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Thread: DIY Power inserter

  1. #16
    adm's Avatar
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    Quote Originally Posted by CRMS View Post
    Just tried a GigaBlue Unicable LNB - 24 SCR, 2 Legacy.
    Signal strengths - Unicable SNR 98/99%, AGC 8%, 16.0dB. Legacy SNR 99% AGC 97% 16.0 dB. Went through the Tuner set up correctly - I think. Signal strengths are better than elderly Universal LNB. So interesting that Unicable AGC is 8% and Legacy 97%.
    Unicable is complete rubbish with continual "Tune Failed". Legacy is fine.
    So tried power injection with 11.9v at the LNB. No signal at all?? Odd, so I'll bump up the voltage to 20v and see if that makes a difference.
    Otherwise, grateful for any pointers??
    Inserters with matching power supplies from other manufactures of unicable II LNBs suggest a 19V supply voltage.

    Into which downlead are you injecting the power? It should be the unicable output and not the legacy.
    When injecting power via an inserter is there a facility to stop the box also providing power to the LNB - the two power sources could be fighting each other?
    How much current can your external power module supply - the spec suggests 300mA for the unicable side of the LNB ?
    Xtrend ET10K, 2 x satellite tuners 28.2 (UK Freesat channels), 2 x hybrid (UK Freeview channels)

  2. #17
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    Quote Originally Posted by Huevos View Post
    Also, if you are using a power pass splitter it should be diode protected so voltage from one STB cannot arrive at the aerial socket of another that shares the same LNB. i.e. the voltage can only flow from the STB to the LNB but not in the opposite direction... and the STB itself should also have diode protection at the socket to prevent external voltage from entering it.
    I assume that the STBs are already internally diode protected if by design they all can produce the unicable power to common down lead. It makes sense that the STBs all produce power because one or more boxes connected to a common down-lead (via splitters) could be switched off and the LNB still has to get its power from one of the STBs still switched on. The individual STBs don't know when someone is going to switch off another box on the cable.

    The important part of your statement is that the power inserter must also have diode blocking on the power supply input because without a diode a power supply with a low source impedance would instantly drag down the voltage output from any STB if the external power supply was set to a voltage below what the STB would output itself. By design I would expect the STB to also be protected by current limiting its own output to what it sees as a virtual short circuit.

    One question for my own education
    In a unicable tuner mode do the STB boxes with multiple satellite input sockets produce the voltage on all these socket inputs all the time when the box is switched on or only when a tuner (or tuners connected to the socket by various internal means) is required for watching/recording?


    With regards the DIY hacked power inserter mentioned elsewhere in this thread. It was not put forward on Satcure site as an alternative supply for unicable LNBs but more for getting power for other purposes such as providing power to a remote control extender (magic eye) or a head end amplifier on a terrestrial aerial system where the typically 5V from the terrestrial box could be switched off and 12V supplied from an external source . Note that the DIY solution doesn’t show F plugs but Belling Lee type connectors used for terrestrial TV. A hack designed for one purpose doesn’t necessarily work for different systems.
    Xtrend ET10K, 2 x satellite tuners 28.2 (UK Freesat channels), 2 x hybrid (UK Freeview channels)

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  4. #18

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    Quote Originally Posted by twol View Post
    Post tuner setup
    Right had a another fiddle.
    Satcure DIY DC power injector and 19.5v at Gigablue Unicable 2 LNB. When I last looked WoS didn't have any injectors but see them now in stock.
    SNR 100%, AGC 7% and 16.4 dB. Don't think I can get better than that.

    Tuner A

    Unicable04.jpg

    Tuner B to H as H. Each Tuner has own Channel, starting with Channel 1 for Tuner A to 8 for H.

    Unicable01.jpg

    Slight blank screen on Channel change.

    Tried Tuner B equal to A, but CrossEPG wouldn't download - "CrossEPG error. Timeout for Tuner lock".

    Now set 8 recordings and get picture break up and "Tune fail".

    Perhaps as suggested in other posts, I should split signal to Tuner A and B and feed 3 FBC off each??
    Attached Images Attached Images

  5. #19
    adm's Avatar
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    Quote Originally Posted by CRMS View Post

    Now set 8 recordings and get picture break up and "Tune fail".
    Could this now be down to the quality of the cables you are using or the integrity of the cable now that you have cut into it to hack a power source? With unicable you asking more of the cable than with a TV aerial or a traditional LNB. Are you using a CT100/WF100 type cable with a full copper screen + screen braiding?

