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Thread: C-Band LNB for an offset dish

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    Default C-Band LNB for an offset dish

    Hey guys,

    I am considering taking ownership of an old 1.2 m Channel Master offset dish that was used for a VSAT setup.

    The signal I wish to pick up is what I reckon to be reasonably strong for C-band, at least I think -- 41.5 dBW, for which I would apparently need a 90-115cm dish.

    It is DVB-S with an FEC of 3/4, but there are some DVB-S2 signals I also want to tune into.

    I was wondering what sort of C-band LNB would I be able to use in such a setup? Have any of you guys used such a relatively small offset dish with C-band?

    The signals are circularly polarised too, so it would have to be a circular LNB.

    TIA



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    I see this sort of thing on the web:



    Do the LNBs generally come with these scalar rings or do I have to get them separately?

    And, do they also have issues with different size throats, etc. like you get with the Ku-band ones, so that it causes the problem of the LNB won't fit in the bracket of that particular make of dish?

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    yep thats the sort that you want they are dual band (c&ku) lots to see with it go for it
    . Please treat people as you would like to be treated yourself.

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    Quote Originally Posted by Dr_Mohs View Post
    I see this sort of thing on the web:



    Do the LNBs generally come with these scalar rings or do I have to get them separately?

    And, do they also have issues with different size throats, etc. like you get with the Ku-band ones, so that it causes the problem of the LNB won't fit in the bracket of that particular make of dish?
    they are sold separate . use a Standard C-Band LNB-F and offset scalar ring I have some of the scalar rings (New) in the shed with mount to fit a offset dish if you want one free (just pay post) you are more than welcome to one .

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    Bit of a bummer guys...I think the guy doesn't want to sell the dish anymore.

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    Sounds like the thread is at a dead end then... if you can't proceed, but to answer the questions:

    You would need a C-band LNB with an elliptical scalar ring.

    As you are aware, the majority of C-band dishes are prime-focus... round.

    A prime-focus LNB expects to 'see' a round dish, so when you put one on an elliptical offset dish, that view of the dish surface typically looks beyond the shorter edges, particularly increasing the likelihood of picking up noise.

    Getting the correct focal distance can also vary, compared to the mounting position of a Ku-band LNB the dish was designed to work with.

    Sure, it's possible to use a bog-standard C-band prime-focus LNB on an offset dish, but the performance is a compromise.

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    Quote Originally Posted by mtv View Post
    ...that view of the dish surface typically looks beyond the shorter edges, particularly increasing the likelihood of picking up noise.

    Getting the correct focal distance can also vary, compared to the mounting position of a Ku-band LNB the dish was designed to work with.

    Sure, it's possible to use a bog-standard C-band prime-focus LNB on an offset dish, but the performance is a compromise.
    Yeah, that's what worried me. I see a lot of C-band LNBs being advertised here locally, but I can see they are all meant for prime-focus. I don't want to buy something I wasn't supposed to.

    Those scalar rings in the picture I uploaded -- they are not the elliptical ones required, are they? They look perfectly circular to me.

    Edit: Also, would this dish size be big enough for a properly strong, locked signal at that EIRP level? DVB-S2 is normally a bit more sensitive than DVB-S, not so? (needs a bigger dish preferably, etc.)

    Does one still also get the problem that the LNB, relatively, may be too large in size for the dish? I know this is sometimes more an issue with a smaller prime-focus, where the LNB physically blocks out some of the signal, but since this dish is offset, the signal misses the LNB. What I mean is, it is OK to install a fairly large-sized LNB with an offset dish? Some C-band LNBs seem quite large in size.

    If it's OK with you guys, I'd like to still keep this thread going a little while to find out a bit more, even though this opportunity appears to have gone past. I admit, I am very unfamiliar with setting up a C-band dish (but curious), Ku-band offset is not exactly very difficult by comparison. One of the reasons is that most of the C-band stuff we get on this side of the world usually requires something like a 3.5+ m BUD/mesh job or similar, because of the signals being fairly weak. Never had the space or time to play with something like that, so admittedly C-band is not my strong point.

    Thanks for all the input so far!
    Last edited by irritant; 19-05-19 at 12:21 AM.

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    Thanks for all the info guys!

    I now have more than enough to keep me busy. Much appreciated.

    Thanks MTV, you can go ahead and close the thread.

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    I use a 1.8M Prodelin offset dish for Intelsat 19 Cband and it works very good on all transpoders.
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    Sorry guys but just keeping this thread going a little longer!!!

    I have a 1.2m Azure Shine dish with a standard KU lnb on the end of it. I am getting very good reception of the nine network on Intelsat 19 KU so my question is...................Would I get any C band reception with a dual C/KU LNB - or should I just sit back and enjoy the nine network and forget about getting any sort of C band reception as well?

    Thanks in advance!

    With my 3.7m C band dish I am not getting anything of Intelsat 19 because of a large tree!!!

    Regards.

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    Quote Originally Posted by David071 View Post
    I have a 1.2m Azure Shine dish ... Would I get any C band reception with a dual C/KU LNB - or should I just sit back and enjoy the nine network and forget about getting any sort of C band reception as well?
    I have not used a dual C/Ku LNB but would think that performance on both would be negatively impacted compared to individual LNBs. Leroy where are you?

    If you are happy with the Ku stick with it.

    Having said that I had a separate 1.2m dish with C band LNB/standard scalar rings on, as far as I can remember, Asiasat 7 at 105.5E and was happy with what I could receive.
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    Quote Originally Posted by David071 View Post
    Sorry guys but just keeping this thread going a little longer!!!

    I have a 1.2m Azure Shine dish with a standard KU lnb on the end of it. I am getting very good reception of the nine network on Intelsat 19 KU so my question is...................Would I get any C band reception with a dual C/KU LNB - or should I just sit back and enjoy the nine network and forget about getting any sort of C band reception as well?

    Thanks in advance!

    With my 3.7m C band dish I am not getting anything of Intelsat 19 because of a large tree!!!

    Regards.
    Me thinks that the 1.2 OFFSET would be too small for CBand on Intelsat 19. Even a cheap 2.3M prime Focus would get Intelsat 19 CBand
    Not responsible for any post written after the 28/10/2014. My pet hate, Corrupt Politicians, Corrupt Legal System + a legal system Australia wide that does not allow you to sue a Solicitor or Barrister for Professional Negligence (as Stated by the Law Society and prominent Lawyers) and Corrupt Cops. Not necessarily in this order. Please Note Lawyers are PROTECTED SPECIES IN THIS COUNTRY, PROTECTED FROM THEIR F..K UPS

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    Quote Originally Posted by Dr_Mohs View Post
    The signals are circularly polarised too, so it would have to be a circular LNB.

    TIA
    If you end up using a linear LNBF instead of circular, remember you will lose 3dB which means you will need a bigger dish.

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