Gain figures?

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AceB

SatelliteGuys Family
Original poster
Aug 1, 2011
48
48
Sussex, UK
I've got the chance to relocate my dish from it's current location to another spot in the garden that will give me much better coverage of the easterly horizon. I already have a 1.2m that gets me close to 70°E of south (I'm at 0.003°E) but the new spot means the 1.8m should be able to reach 64°E, currently it stops around 40°E.

My main reason for moving it is C Band and to that end I've toyed with the idea of puting in a bigger dish but here's the snag. One thing I can't afford to do is install a 2.4 or 3M quality solid aluminium dish like my current 1.8M Precision Antennas spun reflector so the option would be to install a mesh dish if I can source one. I have the gain figures for this but what I'm after are reliable figures for 8 and 10ft mesh dishes, it's really quite difficult finding them other than those listed on Alibaba as I don't know of anyone in the US still selling them. Any large dish is a rare find this side of the pond, the 10ft'er you might be able to pick up free if you dismantle it I'd be happy paying $400 for it.

I know the Ku performance of a mesh can be quite poor but I'd appreciate any comments on mesh performance at Ku. There are times when I need to put Ku on the bigger dish so I'm still undecided whether a larger mesh dish is the way to go or not.

These are the quoted figures for my 1.8M solid reflector.

C-Band low mid high
Prec1.8m 34.9 35.5 36.0

Ku Band low mid high
Prec1.8m 44.1 44.7 45.3
 
The mesh dishes sourced from the average China supplier are not provided with specs let alone compliance verification. Only the best manufacturers provide this on their top of the line builds. Usually the spec sheets are copies of another site. The only specs and compliance that I would tend to trust would be the TX/RX with compliance certification.

The performance on these generic RX dishes will even vary within the lot. Some dishes have formed mesh others have flat, some have 6 panels others have 8, 10 or 12. Too many factors here to even suggest what a generic mesh performance would be on KU.

Gain figures are less important than the beam width and surface efficiency. Yes, bigger could be better, but the additional gain won't matter if the main lobe is wide with significant side lobes and other noise induced by surface inaccuracies.

With experience and certainty I will assure you that your 1.8 Precision spun reflector will significantly outperform on KU-band any 2.4m generic Chinese mesh panel.
 
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Thanks Brian for a really useful and informative reply. There is so little information about performance I started working on what I could find which are simple gain figures but some of the claims made me question them. Still not really sure what route to take on this, it is primarily for C Band so I can forgo the extra Ku gain I achieve with the 1.8 over the 1.2 if I can improve C Band by installing a larger mesh dish. I may make a few enquiries about these Chinese things but only if I can get one here at the right price as I don't mind throwing money away on worthwhile experiments.
 
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