IR extender, coax splitter picture interference issue, Can anyone help?

Timmy C

Distinguished Member
I'll try and keep this brief but don't want to miss out any important detail so sorry if it's a long read for a simple question.

I ditched Sky and now have a centrally located Youview box (BT 2100) feeding TV's all around the house via HDMI extender/CAT5 baluns. The box is controlled with 'magic eyes' that feed through an SLX coax distribution amp, with an Omnilink IR signal extender kit located near the Youview box. The main Aerial feed goes directly into the youview box and all worked fine.

However, I wanted to split the aerial feed before it goes into the Youview box to feed a bedroom TV that's not connected up with the HDMI Cat 6 extension system, so bought a cheap coax splitter from ebay (see link). Aerial feed now comes down from roof, in to the splitter then one feed out to Youview and other to bedroom TV. Picture is fine in both cases and signal strength looks good according to the Youview box signal check.

The problem is, when I now point a remote at a magic eye and press a button, I get a brief picture break up so it would seem the IR signal is now somehow upsetting the Youview box. Before anyone suggests it, I don't want to use the RF out on the Youview box as it's disabled when the box sleeps unless you leave the box in high power mode 24/7 which I'm keen to avoid with todays energy prices!

My question is, have I bought a cheap rubbish splitter that's causing the issue or is it the way I have it set up that just isn't going to work? This is the one I have tried....

 

Rodders53

Distinguished Member
Well at least try using the RF pass through first to see if the IR affects the signals then. The YouView Eco mode allegedly only consumes 1W and does support RF passthrough (long boot time, though)...

But as I don't own one I can't be sure.

The splitter is a no-name Chinese item and might not be as well screened as it first appears? Perhaps? But it may be fine. It will attenuate both outputs by over half (4 dB, typically). This Triax branded one claims 3.5 dB 2 Way Splitter Metal Y Shape 2 Output Male IEC 635341443966 | eBay

The reduced signal level may be enough to allow the interference to cross-couple into the plugs sockets. Double check the plugs/sockets and couplers. Use double-screened cables. Remake any hand made plugs. Try alternative moulded fly leads.

A low gain amplified splitter might make up for the passive split - but would likely use more energy than the PVR in eco passthrough mode.
 

Timmy C

Distinguished Member
Well at least try using the RF pass through first to see if the IR affects the signals then. The YouView Eco mode allegedly only consumes 1W and does support RF passthrough (long boot time, though)...

But as I don't own one I can't be sure.

The splitter is a no-name Chinese item and might not be as well screened as it first appears? Perhaps? But it may be fine. It will attenuate both outputs by over half (4 dB, typically). This Triax branded one claims 3.5 dB 2 Way Splitter Metal Y Shape 2 Output Male IEC 635341443966 | eBay

The reduced signal level may be enough to allow the interference to cross-couple into the plugs sockets. Double check the plugs/sockets and couplers. Use double-screened cables. Remake any hand made plugs. Try alternative moulded fly leads.

A low gain amplified splitter might make up for the passive split - but would likely use more energy than the PVR in eco passthrough mode.

I was hoping you would reply as it seems you would know what's what from other posts I've seen so thank you.

I have tried using the RF out and that works fine. The trouble is the Eco mode (or Smart mode as it's now called) works in a way that you set times you use the box and it goes in to deep sleep outside of those hours and at that point it cuts off the RF out. I need it to feed a bedroom TV that is mostly used very early morning or very late night so can't have the box going in to deep sleep for more than a couple of hours in the middle of the night. When it's not in deep sleep it uses 9.2 watts which is little less than when in full operation.

I've tried alternative leads but no joy. I may well be barking up the wrong tree here but as the problem only occurs when the magic eye receives a signal, could it be the voltage making it's way to the youview box that's upsetting it? I saw this splitter {see link below) that was labelled DC pass on one side only which I assume means it's blocked on the other side. Could something like this block the IR signal reaching the RF in on the Youview box or am I talking total nonsense?

 

Rodders53

Distinguished Member
It's not a DC path issue. IR is VHF modulated signal 'backwards' from IR receive to the IR blaster (or RF2 out of a $ky box). That is relatively high level and might cause 'intermodulation' or overload type distortion within the PVR tuner(s).

Now if an aerial splitter is used correctly there should be almost nothing RF wise passing between the two outs (bedroom T V and DTR-T2100 input). But plenty back towards the IN and aerial.
https://www.farnell.com/datasheets/1770330.pdf for the vision splitters says 18dB.

