Dish Focal distance

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Eastcoast

SatelliteGuys Pro
Original poster
Mar 18, 2006
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Newfoundland,Canada
Hi Guys

I am using a Starchoice STAR100 1 M dish and the instructions that were in the box are exacty the same as the Winegard 1M. The Winegard speccs say the focal distance is 59 cm, my question is that 59 cm measured from the center of the dish to face of the lnbf? I ask this because the starchoice dish was supposed to have that stacked lnb and I'm not familiar with it and if it is longer making the face closer to the dish.I measured my lnbf to the dish and it is 64 cm.

Dave
 

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Perhaps somebody out there that has a Winegard 1 M dish and doesn't have to climb up on the roof could measure from the center of those for bolts on the front of the dish to the face of the LNBF and let me know what they see.

Dave
 
The focal point of the reflector is slightly inside the scalar cover of the LNBF. Measuring from the top of the dish to the focal point 40.17in, from the bottom of the dish to the focal point 23.07in and from the centre of the dish to the focal point 26.22in. The centre of the dish is at the centre of the mounting bracket at the back of the dish. If you make an X out of the four bolts attaching the pan of the dish to the bracket, that is the center of the dish and the point to measure from. I did at one time have a scan of the document from Winegard showing this, but my scanner is no longer connected.

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Thanks Larry1

That is a great help as I think the lnbf holder is not right as I read the guys saying when you install a lnbf to move it as far back in the holder as it will go and I tried that but the Sig/Quality is better as far forward as it go.
Thanks again and I will search for that info you referred to.
Also thanks Pete for that link it has some interesting stuff.

Dave
 
No problem, the drawings speak for themselves, I would use the signal quality as your guide THATS what its all about :)
 
I did find that I had to bend my LNBF arm some to match the drawing. Also, tighening the bolts holding the arm makes a drastic difference in where the arm is positioned. The trick I used was to use a piece of string with a mark from an ink marker at the focal point, taped to the top and bottom of the dish as a guide when adjusting the arm, then measuring the center measurement as a double check. Once the arm was positioned properly, then use your QUALITY meter on your satellite box to fine tune to. (unless you have a spectrum analizer)
 
Larry
Thanks very much and I will give that a try this weekend if we don't get freezing rain like last Saturday.That was terrible and I hope we're finished with that kind of weather!

Dave
 
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