Advice Needed Homemade 2 dish array

[Llorx]

Hi,

Recently I installed the typical Internet Satellite system in my house. One dish, coaxial cable, one modem and a computer. I liked the idea of having direct connection to a satellite some thousands of km away and want to play around with that.

I have access to a second dish with LNB, and I would like to know how can I have a fully functional array connected to the same modem, being this way: 2 dishes, 2 LNB, 2 coaxial cables coming from the LNBs connected to a splitter, and one cable coming from the splitter to the modem.

I'm pretty sure that is not that way how it has to be done (sound easy, and surely that won't be easy).

I have read something about phase matching, and that depending of the wavelength, there's an optimal cable distance, and also that the 2 cables connected to the splitter need to have the same distance.

Has someone done this before? have experience or knowledge about this? I'm entering in a pretty complicated world? Some light about this will be really helpful.

 

[timo_w2s]

I don't believe it's possible on normal consumer grade kit otherwise we'd all be doing it on this forum. Phase matching is the problem. Would be great if it where possible though.

 

[Llorx]

I see... And you know a system to increase the signal apart from increasing the dish size? I've also tried to point 2 dishes to one LNB, but that's really really difficult.

 

[archive10]

At these price-levels, dish size is by far the best option.
Only real alternative is relocation, but that tends to be more trouble than getting bigger dish...

Some people have experimented with (super-) cooling of LNB to minimize electronics-induced noise, but you will need a fairly elaborate set-up, and a heavily modified LNB to support continued out-door use.
And IIRC you get up to a dB or so more S/N. An 1.8m gives you 4 db better S/N compard to a 1.2m dish.

(But perhaps a project for the DirectTV LNB-modding bunch once they tire of their Ka-band explorations? Maybe use some of the cryo-equipment used made affordable by PC-overclockers?)

 

[davemurgtroyd]

I see... And you know a system to increase the signal apart from increasing the dish size? I've also tried to point 2 dishes to one LNB, but that's really really difficult.

Whichever way you attempt this 2 dishes and/or two lnbs you will find it impossible with equipment available on the domestic market. Lnbs are only designed to accept signal from a particular viewing "cone" which is usually the size of the dish they are aligned on so there is no way to align the lnb on two dishes without losing a significant amount of both dishes reflected signal and it would also be next to impossible to correctly illuminate the lnb at both dishes focal point.

There is only one way to get more signal a larger or more efficient dish.

 

[Llorx]

Perfect. Thank you for your replies guys. Going to invest in a bigger dish then.

So, investing in a bigger dish, must I change the length of the arm (I don't know how to call it xD), or having the same length I will notice the signal increase? Is there any arm length/dish size/effciency rule for this (because of the viewing "cone", perhaps)? My current dish size is about 75cm, and I want to invest in a 120cm dish. The position is off-axis, exactly like this: http://www.toowayblog.co.uk/uploads/2011/06/100611-Tooway-kit-640x550.jpg

 

[archive10]

Perfect. Thank you for your replies guys. Going to invest in a bigger dish then.

So, investing in a bigger dish, must I change the length of the arm (I don't know how to call it xD), or having the same length I will notice the signal increase? Is there any arm length/dish size/effciency rule for this (because of the viewing "cone", perhaps)? My current dish size is about 75cm, and I want to invest in a 120cm dish. The position is off-axis, exactly like this: http://www.toowayblog.co.uk/uploads/2011/06/100611-Tooway-kit-640x550.jpg

The feed-holding arm comes with, and is specific to, the dish. You can't just change the reflector.
You will be hard pressed to buy the dish without the arm, in fact...

As you are using your Tooway dish for Rx/Tx data-link (and I suppose that the dish in principle still belongs to Tooway), you will be best off getting a complete separate 120cm dish for TV reception purposes.
The Rx/Tx LNB assembly is likely to be very heavy, and putting that + a couple of extra LNBs on a normal steel-dish will put a strain on the dish. This is not good for performance or structural integrity.
If you really wanted to put the Rx/Tx on a 120 cm dish, you can buy a semi-pro dish (as in the Channel Master 120 with a metal feed holder or even heavy-duty feed-arm configuration), but this is quite costly compared to just getting a 120cm dish, popping an LNB on it, and sticking on the wall NeXT the tooway dish.

 

[Llorx]

No, the dish is mine. I bought the entire equip instead of renting it. I can disassemble it as I want.

The LNB is a bit heavy, yes, so I think that I'm going to buy a cheap second hand dish with a cheap arm and attach my own tensioners before buying a 450€ dish.

Thank you for everything, you were really helpful! :-)

 

[timo_w2s]

Forgive me if this is a silly question, but what advantage would a larger dish have for sat internet? Isn't your current size OK for Spain? Why not keep the current dish for internet and get another larger dish for TV, then you don't need to worry about heavy BUC/LNBs.

 

[Llorx]

Because I'm heading in making a portable dish to move it around my country, so I want the maximize signal to achieve a connection in the worse scenario that can happen. I can't imagine it, but just in case.

I've already mounted the second dish in a tripod and successfully had a connection, but I don't know how it is going to work in the other side of my country. Maybe if I have to put it behind a tree or in between beam spots (Tooway works with beam spots).