Mesh Holes

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Pittsville

SatelliteGuys Pro
Original poster
Jul 4, 2006
164
3
38N 75W
I just got a 10' Channel Master dish and one of the panels has a few holes in the mesh. They look like they might be bullet holes. They're not very big.

How critical is the integrity of the mesh on the C band dishs? Do the signals seek out holes in the mesh and try to escape through them to avoid being watched? I know the parabolic formation of the dish is important but will a few mesh holes here and there make much difference?

Overall the dish is in very good condition I would say. It came with a Gardiner model C95-45 LNB with 45 degree noise figure. What kind of performance might I expect out of that, assuming it is in working order? I hope to be able to get the Ku/C LNB from Sadoun some day but in the meantime I am going to see what I can do with the stuff I have for C band. I also have some kind of Chapparal LNB that came with another dish (Unimesh 7.5'). and it's noise temperature is 35. Any opinions on which one would be better to use?
 
You should be fine... the 45k Lnb is old school by todays standards but should pick up fine (with sparklys) the 35 is better, (the lower the noise temp the better) I started out with a 120k LNA and a 10'... I have a 25 k on my 10' and a 17k on my 8' mesh now...
 
There is someone around that posted a few months ago who is missing an entire panel (dish looks like pacman) and he commented that the picture was great.
 
I just got a 10' Channel Master dish and one of the panels has a few holes in the mesh. They look like they might be bullet holes. They're not very big.

How critical is the integrity of the mesh on the C band dishs? Do the signals seek out holes in the mesh and try to escape through them to avoid being watched? I know the parabolic formation of the dish is important but will a few mesh holes here and there make much difference?

Overall the dish is in very good condition I would say. It came with a Gardiner model C95-45 LNB with 45 degree noise figure. What kind of performance might I expect out of that, assuming it is in working order? I hope to be able to get the Ku/C LNB from Sadoun some day but in the meantime I am going to see what I can do with the stuff I have for C band. I also have some kind of Chapparal LNB that came with another dish (Unimesh 7.5'). and it's noise temperature is 35. Any opinions on which one would be better to use?


While any imperfections in the reflector will degrade performance, with the satellites being so much stronger than back in the day you should be okay.

Concerning the LNB's Gardner was a very fine product, while the Chaparral 35 you have may say it has a lower noise figure the Gardner could out perform it. The only way to know for sure is to try both and see what works better. There easy to swap out so once the dish is up and running and aligned play swap around and see what works best. LNB numbers sometimes don't tell the whole story.
 
Pittsville:

If the dish is to be used for C Band reception openings larger than 5/8" could theoretically be a problem. If all openings were that large, efficiency would suffer, however only a few openings wouldn't be noticed. For Ku Band reception, that opening dimension is less than 1/4". A No.2 pencil is a good go-no go guage. If the pencil will pass thru the openings, efficiency will suffer greatly and the dish is not adequate for Ku reception.

Surface accuracy of the parabolic reflector is much more critical than the size of the openings. Deviations as little as 1/16" of an inch start to reduce efficiency. Signals arriving at the focal point are an average of the surface accuracy. Deviations from a perfect parabolic surface subtract from the focused signals because they arrive there out of phase with "good" signals. For each out of phase signal a "good" signal is cancelled out.

Analog signals are also a factor. As signal strength surpasses the threshold detection level of the receiver, sparklies begin to go away and at some point, more gain makes little or no difference. That's what happened with the system with a missing dish petal. Digital signals work a little differently with a much lower detection level and sparklies are replaced by dropped pixials or a frozen picture.

Hope I didn't bore you with this,
Harold
 
a couple little holes will not be a problem. Of course many of us strive for perfection with our setups and a lot of us would change the mesh but a couple of "bullet hole" sized perforations will not noticeably affect reception.

Like the previous post states, One member had a whole panel missing and still had good reception.

The biggest thing is to be sure the dish is not warped.
 
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