I'm not convinced that I fully understand how you are wired up coax-wise though, to get the aerial AND IR return to the DTR-2100 location (for the IR blaster) on a single cable??

However, you could use a DC pass splitter to feed the bedroom TV from one of the outputs of the SLX splitter rather than splitting the aerial before it goes into the SLX splitter? DC pass would allow power to a magic eye on one leg and no magic eye on the other?

The other thing might be to use a diplexer/filter to stop VHF from reaching the DTR-T2100 input Diplexers, taps and filters - A.T.V. Poles, Brackets, Clamps & Aerials
i.e. a screened Wallplate with UHF and VHF outlets but only the UHF one used for the PVR?

Whatever moron decided on that stupid power saving 'smart feature' needs horsewhipping. It's what one gets from design by committee technically unskilled people, sadly. 9.1 W is 80 kWh per annum.
 

Timmy C

Distinguished Member
I'm not convinced that I fully understand how you are wired up coax-wise though, to get the aerial AND IR return to the DTR-2100 location (for the IR blaster) on a single cable??

However, you could use a DC pass splitter to feed the bedroom TV from one of the outputs of the SLX splitter rather than splitting the aerial before it goes into the SLX splitter? DC pass would allow power to a magic eye on one leg and no magic eye on the other?

Sorry, I didn't explain the set up very clearly. The aerial feed comes down from roof to an upstairs room which houses the Youview box, HDMI switches and splitters, the Omnilink unit with the IR repeaters pointed at various other devices that also go through the HDMI splitters to feed various TV's. This stuff all really needs to stay where it is.

So the one aerial feed goes into the Youview box. The other, whether it be from the cheapo RF splitter I bought or from the RF out of the Youview box, goes to the input of the Omnilink IR unit. The Ominilink out is then connected via coax embedded in the wall, to the input of the SLX splitter/booster that is located in a downstairs cupboard. The outputs of that then go to the TV's around the house.

So Aerial> Upstairs Youview>Omnilink> Downstairs SLX booster which then outputs to four TV's throughout house.

So the bedroom TV is already being fed from the output of the SLX but I need to split the signal before it gets to the SLX to feed the Youview box along the way.
 

Rodders53

Distinguished Member
Ah that makes more sense now.
1. So it all work fine until you introduce the splitter between the aerial and the 'as is' install.
2. It also all works fine if you split the output of the You View box, before the Omnilink?
3. You only watch Freeview or the You View recorded stuff on the other sets during periods the YV is set to be on full power on/high power standby.
4. The new bedroom TV is for use early am / late PM with no requirement for YV box viewing.

Is the infra red return interference seen on all sets connected only when viewing the YV output? Or is it also affecting simple live Freeview viewing on their own tuners? Is the bedroom TV affected?

What aerial leads are you using? Home made double screened or moulded lead? F-plugs or TV plugs?

There are three or four things I'd try;
Move / route the splitter and cable to bedroom TV as far from the hdmi/cat5/omnilink kit as possible.

Try another splitter (e.g. better screened f-plug-type), or perhaps a low gain (<8dB) powered splitter to retain the signal level into the YV box. PROception Distribution Amplifier VHF & UHF 2 Way 4dB Gain is a suitable example. Likely to be less than 1 Watt when on (it's not easy to find the power consumption specs from any of the makers).

Try a filtered (fully screened types only) UHF/VHF wallplate: YV box out into the UHF 'output' on the front panel and the cable on rear screened 'input' to feed the Omnilink/SLX magic eye amp (and thus prevent VHF IR getting into the YV box RF out) Wall plate (screened) : Diplexed (VHF/UHF) - A.T.V. Poles, Brackets, Clamps & Aerials

Note that assuming the YV box is in smart mode 12 hours a day and saves you 40 units of electric at 25p/kWh = £10 per annum. Some of the solutions may still have a fairly significant payback time (especially if they don't work).

LATE THOUGHT:
Is it possible to feed
Aerial -> Omnilink -> SLX -> bedroom -> splitter -> bedroom TV and the You View box ?

as there must be a bedroom < -- > upstairs YV box location cable??
 

Timmy C

Distinguished Member
Ah that makes more sense now.
1. So it all work fine until you introduce the splitter between the aerial and the 'as is' install.
2. It also all works fine if you split the output of the You View box, before the Omnilink?
3. You only watch Freeview or the You View recorded stuff on the other sets during periods the YV is set to be on full power on/high power standby.
4. The new bedroom TV is for use early am / late PM with no requirement for YV box viewing.

Is the infra red return interference seen on all sets connected only when viewing the YV output? Or is it also affecting simple live Freeview viewing on their own tuners? Is the bedroom TV affected?

