Multi LNB questions

[SATire]

I am getting the parts together to set up a multi lnb setup.
The birds I want to pick up will be 83W, 89W, 97W and 103W.
I won't know if I can see as far East as 83W until I get the dish mounted but right now, that's the plan.

To start with, I am;
Latitude: 45.1367°
Longitude: -92.9900°
91W is my due South point.

Dish setup suggestions are;
Elevation: 38.0°
Azimuth (true): 177.2°
Azimuth (magn.): 176.9°
LNB Skew [?]: -2.0°

Based on the above, in order to get multiple lnb's going, I am guessing that I need to face the dish to some central point of the four satellites I want to pick up and not the starting points I've used above when I set up my single lnb dish.

Mike

 

[Mr Tony]

actually 93 is your true south

As for picking up those 4 on the same dish, honestly unless its a Toroidal dish, those 4 probably wont happen

I've been able to get 89,93,97,103 on a 36" dish. The ends were real low signal but I wanted Pentagon (on 103...no longer there) and ABC News Now on 89W

 

[Magic Static]

Hard to do with FTA sats. I set up a dish with 4 lbs with a 29.5° spread made from a DTV triple pan. I could get readable signal from DBS sats. But FTA won't happen that easy.
To answer the question on the alignment of your proposed dish. Set it to 93° numbers wise.

 

[Keith Brannen]

It is possible, if you aim the LNB arm at 93, then the outermost satellites would be 10 degrees off-centre (which is a bit farther than the 6 to 8 degrees that is normally optimal). For 83 (and RTV) it might be good enough, it is a fairly strong transponder, though not the strongest. However, if you are trying for the NBC muxes on 103, I am fairly certain it won't work. I barely got them (and only two of the three muxes) when I had the LNB 6 degrees off-centre on my 80cm. I eventually moved 97 off-centre a bit, just to get 103 a bit closer to centre to gain a valuable few percentages. Now I get just a hint every now and again of the third transponder. They definitely require a lot of signal!

When I had the dish pointed at 97, I did go out to 87 at one time, and did get most, but not all signals (and some were very weak at that distance). It was good enough at the time for what I wanted.

Anyhow, the best thing to do is set it up as you would like, see what you can get, and adjust accordingly.

 

[SATire]

>To answer the question on the alignment of your proposed dish. Set it to 93°
>numbers wise.

Ok, so I have a starting point at least. I'm just concerned that now I've wasted money on the wrong dish and should get another one instead of bothering with this one... which just happens to have come in this morning <sigh>.

 

[SATire]

>It is possible, if you aim the LNB arm at 93, then the outermost satellites would be 10 degrees off-centre (which is a bit farther
>than the 6 to 8 degrees that is normally optimal). For 83 (and RTV) it might be good enough, it is a fairly strong transponder,

I never really thought about the spread either. I just looked around for a multi lnb bracket that said it seemed able to do what I wanted.

4 LNB BRACKET/4 LNB HOLDER DISH NETWORK FTA SATELLITE | eBay

>though not the strongest. However, if you are trying for the NBC muxes on 103, I am fairly certain it won't work.
>I barely got them (and only two of the three muxes) when I had the LNB 6 degrees off-centre on my 80cm.

More than anything, I just want 97W fixed and which ever bird has the most live news channels which seems to be 83W or 89W, can't recall at the moment.

 

[SATire]

If I am better off to get a different dish, this one is new in the box before I open it meaning I could at least resell it.

 

[Magic Static]

You never mentioned what dish you were using. 36"?

 

[SATire]

>actually 93 is your true south

Weird, I replied to this but my reply is gone.
Anyhow, ya, you're right, I meant 93W.

>As for picking up those 4 on the same dish, honestly unless its a Toroidal
>dish, those 4 probably wont happen

No one mentioned that in the other thread so I went ahead and bought a simple round but larger dish.

I'll take what ever I can get. I just want a fixed setup for 97 and some of the live news feeds.

 

[SATire]

You never mentioned what dish you were using. 36"?

Sorry my post got lost somewhere. There was a burp with this site yesterday, everything was gone for a short while.
I know I posted it but here it is again. It's a round 39". Just like this one.

