Setting up 4 lnbs

[pr1947]

Good morning,

Here is what I would like to do. I have a 90cm Ku dish and 4 single LNBFs. I do not have the lnb bracket/holder but this should not be an issue since I can purchase one locally or build one. I also have a DiSeqc switch. The Sat's I'm looking to set up are G-10 123, Echostar at 119, AMC 1 101 and IA 5 at 97. Where should the dish be positioned at? What would be the proper alignment for all 4 LNBFs? My location is latitude 26.6 N and longitude 80.5 W.

Thanks,

Jose

[Iceberg]

Highly unlikely you will be able to get those 4 with one dish. 97/101 or 123/119 is possible (I've done those) but 97 to 123 is too far away for a decent signal.

If you get a motor, that would solve the problem

[pr1947]

Iceberg,

I'm actually trying to set up 123, 119 and possibly 110 on a fixed dish. I'm more interested on those 3 Sat's. 97 W was a long shot anyway. I already have a motorized system. Right now I have the dish fixed on 123. Just need to know how to pick up both EchoStars if possible.

Thanks

[wejones]

Originally Posted by pr1947

Good morning,

Here is what I would like to do. I have a 90cm Ku dish and 4 single LNBFs. I do not have the lnb bracket/holder but this should not be an issue since I can purchase one locally or build one. I also have a DiSeqc switch. The Sat's I'm looking to set up are G-10 123, Echostar at 119, AMC 1 101 and IA 5 at 97. Where should the dish be positioned at? What would be the proper alignment for all 4 LNBFs? My location is latitude 26.6 N and longitude 80.5 W.

Thanks,

Jose

I know that there are web pages that say this kind of thing is possible, but I am really skeptical. Even if you can sucessfully aim the thing at these sats, I can guarantee that the reception on all sats will be significantly degraded. But the big problem I see is getting LNBFs close enough to look at sats separated by only 4 degrees. I think that the LNBFs would have to be about 1.4 inches apart at the centers, and I think the average lnbf has a bigger horn than that. There was an earlier suggestion saying that one lnbf could be closer to the dish, and it is possible that this could help, even though this likely means being at the wrong FL, however I'm still skeptical.
Also, from my mirror experiments, I have demonstrated to myself at least, that there is really only ONE focal point of a dish, and maybe not even one. So if you put more than one LNBF on a dish, only one can be at the focal point, and if you have widely spaced LNBFs like this, then NONE of the lnbfs are at the focal point. So reception will be significantly degraded.
I'm not saying it can't be done, as I trust experimentation more than theory, but I'm still waiting for reviews from people who have done this before beleiving it. And if anyone does it, I'd really like to hear a comparison of signal strength when compared to when the same dish was used with a single lnbf.

[elgemcdlf]

Install a Dish 500 dish. It has the lnbs spaced for 110 & 119

[pr1947]

Are you saying I can't get all three of them? I also have Dish 500 set up but I don't mess with that one. My wife won't let me.

[bobkat]

Originally Posted by wejones

But the big problem I see is getting LNBFs close enough to look at sats separated by only 4 degrees...

... and therein lies the infamous bottom line

Its tough getting a decent signal for two birds only 4 degrees apart. Like Iceberg I've done 97 and 101 on one dish but its tricky. It takes a lot of experimenting to find a pair of LNBs that will allow such close mounting -- actually they touch and I tie wrap them and caulk them together. Yes, focal distance is important too. I find that the old linear ExpressVu LNBs work great -- but they're getting real hard to find. Best to get a motor if you want that far a range of satellites.

kat

[elgemcdlf]

Originally Posted by pr1947

Are you saying I can't get all three of them? I also have Dish 500 set up but I don't mess with that one. My wife won't let me.

Would be far simpler to just use 2 dishes and one being motorized or even one motorized with an Invacom QPH-031 lnbf.

[Iceberg]

it is possible to do 123/119/110 on one dish. I did it a long time ago. 110 sucked but 123 worked great and 119 was 90+

123/119 is very easy to do and I use to do it until recently. I'll post a pic tonight as its on the computer at home

[Iceberg]

so I'm a day late (was doing a Dish install for someone)

as promised

1st pic is G10 & 119
2nd and 3rd was a 123/119/110 getup I did a couple years ago with hoseclamps

Dish aimed at 123 and got 119 nice and strong. Then added 110 later

last was a recent 123/119 setup

[wahroonga farm]

My experience, as for others, is that 4 degrees separation on an 85/90 cm standard parabolic dish, is too close, as lnbs will clash.

However the good news is that signals 10 degrees or more either side of centre are well within range. You'll lose 2-3dB at the 10deg plus mark, so depending on local EIRP's; it can work very well.

The best mounts are the metal fully adjustable 'magic mounts'. Not sure if Sadoun stocks them; have seen them from a Canadian supplier..

The focal length for multi-lnb doesn't really change (perhaps a bit closer in as you go out), but important to always point the lnb to the centre of the dish. This is to ensure that the LNB only 'sees' dish and doesn't pick up noise from beyond the rim of the dish.

To get 4 degree spacing you need to go up in dish size (draw yourself a few diagrams) or pick up a Triax dish (not sure if available in US). These seem, to have a natural elongated focal point even on the 65cm.

[pr1947]

Thanks Iceberg.

I'm going to attempt to set this up during the weekend. One thing I should ask, where should the dish be positioned at? 121 W....!!! Right now I have it at 123 W.

Thanks again.

[Iceberg]

aim the dish at 123 and add the LNB's from there. For 119, use zip ties to get the "eyes" right next to one another. That is the best for 123/119

DBS has more "play" than KU Band does for signal

[pr1947]

Thanks for the information Iceberg. I'll trop a line after I get done with it.