    A hack into the cable may mean its no longer got a characteristic 75 ohm impedance and you are now getting reflections.

    Code:
    https://en.wikipedia.org/wiki/Signal_reflection
    
    https://www.youtube.com/watch?v=zrDxSM91Jcg
    Last edited by adm; 23-07-20 at 00:00.
    Xtrend ET10K, 2 x satellite tuners 28.2 (UK Freesat channels), 2 x hybrid (UK Freeview channels)

  6. #20

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    Cable is OK - copper braid, alu wrap, air core. Would have thought VSWR could be incorporated into software?? - my marine AIS receiver has a VSWR read out.

    Now split the cable after the power injector to feed Tuner A and B - might as well use both of them as I've paid for them!! And 3 FBC tuners off each. Much better. SNR 99%, AGC 5% and 16 dB on both tuners.
    8 channels merrily recording.

  7. #21
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    Quote Originally Posted by CRMS View Post
    Cable is OK - copper braid, alu wrap, air core. Would have thought VSWR could be incorporated into software?? - my marine AIS receiver has a VSWR read out.
    I don't see how it can unless it transmits as well as receiving.
    Zgemma H7S, 2 x single 28.2E, 1 x Freeview Hannington. Running OpenVIX (normally latest stable) with "Magic-FHD" skin.

  8. #22

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    Well fitted the V5-033 device with 19.5v DC going up to the LNB, green LED lit, and other end to the receiver.
    https://vision-products.co.uk/switch...ine-power-tap/

    Nothing in any combination of cables to tuners etc.
    I think I'm using it correctly?? - but someone may know better??

    Whereas homemade device is perfect - 100%, AGC 4%, BER 0 and 16.0dB on both tuners
    GigaBlue UHD Quad 4K, OpenVix 5.0.35 + GigaBlue Ultra SCR-LNB 24 SCR - 2 Legacy UHD 4K LNB + Inverto DC Power Injector + Splitter to feed both Tuners. 3 FBC channels of each tuner, total 8.

  9. #23

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    Quote Originally Posted by scouse645 View Post
    I got the sky power inserter today, fitted it and thought that's sorted it, i'm afraid not, tried it before my splitter then after it, still the same problem.
    After some digging around, and as I understand it, it is not clear if the Sky 161 is to EN50494/EN50607 standards which passes 22kHz signals from the receiver to the LNB, including Unicable II LNB to set the bands. The power inserter I bought, which doesn't work, doesn't mention EN50494/EN50607 in it specifications. Neither does the GT-Sat GTPI1 Unicable / Universal LNB Power Inserter with 15V DC PSU as sold by World of Satellite.
    These units have a typical frequency range of 5 - 2200 mHz.

    Perhaps a real techie can comment??

    The only power inserter that I have found and which mentions EN50494/EN50607 is the Inverto unit - https://www.inverto.tv/accessories/3...rter-5-2400mhz

    Or a homemade one which lacks all electronic wizardry that stops the 22kHz signals, and so it works!!

    A right minefield!!
    GigaBlue UHD Quad 4K, OpenVix 5.0.35 + GigaBlue Ultra SCR-LNB 24 SCR - 2 Legacy UHD 4K LNB + Inverto DC Power Injector + Splitter to feed both Tuners. 3 FBC channels of each tuner, total 8.

  10. #24
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    Quote Originally Posted by CRMS View Post
    After some digging around, and as I understand it, it is not clear if the Sky 161 is to EN50494/EN50607 standards which passes 22kHz signals from the receiver to the LNB, including Unicable II LNB to set the bands. The power inserter I bought, which doesn't work, doesn't mention EN50494/EN50607 in it specifications. Neither does the GT-Sat GTPI1 Unicable / Universal LNB Power Inserter with 15V DC PSU as sold by World of Satellite.
    These units have a typical frequency range of 5 - 2200 mHz.

    Perhaps a real techie can comment??

    The only power inserter that I have found and which mentions EN50494/EN50607 is the Inverto unit - https://www.inverto.tv/accessories/3...rter-5-2400mhz

    Or a homemade one which lacks all electronic wizardry that stops the 22kHz signals, and so it works!!

    A right minefield!!
    Sounds very likely to me, though I admit I hadn't really thought about it before you mentioned it.

    There will be a capacitor between the in and out ports on the power inserter to pass the RF through while blocking power.
    If the value isn't chosen with passing 22kHz in mind it is likely that it won't pass 22kHz very well.

