2 lnb fixed dish - Techwatch Support Forums: Digital & Satellite TV, FTA, Cable, Computers, Mobile Phones, Apple and General Tech Forums

daphney · 13-12-06, 02:39 PM

i am trying to setup a fixed dish with 2 lnbs for a friend they want to recieve both 28e & 19e or 13e i am using a 80cm dish with 2 single lnbs and a sliding mount for 2lnbs there is alot of adjustment so can anyone tell me what is the easiest way?? thanks ( and its nice to see i got redirected to new site keep up the good work..)

dennyjames · 13-05-07, 08:49 AM

I wouldn't say there is an easy way unless you buy a twin monoblock lnb.
With two feeds the line between the feeds is the polarisation angle or slope of the curved line of the orbit. You have the two feeds both set slightly off centre and aim the dish midway between the two satellites. This makes sense if the signals from each satellite are similar level. If one satellite has weak signals it would be better to to use the central feed for that satellite since outer feeds generally give lower performance; this is the case where extra feeds have been added to dishes designed for just one feed.
These figures may help:

Satellites due south of you have polarisations which are about nominal. Satellites to the south east have polarisations which are tilted anticlockwise, facing the satellite. The figure shows the possibilities of 5 feeds or 3 feeds on the dish. The pattern of the feeds is a mirror image of the sky, so in the case of the three feeds, the central feed will be lower down and the two outer ones slightly higher. The polarisation angle is approximately level. For perfection, it is possible to adjust the polarisations of each feed individually and also the spacing to suit the orbit positions. It is a tricky thing to do but is possible with tine setting it up.

lincsat · 13-05-07, 01:45 PM

It's quite easy. Set the prime LNB to the weaker satellite -19e or 13e then adjust the 2nd LNB until you find the 28e satellite.

You can then use 2 downleads or a diseq switch to combine the feeds down 1 cable.

13-12-06, 02:39 PM	#1 (permalink)
daphney Member Join Date: Mar 2006 Posts: 53 Thanks: 0 Thanked 0 Times in 0 Posts	2 lnb fixed dish i am trying to setup a fixed dish with 2 lnbs for a friend they want to recieve both 28e & 19e or 13e i am using a 80cm dish with 2 single lnbs and a sliding mount for 2lnbs there is alot of adjustment so can anyone tell me what is the easiest way?? thanks ( and its nice to see i got redirected to new site keep up the good work..)

13-05-07, 08:49 AM	#2 (permalink)
dennyjames Member Join Date: May 2007 Posts: 78 Thanks: 27 Thanked 6 Times in 6 Posts	Re: 2 lnb fixed dish I wouldn't say there is an easy way unless you buy a twin monoblock lnb. With two feeds the line between the feeds is the polarisation angle or slope of the curved line of the orbit. You have the two feeds both set slightly off centre and aim the dish midway between the two satellites. This makes sense if the signals from each satellite are similar level. If one satellite has weak signals it would be better to to use the central feed for that satellite since outer feeds generally give lower performance; this is the case where extra feeds have been added to dishes designed for just one feed. These figures may help: Satellites due south of you have polarisations which are about nominal. Satellites to the south east have polarisations which are tilted anticlockwise, facing the satellite. The figure shows the possibilities of 5 feeds or 3 feeds on the dish. The pattern of the feeds is a mirror image of the sky, so in the case of the three feeds, the central feed will be lower down and the two outer ones slightly higher. The polarisation angle is approximately level. For perfection, it is possible to adjust the polarisations of each feed individually and also the spacing to suit the orbit positions. It is a tricky thing to do but is possible with tine setting it up.

13-05-07, 01:45 PM	#3 (permalink)
lincsat Super-Dooper Moderator Join Date: Sep 2005 Location: In front of the PC Posts: 6,003 Thanks: 8 Thanked 2,580 Times in 667 Posts	Re: 2 lnb fixed dish It's quite easy. Set the prime LNB to the weaker satellite -19e or 13e then adjust the 2nd LNB until you find the 28e satellite. You can then use 2 downleads or a diseq switch to combine the feeds down 1 cable.