DIY Power inserter

[CRMS]

I understand that there is still an issue with unicable and recordings. The solution seems to be to keep the physical tuner, say Tuner A, powered on.

Is there a simple "cable power injector" solution? A simple DIY one as shown here - http://www.satcure.co.uk/tech/dc_inserter.htm

I'm assuming that the LNB is to the left. Power could be simply taken from the 12v supply to the receiver. Then whenever power to the receiver is on, the LNB is also getting power.

And I now think that the splitter I bought is actually a power inserter:

https://www.toolstation.com/procepti...plitter/p66100

DC goes in at the top, right hand bottom to LNB and left hand bottom to receiver.

[CRMS]

Just checked the so called splitter with a multimeter. And indeed the power pass does let DC to go along the dotted line. And nothing the other way. So bottom right to LNB and bottom left to receiver.

And the receiver only appears to have 13v on the Tuner A F male plug?? Tuner B F male plug is 0v??

[CRMS]

I think I have worked out the following:
Jess is a specific design and make of Unicable and is similar to Unicable 1 and 2. Made by Jultec. https://wiki.openpli.org/Unicable_/_Jess
Unicable LNB just requires 12-13v at around 350ma, so approx 4 watts. Power to GB receiver is 12v. So can be taken from power supply lead to the power INSERTER. No need for a 240v adapter.
Legacy LNB switches 2 voltages, around 14v and 18v. Done by receiver and takes less power.
I have 2 cables from my dish at home, so an LNB with Unicable 2 and a Legacy cable would work - I think??

Anyone heard of Maclean TV Systems Unicable 2 LNB??

[scouse645]

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.

[CRMS]

That is not good to hear.
Think I'll try the DIY solution at http://www.satcure.co.uk/tech/dc_inserter.htm

[BrianTheTechieSnail]

That is not good to hear.
Think I'll try the DIY solution at http://www.satcure.co.uk/tech/dc_inserter.htm

That doesn't seem to mention any inductor to stop you losing the RF through the source of DC!
A capacitor to stop the inserted power going back towards the receiver might also be a good idea.
Similarly, further down, the one shown as a way of measuring the current doesn't show any capacitor to complete the circuit at RF frequencies.
However wrote this page didn't really seem to know what they were doing!

[Joe_90]

There's no direct DC connection to the plug end, Brian. The RF signal is capacitively coupled to the plug as described in the photos. It's all a bit "Heath Robinson-ish" but should work. Martin Pickering ran that website and shop for years and provided some excellent technical guides on electronics, aerials, cables and satellite connectivity. He retired to Crete some years ago. Still provides technical advice on Quora. Bit of an old curmudgeon and grammar nazi, but maybe that's why I always liked him!

[BrianTheTechieSnail]

There's no direct DC connection to the plug end, Brian. The RF signal is capacitively coupled to the plug as described in the photos. It's all a bit "Heath Robinson-ish" but should work. Martin Pickering ran that website and shop for years and provided some excellent technical guides on electronics, aerials, cables and satellite connectivity. He retired to Crete some years ago. Still provides technical advice on Quora. Bit of an old curmudgeon and grammar nazi, but maybe that's why I always liked him!

Ah. Designed to be buildable even if you don't have access to electronic components I guess.
Also no DC isolation if both your receiver and your dish are earthed. But that's relatively unlikely I guess.
Still nothing to stop the RF going out (or in) via the red and blue wires though.

[Huevos]

Ah. Designed to be buildable even if you don't have access to electronic components I guess.
Also no DC isolation if both your receiver and your dish are earthed. But that's relatively unlikely I guess.
Still nothing to stop the RF going out (or in) via the red and blue wires though.

I really don't understand what you are worried about. Are you a theory man looking for an inconsequential fault with this solution? If you are really worried that IF (not RF) might be leaking up the DC feed put a ferrite inline.

[BrianTheTechieSnail]

I really don't understand what you are worried about. Are you a theory man looking for an inconsequential fault with this solution? If you are really worried that IF (not RF) might be leaking up the DC feed put a ferrite inline.

When I tried to measure the current with a similar heath robinson solution I could not make it work. The receiver kept cutting off the power saying there was no signal.
I must admit I don't know if the problem was loss of signal or loss of screening meaning RF hash was getting in.
Just trying to point out that in my experience you will get nowhere with such a bodge method.

[Huevos]

When I tried to measure the current with a similar heath robinson solution I could not make it work. The receiver kept cutting off the power saying there was no signal.
I must admit I don't know if the problem was loss of signal or loss of screening meaning RF hash was getting in.
Just trying to point out that in my experience you will get nowhere with such a bodge method.

Sorry I thought you were talking about a proper solution such as the inserter sold by WoS.

[CRMS]

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??

[twol]

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??

Post tuner setup

[CRMS]

I'll have another go tomorrow. Back on Legacy. Test Match Special!!
But went through each FBC tuner - Cable to A, loop through to B, B External power Yes, Different band for each tuner.
Can also try splitting cable to A and B with 3 FB on each.
Seems that Vu+ might be the way ahead after all.

[Sicilian]

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??

Why not just use a proper purpose made power inserter? https://www.world-of-satellite.co.uk...power-inserter