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Auto Satellite Dish Repairs .. .. .. maybe .. .

Discussion in 'Radio and Communications' started by Musicmanager, Jul 9, 2017.

  1. Musicmanager

    Musicmanager Active Member

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    Hi Les

    Thanks for the information and advice .. .. .. .

    The set-top box has it's own power supply from mains 240v ( presumably some sort of PSU inside )

    I did see the Axing TZU 15-02 Power Inserter amongst many others I looked at but I was put off by the rating marks .. .. it's marked 65v @ 1amp .. if that's an absolute max. rating there's no problem; but if not 12v might not be enough to drive it ?

    That won't be a problem, during the quest I think I've gained stock of every type of F connector known to human kind !

    Thanks again

    S
     
  2. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    I'm somewhat bemused by it all :D

    Satellite LNB's are normally powered direct from the receiver, and commonly incorporate polarity and band-switching by various devious methods.

    Assuming there's no power (or signalling controls) from the receiver, then a 'power inserter' is just an RF choke and the relevant connectors. Nothing special or complicated, 1mH (or smaller) would be fine - I've always used any random RF choke I've found on an old PCB, never worried about the value.
     
  3. Musicmanager

    Musicmanager Active Member

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    Perhaps watching this will give you less bemusement .. ..

    The issue is not powering the LNB, but powering the two motors used to position the dish.

    S
     
  4. dave

    Dave New Member

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  5. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Nope, no less bemused :D

    It's powering the LNB as well, and steering a dish up the LNB feed coax is a common technique, usually using DiSEqC:

    https://en.wikipedia.org/wiki/DiSEqC

    Presumably your dish is doing something similar?, as it uses nothing but a single coaxial feed.
     
  6. Musicmanager

    Musicmanager Active Member

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    I think that's where I started this morning . I'm not sure !

    I'm familiar with DISEqC in various forms but .. .. .. .. The Receiver connected direct to the dish does not provide sufficient power to move the positioning motors; The picture I attached this morning clearly shows a separate plug in power supply which is present in the kit I have; There are several You Tube demos of PAPSA set up and on some of them the operator clearly powers the dish with the power inserter but with the receiver disconnected, which is then connected after correct positioning; what isn't clear is the possible disconnection of the power supply at that point.

    This particular PAPSA version is preset to Astra 2 so the DISEqC may be installed within the dish circuitry.

    S
     
  7. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Assuming that the dish is powered, without the receiver (to position it), and then the feed is swapped to the receiver itself, then all should be well.

    However, what kind of receiver are you using? - 28.2E (Astra 2) is the position used by Sky - and receivers (either Sky or Freesat) almost exclusively use the Sky style LNB's, which may be totally different to what is fitted on that dish.
     
  8. Musicmanager

    Musicmanager Active Member

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    Great ! I'll rig something up and give that a try .. .. TY

    I don't think that will be a problem .. ..although not marketed in the UK now, the original brochure is still on the net, indeed, the picture I posted earlier is from that brochure. The narrative in that brochure talks about being able to receive all UK TV channels using a receiver of your choice and one of the pictures shows the dish connected to a old style Sky Box.

    Still, I now know of a good way to find out !

    Thanks for your help .. .. .

    S
     
  9. Les Jones

    Les Jones Well-Known Member

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    I have had some more thoughts on the power inserter. It is not as simple as just inserting the 12 volt power. A normal satellite receiver switches between horizontal and vertical polorisation by changing the LNB voltage from about 13 volts to about 18 volts. It also switches between two local oscillator frequencies in the LNB by inserting a 22 Khz signal into the coax to the LNB. The 22 Khz could be passed though the power inserter but it would require an extra filter in the power feed to prevent the 22 Khz signal being shorted out. The polorisation control would require extra circuitry to convert the change from 13 to 18 volts from the receiver to some other signal to be sent to the dish control unit. So my suggestion of using a masthead amplifier power inserter would not work.

    Les.
     
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  10. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    That's a description of how old Sky (and Freesat) boxes in the UK work, it isn't the only type of LNB though - although as the unit in question only has a single connection to it, it's presumably so.

    The new SkyQ boxes use an entirely new and different LNB, but that's not really relevant here.
     
  11. Musicmanager

    Musicmanager Active Member

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    Just an ... ... 'and finally .. ... '

    I managed to get my hands on an OEM Power Inserter .. .. .. .so like all good inquisitive little sods, I took the back off for a looksee !

    PAPSA Power Inserter.JPG

    I suspect this will make more sense to some of you guys than it did to me, but the bottom line is it all works now !

    Thanks for your help Guys .. .. ..

    S
     
  12. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Notice the inductor at the left, that's the working part :D
     
  13. Musicmanager

    Musicmanager Active Member

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    I knew that Nigel, Honest !! :)

    S
     

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