LNB mounting position..........The 129 Project

[Greg Mueller]

I built a bracket to hold the DP LNB where the Primestar LNB was. But there's a lot of physical difference in the "length" of the two.

So is it the "mouth" of the LNB that wants to be in the same position or the "body"?

In other words is it the front opening of the LNB that wants to be at the focal point of the dish?

 

[Miner]

Greg,

I'd make the bracket so the front opening of the LNB is the same distance (and angle) as the primestar LNB. If you could build some adjustability into the bracket to move it closer or farther away from the dish, it may prove extra useful for fine tuning.

Mark

 

[Greg Mueller]

I was hoping that was the case.....
I took the white plastic cover of a Dish legacy LNB so I could measure how far the plastic sticks out in front of the edge of the "feed horn". It turns out the white plastic is about 10mm (.393") further out. The old Primestar LNB measured about 1.4" from the plastic mount of the 1.2 meter dish, toward the dish. When I mounted up the Dish LNB I could get the feed horn about 1.4" from the plastic mount too, with about 1/2" adjusting distance on the dish side and the non dish side, so I'm right in the middle of my adjustment travel.