39 SATELLITE FREE TV KU BAND DISH ANTENNA 36 33 FTA LNB | eBay

 

[Magic Static]

I would give it a shot. Any larger dish will be very expensive to ship. Your not out a lot if it doesn't work. But that dish looks just like the WSI9036 and not marked for adjustment very well. And you cant' skew the dish like a multi-lnb dish.

 

[SATire]

>And you cant' skew the dish like a multi-lnb dish.

Damn, another thing I didn't think about.
I still have this perfectly good Starband dish up there, it does some of these things. It's not 39" though.

 

[Keith Brannen]

39" will work well for multiple LNBs (after all, I use 80cm and less, with good success).

The only concern I have is with the LNB bracket, as the LNB holder base of the bracket is a straight line and not curved, so will not conform to the optimal focal distance of the satellites on the dish, especially for satellites at the extreme ends of the bracket (would work fine for the strong circular satellites, where there is so much signal, a little loss is not so important as it is on linear). The problem with it (and I have used them myself, in a modifed form) is the lack of being able to move the LNB closer to the dish to get in that curved focal line.

Therefore, I would suggest satellites that are close to the centre (6-8 degrees) so as not too lose too much because of the lack of adjustment towards the dish (other than pushing the LNB as far forward as possible in the LNB holder). For example, 89, 97 (at centre) and 103.

Like I said, set it up and experiment!

 

[SATire]

The bracket was very cheap, I could always order up a better one.

 

[Keith Brannen]

>And you cant' skew the dish like a multi-lnb dish.

Damn, another thing I didn't think about.
I still have this perfectly good Starband dish up there, it does some of these things. It's not 39" though.

Since you are close to the top of the arc with these satellites, your adjustments up and down will be slight, and other than my 75e and 60e dishes, all others are "round" dishes and I've had good success across the arc. The advantage of a skewable (elliptical) dish is that you can place LNBs farther away from the centre of the dish and not experience as much loss as on a "round" dish. But when you are talking about 6 to 8 degrees off-centre, the loss will be minimal, especially when you are close to the top of the arc.

 

[Keith Brannen]

The bracket was very cheap, I could always order up a better one.

Give it a try first, if you don't like it, or can't make enough adjustments, then you could always get another one.

 

[pendragon]

If you want to guarantee success, pick up a toroid dish like the Wave Frontier T90. I have three. Getting +/-10 degrees from one of these is easy and +/-20 degrees is practical. They're not that much larger than a single 36-39" dish, and once set up it's ridiculously easy to add satellites or move the LNBs to different positions without adjusting the dish. Shipping to your doorstep can be expensive, but every time I ordered one you could pick it up at a shipping depot and save most of that cost.

 

[oceansatellite]

I am getting the parts together to set up a multi lnb setup.
The birds I want to pick up will be 83W, 89W, 97W and 103W.
I won't know if I can see as far East as 83W until I get the dish mounted but right now, that's the plan.

To start with, I am;
Latitude: 45.1367°
Longitude: -92.9900°
91W is my due South point.

Dish setup suggestions are;
Elevation: 38.0°
Azimuth (true): 177.2°
Azimuth (magn.): 176.9°
LNB Skew [?]: -2.0°

Based on the above, in order to get multiple lnb's going, I am guessing that I need to face the dish to some central point of the four satellites I want to pick up and not the starting points I've used above when I set up my single lnb dish.

Mike

Your going to have a hard time with Retro TV on 83 w if it's off from center quite a bit. That is a tough transponder to catch


here are two of my setups, just to let it known it can be done (both of these are four footers)


89w, 95w. 97w, 101w, 103w

and

72w, 74w. 79w 83w 87w and 91w


I get about 57% on the NBC mux on 72w and Retro TV is 68%. (83w is centered)

Last word of advice I have for you is a 120cm will help you quite a bit

 

[Anole]

The bracket was very cheap, I could always order up a better one.

Members here have fabricated all sorts of mounts, brackets, and holders.
We also have a thread where one of the members did some math to locate the LNBF for height 'n horizontal position.
(but not depth [in/out])
I'm sure you can find plenty of good ideas on the forum.

 

[SATire]

>And you cant' skew the dish like a multi-lnb dish.

My old thread was;
404 - Whoops Page Not Found
and now this is the new one. Guessing it's just forum software updates.

Anyways...

I'll pull the old dish down tomorrow. There is a chance I might be able to fabricate something up which would allow the new dish to skew.