In my C/Ku band 3 metres dish I'm using combined Astrotel feedhorn (two specific LNBs) with mechanical dipole to control polarity. Yes I know it's an old configuration, but it's the unique one permitting fine skewing on all satellites in extreme orbital locations, too. So, no problem for manual control. But, if 12 volt source would be available, I could switch polarity automatically at every channel change. I believe that in Vu+ boxes the only chance to provide this voltage would be from SCART socket. Is it available any plugin to configure 12 volt output depending by channel tuned? If so, it would be possible, for example, activate 12 volt output on all vertical polarized channels, not on all horizontal, using it to close contacts in a particular interface that I'm just using to control my feedhorn. Not a common problem (I know that), but I believe it could be interesting for all satellite fans. What do you think?
Polarity control
- Thread starter Gigantone
- Start date
I am so impressed of your post and I do love it. I used to work with sats long time ago when filmnet and sky one channels with panasonic stuff were surprising all of us, young people. And you know what - your configuration was really, really unusual...and to be honest, very old even in those times 
I'm not saying get rid of it
but I'm just so surprised how people can maintain their systems to keep it working for that long time. Good for you mate!
In my opinion 12V coming out from the scart has too low current to drive your lnbs - you'll need relay with external power source to use it. But I'm sure you know what I mean saying external source
And please notice that there is couple of buttons on vu remote control which are not in use - e.g av - I'm not sure what it is for, I've never tried it before, but I think it controls pin 8 on your scart output (so it will give you 12 V when you'll press it, I assume). I'm not sure it will work when you use hdmi instead of scart ; it's probably off when hdmi is active - but you can check it out .
Get the result of your measurements and post it here please, and I'm sure we'll get the solution.
I'm not saying get rid of it
but I'm just so surprised how people can maintain their systems to keep it working for that long time. Good for you mate!In my opinion 12V coming out from the scart has too low current to drive your lnbs - you'll need relay with external power source to use it. But I'm sure you know what I mean saying external source
And please notice that there is couple of buttons on vu remote control which are not in use - e.g av
- I'm not sure what it is for, I've never tried it before, but I think it controls pin 8 on your scart output (so it will give you 12 V when you'll press it, I assume). I'm not sure it will work when you use hdmi instead of scart ; it's probably off when hdmi is active - but you can check it out .Get the result of your measurements and post it here please, and I'm sure we'll get the solution.
Hi, thank you for your kind reply. Well, I'm an old man in electronics (not in my age....), playing with satellite TV from 1989 when it was REAL SATELLITE TV! And when I say "old man" I mean coming from radio amateur bands.... you can understand. During this long period I updated my sat system many times, but I never changed main configuration. Because, if you want real satellite reception.... well, I don't believe it's too old!!! As I said, mechanical polarizer is the unique solution for a perfect skewing in all positions.
Forgot to say that my Astrotel feedhorn is now controlled by a home made interface producing pulse signal and 5 volt power supply, and it has not just manual switch for H/V exchange, but 12 volt input, too (if you send 12 volt to the input connector you get one polarity, if not the other). So, I don't need high current from SCART output, just very low one is needed to close these contacts (feedhorn is driven by this device itself). I have any Vu+ box for now (looking at Duo2 when it will be available), hoping to find a solution to provide autopolarity switching as I'm doing now with an older receiver. Unfortunately I'm not linux programmer, but if the box provides SCART 12 volt out switchable from remote control, linking this feature with channel zapping would be perfect solution (maybe a dedicated plugin could be very useful!). If not, I surely will buy Vu+ and I will switch polarity manually. Thank you.
Forgot to say that my Astrotel feedhorn is now controlled by a home made interface producing pulse signal and 5 volt power supply, and it has not just manual switch for H/V exchange, but 12 volt input, too (if you send 12 volt to the input connector you get one polarity, if not the other). So, I don't need high current from SCART output, just very low one is needed to close these contacts (feedhorn is driven by this device itself). I have any Vu+ box for now (looking at Duo2 when it will be available), hoping to find a solution to provide autopolarity switching as I'm doing now with an older receiver. Unfortunately I'm not linux programmer, but if the box provides SCART 12 volt out switchable from remote control, linking this feature with channel zapping would be perfect solution (maybe a dedicated plugin could be very useful!). If not, I surely will buy Vu+ and I will switch polarity manually. Thank you.