking it beyond what a normal person would look for. If dish A gave no pixelations where dish B does (let's assume same LNB here) then dish A is "better".

 

[RimaNTSS]

At what time of the day?
This screenshot is representing variations of signal during 24 hours. Than 7 AM looks better than 2 PM, and dish used in the morning time will be better than the afternoon dish.
And I will keep quiet that not all normal persons adjust skew of LNB perfectly, but this makes big difference.

 

[Archived-1]

Ive been testing a few lnbs on weak signals and I don't know what all the hype is all about with the black ultra, I certainly wont be using one again,

Ive got to agree with you Rimants certain times of day conditions can make all the difference from lock/no lock.

 

[samoloko]

well
I can say from experience that CJ Is right
It Is up to Installer to rate quality of a given dish - when you have a dish some time you know how It perform 24/7 - then you can compare to other dish
BTW How do you fine adjust skew using your fibo dishes - Is that possible at all

 

[Captain Jack]

Skew adjustment is possible on the Fibo. You need to undo the little screw in the feedhorn and rotate the LNB and the C120 adapter it's attached to.

 

[TJExcalibur]

Ive been testing a few lnbs on weak signals and I don't know what all the hype is all about with the black ultra, I certainly wont be using one again,

Ive got to agree with you Rimants certain times of day conditions can make all the difference from lock/no lock.

I have to agree. Got a new Black Ultra for my setup and as I was given a Invacom TWH -031 0.3dB I thought I would give it a try. In both cases I laid flat on the roof whilst a friend read the dB readings over the phone intercom as I adjusted the skew and depth from the dish. The Invacom TWH -031 0.3dB gave me 2% more on BBC World News Thor 10778 H 24500.
Maybe it would be different on other sats.

 

[Archived-1]

Ive been testing an o.2 db technomate lnb against the BU, the tm is far better for weak signals, I am going to order a 0.1 db and do further tests.

 

[nelson_b]

well - when you have a dish some time you know how It perform 24/7 - then you can compare to other dish

yes - i think that in general this is a good way to compare/judge a dish - and all that would be required for most users.

However ... once you move into the area of fringe reception, general rules no longer really seem to apply - and there are just too many variables to make direct comparisons !

 

[skomedal]

However ... once you move into the area of fringe reception, general rules no longer really seem to apply - and there are just too many variables to make direct comparisons !

Yep you hit the nail on the head with that statement

Too many variables

Regards

 

[RimaNTSS]

However ... once you move into the area of fringe reception, general rules no longer really seem to apply - and there are just too many variables to make direct comparisons !

Totally agree with you, but, nevertheless if System A performs better than System B, than it will be performing better all the times, does not matter it is fringe or not fringe reception. Saying that, it is still possible to make comparison of performance of systems, and, at the end of the day say how better system A performs than system B, we just do not know how to do that. We do not know step-by-step process, but there should be one, that is for sure.

 

[archive10]

Speaking of Fibo's, there's a guy trying to sell what looks like a non-gregorian Philips-branded Fibo on the local ebay-equivalent.
Never seen this before - was this a common option for Fibos?

 

[RimaNTSS]

This is genuine version of Fibo, made for multifeed. I, personally, do not see any value to go for this antenna, as it is simple offset dish. It misses main part to be Gregorian- the subreflector.