What aerial leads are you using? Home made double screened or moulded lead? F-plugs or TV plugs?
Yes, all works fine with no splitter and everything also works if I remove splitter and use the Youviews RF out to feed the Omnilink and then on to the SLX and various TV's.

I only have the youview eco settings set in a way that it's on full power between 7pm and 10pm as those are the hours I'm most likely to switch on to watch. I may well watch at any time of day though but can live with slow boot up times at other times.

Bedroom TV most likely to be used at unusual times, i.e middle of night if can't sleep, early am, perhaps when unwell and bedbound etc.

I don't have the tuners on the rest of house TV's connected but that is something I will try. The bedroom TV actually goes through another Youview box.

Cables are a mixture of moulded and self terminated. I've always been very careful when terminating as a tiny mistake can cause the magic eyes to fail as I'm sure you know. So I had assumed, as they all work fine at all times I was ok on that front. Do you think I could be wrong? All regular TV plugs.

UPDATE: I think I've found a solution. It turns out, at some point I had run a second cable from the upstairs Youview/Omnilink room to the downstairs SLX booster cupboard. So I tried running aerial>Omnilink>SLX and then using the cheap splitter on one of the SLX outputs. So far so good but I'm yet to test the magic eyes at all locations. The picture interference when using the eye I have tested is no longer happening though so a good sign!

The reason I originally ran the second cable is the original one was causing the surge protection light on the SLX to light up, despite repeatedly remaking the plug connections. It is now doing so again now it's back in use. It doesn't seem to be causing an issue though. Should I be concerened or can I ignore it assuming everything works?
 
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Rodders53

Distinguished Member
Perfect! :clap:

Every day is a school day. I'd never heard of surge protection on an aerial amplifier before but found this SLX manual https://www.tlc-direct.co.uk/Technical/DataSheets/Philex/SLxG Amp User GuideV2sm.pdf

If it lights up then goes out after a time it's 100% normal. On permanently may be an 'earth' issue of some description - TV aerial sockets are seldom at true house earth potential and that may lead to very low, perfectly safe, currents flowing in the coax outers when interconnected. (Sometimes one can see a spark when plugging in/out). That might cause the surge indicator to light, I suspect?

NB The splitter-fed outlets will not support a magic eye (as there's no DC power path). It might (should) cause the red DC short led to light when connected...

If it doesn't t suggests it's a really nasty splitter with resistive split rather than inductive coupling (and a minimum 6dB loss = 1/4 out vs in). THAT could also account for the poor performance in the original configuration you had? Perhaps. {Resistive splitters are really rather unusual / rare nowadays.}
But resistors would still have a (poor) DC path (50 oms) to magic eyes, rather than the dead short (for DC) between centre and screen of an inductive transformer winding.

Connectors and cables are always a potential source of problems. 90-99% of issues are caused by them. Always worth checking when issues occur. I've been caught out a fair few times in my own installs. Normal room/equipment heating/cooling can cause connections to loosen/alter over time and allow interference in that a sound connection does not. Many moulded cables are of dubious construction methods and materials. Ideally cables should be double screened and of all-copper construction (core, woven braid and foil).
 

Timmy C

Distinguished Member
Thank you again for all of your input, it's very much appreciated.

As far as the surge light goes, it's definitely something to do with that particular cable as it goes out as soon as it's removed and back on whenever attached. If I plug in the other cable instead there's no surge light. Seeing as it doesn't appear to be causing an issue though and you say it's not a danger I'll leave it as is.

Yes I discovered the eyes on the split out of the SLX didn't work so put the cable for the bedroom TV and the Youview box room on the split as neither of those rooms will need an eye for this set up. The three eyes on the other SLX outputs are now tested and all appear to work with no issue.

Just for future reference though, would the splitters I have seen that are labelled DC Pass allow for eyes to also work on the split output from the SLX or not? If the answer is no, I could simply buy a 6 way SLX to replace my 4 way but that would seem wasteful if the right splitter on the output would work. It's not something I need now but perhaps in future if I wanted to change the set up in some way.
 

Rodders53

Distinguished Member
Yes the DC pass splitter will probably work...

No guarantees though as the losses (4dB on VHF return, UHF feed) and DC power demand (if power pass both ports) may mean they are unreliable?

Note some power pass are uni directional (the one you linked to is both ways - arrows on the, often red, lines indicate).
 

Timmy C

Distinguished Member
So would I take it I would need one that works both ways? Or do you mean an eye would potentially work on one side but not the other?
 

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