    Also there will be an inductor between the power in port and the RF port that's supposed to be receiving the power. It's supposed to stop any RF being wasted by going up the power in port rather than passing though as intended.
    Again if it's value isn't chosen with blocking 22kHz in mind it's likely that it won't block 22kHz much at all.

    Now I know that the home made power inserter didn't have an inductor and it worked but the ready made unit may also have a capacitor on the power in port to short any remaining RF to ground making the inductor essential.

    What puzzles me somewhat is that the sticky tape and copper foil capacitor in the home made power inserter was able to pass enough 22kHz.
    Maybe the fact that it was in the shield rather than the centre wire somehow meant that a good circuit at 22kHz wasn't so important.
    Zgemma H7S, 2 x single 28.2E, 1 x Freeview Hannington. Running OpenVIX (normally latest stable) with "Magic-FHD" skin.

  11. #25
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    Quote Originally Posted by CRMS View Post
    After some digging around, and as I understand it, it is not clear if the Sky 161 is to EN50494/EN50607 standards which passes 22kHz signals from the receiver to the LNB, including Unicable II LNB to set the bands. The power inserter I bought, which doesn't work, doesn't mention EN50494/EN50607 in it specifications. Neither does the GT-Sat GTPI1 Unicable / Universal LNB Power Inserter with 15V DC PSU as sold by World of Satellite.
    These units have a typical frequency range of 5 - 2200 mHz.

    Perhaps a real techie can comment??

    The only power inserter that I have found and which mentions EN50494/EN50607 is the Inverto unit - https://www.inverto.tv/accessories/3...rter-5-2400mhz

    Or a homemade one which lacks all electronic wizardry that stops the 22kHz signals, and so it works!!

    A right minefield!!
    All 3 inserters you mention specify 5 to 2000+ MHz irrespective of them being specified for unicable or not.

    The Vision inserter you have purchased does not specify any use for unicable and the data shows it powering
    i) A Quattro LNB (and not the associated switch)
    ii) A switch connected to a Quattro LNB
    iii) or both the above.

    In all cases it's the LNB to switch side of the system where the power inserter is placed and not the box to switch side of the system

    A Quattro LNB doesn't require (22kHz) control signals because the LNB outputs Vlow V, Vlow H, Vhigh V, Vhigh H in parallel.

    My guess is that you have purchased a Vision power inserter for a different application, and for a system that has been around long before the unicable became available.

    Code:
    https://catalogue.solutionsgroup-plc.com/media/vision/intergrated-reception-systems/ev5-ev9-accessories/switchable-direction-dc-inserter-line-power-tap/V5-033.pdf
    Last edited by adm; 29-07-20 at 23:32.
    Xtrend ET10K, 2 x satellite tuners 28.2 (UK Freesat channels), 2 x hybrid (UK Freeview channels)

  12. #26

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    Quote Originally Posted by CRMS View Post
    These units have a typical frequency range of 5 - 2200 mHz.
    The one you bought has a spec of 5 – 2150MHz, the one from WoS 5 ~ 2350 MHz

    Np idea if that makes any difference.

  13. #27

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    Don't think it makes any difference. On the GigaBlue SCR LNB the 24 User bands range from 1005 mHz to 2130 mHZ and I'm using Bands 1 - 8 - 1005, 1050, 1095, 1140, 1210, 1420, 1680 and 2040. Might move some of the bands to the centre anyway as there must be some roll off at the lower and upper ends of a band. Bit like a spring - using the centre part of its range.

    But I've got a couple of supplementaries:

    1. On the FBC tuners C-H, should the external power be set to Yes or No?? Or doesn't it make a difference. Physical tuners A and B are both set to Yes.

    2. For the SCR LNB Unicable II power, the GT Sat DC injector is 15v and the Inverto DC injector is 17v. The Inverto SCR LNBs specs indicate a voltage of 13.5v and 300ma??
    The GT Sat LNB I guess it is 15v as their DC injector is 15v.

    Haven't found a specified voltage for the Gigablue SCR LNB. Only 300ma current.
    I'm using 15v DC at the moment which seems to be OK and hopefully isn't cooking the LNB.
    Emailed GigaBlue but no reply, wondered if anyone knew??
    GigaBlue UHD Quad 4K, OpenVix 5.0.35 + GigaBlue Ultra SCR-LNB 24 SCR - 2 Legacy UHD 4K LNB + Inverto DC Power Injector + Splitter to feed both Tuners. 3 FBC channels of each tuner, total 8.

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