LNBF Comparison Test of 8 Available KU Band LNBFs - April 5th, 2012

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I spent a ton of money buying two new "NJR" universal lnb's to set up on this orthomode feed. These are current model PLL , but only performed marginally better than my Invacom SNN-031. Don't know what to say.

Brian, any chance one of your new products could have a C-120 feed mount?


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The results of yesterday's test with the Spitfire performance so much lower than previous tests bugged me all last evening, so I replicated the LNBF test today.

Today, I peaked the dish on Galaxy 19, transponder 12177. The DMSI Spitfire demonstrated a good performance as I had noted in the May, 2011 test. What I can summarize from the testing on a transponder with known adjacent satellite interference (11842) is that some LNBFs reject this off axis "noise" better than others. Overall, the winners are still winners and the losers continue to be losers..... ;)

Enjoy!

LNBF-Comparison_11842_12177.jpg

View attachment LNBF Comparison_11842_12177_Peak.pdf
 
Given the good results of the current Geosat lnbs and similar performance of say sample #5, what would be the advantage of going PLL? Does lack of drift result in any significant advantage?

PLL Sample #5 provides very similar if not improved performance over most existing DRO LNBFs and adds the frequency stability to boot! If stability can be added without decreased performance, why not? :D

We will continue to stock the SL1b (bullet) for the 4 degree spacing applications, but have been looking for a great PLL KU-band LNBF to develop as a Standard LO 10750 unit for the North American market. Two new PLL chipsets were introduced this year that made a tremendous leap forward in performance. Previously, PLL noise levels were typically 1.0dB - 1.8dB NR and there was little advantage to gain stability but get lost in the noise. These new designs have dropped this noise figure into the 0.5 - 0.8dB range which is at or below any other distributor's off the shelf DRO LNBFs with their "imaginary" and BS 0.1db performance claims.
 
At the risk of opening up a technical discussion beyond my comprehension, what would be the real world, ie not theoretical, advantage of zero drift vs. standard lnbs?
 
Pixl said:
I spent a ton of money buying two new "NJR" universal lnb's to set up on this orthomode feed. These are current model PLL , but only performed marginally better than my Invacom SNN-031. Don't know what to say.

Brian, any chance one of your new products could have a C-120 feed mount?


01-08-12_1353.jpg
Take the elbow off the bottom waveguide and you will help your H signals by a few tenths....

I too would like to see a C120 version, but I would need a C120 universal quattro PLL...not asking for much huh...?? :) I'm planning to fabricate my own from one of the good European performers.
 
mr3p said:
At the risk of opening up a technical discussion beyond my comprehension, what would be the real world, ie not theoretical, advantage of zero drift vs. standard lnbs?

For today's standard DVBS / S2 reception a regular user will not find much difference between a DRO and a PLL LNB. You might typically notice a slight reduction in Signal Level and Signal Quality readings, but with the ability to display programming at a lower quality reading.

Off the top of my head two advantages could be:

1. Increased accuracy of frequency logging on blind scans.

2. As more transmissions move into 16, 32 and 64 APSK the frequency stability becomes more important.
 
Take the elbow off the bottom waveguide and you will help your H signals by a few tenths....

Bill,

I've read your recommendation about this in one of your previous posts. I did a before/after test on one of my other dishes and did not see any improvement. I didn't like the lnb sticking out like that so I put the elbow back on.

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Thanks for the useful information, Brian. I hope this post gets moved to the Equipment Review Section when the initial discussions are done, where it will be easy to find for future reference.
 
Pixl, great idea of using red and blue connectors for the horizontal and vertical connections. Did you do the same at the other end to identify the cables?

Yes, separate colors at the other end behind the dish where the Zinwell switch is mounted. Almost looks like I'm organized!

You might like that the lnb cover is the bottom of a white Solo cup. I didn't have a ?RED SOLO CUP?


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