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Thread: Two LNBs on a 2.3m dish

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    Default Two LNBs on a 2.3m dish

    Hi All,
    Wish to install a 2.3m dish to get some C band channels. Couple of questions for the experts in here,

    How much maximum angle is possible between two C band LNBs on a 2.3m dish? I need 22.5 degrees! How to mount these on a single pole? Not thinking about motorizing.

    Is dual out C band LNBs available (not H and V) ? If yes where can I get them from? I have two points at home, one in the front living and the other in family living/dining.

    Cheers
    Tuxy



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    Do you mean 2 dishes on the one pole as the LNB is mounted on the dish not a pole and I have never seen a dual c band LNB but an F type splitter with do nicely.
    It's hard to make a come back when I havn't been anywhere
    I finally got my head together, now my bodies falling apart.
    為什麼不做你被塞滿

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    never seen a c band with 2 lnbf on it. i've seen them with 2 but one for H and 1 for V.... but its alot cheaper just to buy an actuator.

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    Senior Member Farmsky's Avatar
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    You can buy a 'dual' lnb for C-band. And they're cheap.

    It was first released by MTI and called the 'single cable' or 'one cable' solution. Available from . The trick is you'll need an stb that works with them. Strongs do (check your lnb types in the antenna setup page .... it's called OCS on a Strong).

    It works by frequency stacking H and V.

    You feed additional receivers by looping through each stb in a chain. You can do a whole village this way Or simply use a splitter.

    Now back to the two lnb set up. I feel 22.5 is probably stretching it a bit on C-band. It all depends on the actual satellites and signal strength (EIRP) and your location. You'd need the dish to be physically aligned to the exact midpoint between the two sats and then add the two 'offset' lnb's.

    What is your ruff location and which satellites?

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    I used to have 3 LNB's on my 1.8 mtr solid. AS3 AS4 and Apstar 6 (before Chinasat 6B) AS3 got me only the stronger signals.

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    Smile use an orthomode feed if you dont want a dual pol lnbf

    hi there,as the other post said you can use a dual polarity cband lnbf .i think there around $40.00 orso makesure the scaler rings are a good 1 there excellent for week signals but something like a zinwell or phoenix lnbf around 15k and up ,the orthomode feed is good especially on palapac2 as the vertical signals supposed to be aus wide its the satellite itself on the verical side its not right ,next year there replacing with a palapad2 or d1 i think it is hopefully they might get the verticals right this time but its not as bad as what happened to palapa b2ps replacement c1 also was at 113east but then the whole satellite died in the back side it !!was to do with the power supply and the batteries etc,.they sold it and renamed it anatolia 1 and it was used on ku band only ,thanks hamguy2 nsw

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    Hi hamguy2,

    I've got a bag of free

    Capitals ABCDE) ,

    full stops (.....) and

    paragraphs

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    Quote Originally Posted by Farmsky View Post
    Hi hamguy2,

    I've got a bag of free

    Capitals ABCDE) ,

    full stops (.....) and

    paragraphs
    LoL

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    do we really need capitals and full stops it just slows ones typing down but it may be handy for starting and finishing sentences as one tries to get ones point across while pa rousing the threads for points of interest as that is the whole point of being a member of austech and being involved in the satellite hobby i certainly enjoy sharing what i know and learning from others but if i dont take a breath soon i fear my lungs will implode
    It's hard to make a come back when I havn't been anywhere
    I finally got my head together, now my bodies falling apart.
    為什麼不做你被塞滿

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    Quote Originally Posted by MrElectricity View Post
    dowereallyneedcapitalsandfullstopsitjustslowsones typingdownbutitmaybehandyforstartingandfinishingse ntencesasonetriestogetones pointacrosswhileparousingthethreadsforpointsofinte restasthatisthewholepointof beingamemberofaustechandbeinginvolvedinthesatellit ehobbyicertainlyenjoysharingwhatiknowand learningfromothersbutifidonttakeabreathsoonifearmy lungswillimplode
    Why not go the whole hog.

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    nowyouarereallytalkingthatcertainlyisthespiritbuti treallyishardtoresistthetemptationtohitthespacebar
    It's hard to make a come back when I havn't been anywhere
    I finally got my head together, now my bodies falling apart.
    為什麼不做你被塞滿

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    Thanks for the shocking piece of engineering Mr.electricity! I have seen a couple of LNBs on a 12feet dish before, but never ever imagined to go this far.
    I still doubt the viability of a complex setup on a small dish like the 8feet (2.3m) ones. Is the single cable dual LNBs supported by relooks/mutants/DMs? Is it possible to adjust the angle between the two blocks? I thought these are suitable for birds reside close by. I need minimum 22.5 degrees of separation. May not be an issue if I can swing one on its axis perpendicular to the feed pole and along the Clark's belt. Unfortunately I haven't seen such an LNB before.
    Attached is a sketch for the setup I have in mind. I have the two Ku band 65cm dishes working at the moment.

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    Senior Member Farmsky's Avatar
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    If you want to understand the losses involved with multi-lnb have a look at this graph.



    This is for a moderately large commercial dish, however it pretty well matches what we see with small consumer dishes.

    As advised earlier, it all depends where you are and what sats you wish to view. It all comes down to how much EIRP the satellites put down on the ground in your backyard, as to whether it will work.

    I don't know if single cable LNBs are supported by Relooks, Mutants or DMs.

    BTW the lnb (satellite) separation for multi-lnb is not the difference in degrees of longitude for the satellites location over the equator. It is the trigonometrical sum of the difference of the Az and El of both birds in degrees for your location. This measurement would only closely approximate the sats longitude at the equator, if you lived on the equator and were interested in satellites directly overhead.

    Here's my crude graphic of how multi-lnb works.


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    Great post Farmsky.

    Considering the loss of signal, have you thought about installing a actuator and positioner?

    Is your dish on a polar mount?

    No loss of signal and all the cband sats over your head, not too hard to do and not that expensive also.

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    Mr Electricity, nice pix you gotta it here. Mesh, Hmm . . . Solid dish is my cup of tea.

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    Quote Originally Posted by Chanceforlove View Post
    Mr Electricity, nice pix you gotta it here. Mesh, Hmm . . . Solid dish is my cup of tea.

    Till you get some really big winds Lol

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    Quote Originally Posted by Godzilla View Post
    Till you get some really big winds Lol
    Not my problem, not my dish
    It's hard to make a come back when I havn't been anywhere
    I finally got my head together, now my bodies falling apart.
    為什麼不做你被塞滿

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    Yeh sat behind one of these multi lnbf dish 3+ meter on c band as an educated observer, in phillipines on dreamtv an such measat,agila etc. % levels were shit! High incline levels. should have been easy asia equit. sats.
    90+% on one,next less than 10degree to the next,signal drop to bellow 47% for lock on a Dynasat rx for nagra encrypt an fta etc. SKew up the shit a bit I though !but couldnt mess with it,myself..
    Here in Oz,get yourself a actuator an positioner control box,eg vbox.an some local who is tuned up on c band installs.forget the multi lnbf ,experts only!an patience/labour? Cheers!

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