LNB Bracket for Prime Focus

[kishray]

Hello Everyone,
I am living in the southern caribbean and I have a 10 ft solid dish on 119 and another 12 ft on 61.5. I am having great reception but I would like to know if there are any lnb brackets out there that I can find that I can use to to pick up multiple satellite on my prime focus dishes. If not, are there any documents or diagrams that can give me the distance so that I can have the bracket made myself. I have tried google to see what I can find but I was unable to find anything. I am intrested in a bracket that can pick up 110, 118 and 119 on one of the prime focuss and 61.5 and 72.7 on the other dish. Any help would be greatly appreciated. Thanks in advance.

kishray.

[hondoharry]

Those big round dishes hone in on the sat like a telescope making it very difficult to pick up good signal on more than one sat, though I did see a 6 ft. dish on 119 with a jury rigged LNB on 110 getting a few TP's. You can hold an LNB in your hand to find the best position but I doubt you'll get anything. For multiple sats the dish should be oval, not round.

[kishray]

Thanks hondoharry for your advise and taking the time out to respond. I really appreciate your input.

[jvvh5897]

For multiple sats the dish should be oval, not round.

While the offset dishes do better in some things, like keeping the shadow of the LNB from interfering with signal reaching the dish, they are just a section cut from a full prime focus dish as far as the math is concerned. If offset dishes can get offaxis signals, then prime focus dishes can too. If you do some ray tracing of how dishes work you will see that.

Now, getting the LNB to the right spot on a prime focus dish can be a real pain, and the extra LNBs will shadow part of the dish and so cut down on signal, but you could do it.

[kishray]

Thanks jvvh5897 for your input. I really appreciate you taking the time out to share your views and your opinion. I thought there would of been an easier way of doing this mathematically and also there were brackets already made for the prime focus dish to recieve multiple satellite. I would not bother going through the pain after what i read above. Thanks once again everyone for there time and your assistance.

[hondoharry]

If a prime has the same math as offset, couldn't a prime be adapted to offset with legs/holder from an offset dish? They sell them separate. Offset is said to capture significantly more signal for DTH TV.

[kishray]

Hello hondoharry,
Thanks for you input. I really appreciate it. Do you have any pics that I can get an idea or any information on how this can be done? Thanks in advance.

[hondoharry]

Hello hondoharry,
Thanks for you input. I really appreciate it. Do you have any pics that I can get an idea or any information on how this can be done? Thanks in advance.

I have no idea if it can be done. I'd try Google.

[kishray]

Hello hondoharry,
I tried googling it as well without no luck. Thanks once again for taking time out for reading my post and making/ commenting on it also. I really appreciate it. Take care.

[Terryl]

Well trying to redesign the dish to do something it was not ment to do will be difficult, but with some good engineering skills and a bit of luck you might get it to work.

A prime focus dish was designed to do one thing, look at a signle satellite, and some may have a problem as some do not have a way to skew the additional LNB's.

This is because most use a single LNB mount that will let the LNB it's self be skewed to align it to the horizontal and vertical transponders on the satellite.

When adding more then the one LNB to a prime focus dish you could come across this problem, so to compensate you have to skew the new multi LNB bracket, or use a multi LNB bracket that will allow you to adjust the LNB's to different levels on the bracket.

See all the geosynchronous satellites up there in the Clark belt are not in a straight line across the sky, but in a very big arc, and this arc will not be the same for all locations.

So you see that trying to use a dish designed for one satellite that you may have some fun times trying to set it up.

This is why they came out with the elliptical dish, it has a border receive beamwith, is designed for more then one satellite, and the LNB's can be set up in a straight line on a bracket designed with the correct spacing, then the dish it's self can be skewed to line the LNB's up with the arc of the Clark belt.


But with that said, go have some fun in trying things out, this is what testing is all about.

[kishray]

Hello Terryl,
Thank you for taking time out to comment on the posting. Your post was a very imformative post and also for giving us a clearer understanding of the different setup and how satellite dish works. We really appreciate it. I think I would be wasting my time trying to find and make a multiple satellite lnb bracket to work on the prime focus dish after what I just read above in your post. Thank you once again.