1080p Display problem

MontysEvilTwin

Well-Known Member
Just noticed a new problem on my 'RE' box. The HDMI output was set to 1080i, and the TV program I was watching was in 1080p so I switched to 1080p output. The picture froze and the Humax message 'not receiving a signal or the signal is too weak came on screen'. I can watch recorded programmes in 1080p no problem, but live TV/ 1080p output does not work. Just switching back to any other mode makes the tuner start working again. I am on 1.03.12/ CFW 3.00, if this is relevant.
 

Mike2

Forum Supporter
Check you are not getting interference coupling between the HDMI cable to the TV and the aerial cable into the Humax.

Oh, bl**dy hell! Do you realize how many HDMI and aerial cables I have behind my TV? How do I keep them apart?
 

Owen Smith

Active Member
Oh, bl**dy hell! Do you realize how many HDMI and aerial cables I have behind my TV? How do I keep them apart?

It depends on how well shielded the cables are how much it matters. My HDMI and aerial cables are tie wrapped together and run parallel like that for almost 2 metres. No problems at all. But then the aerial cable is CT100 double screened satellite cable terminated with F connectors, and the HDMI cable is good quality double screened bought from Lektropaks.
 

Black Hole

May contain traces of nut
Anyone suffering from the problem of HDMI signals wiping out the UHF TV reception has a variety of potential solutions:
  • Check the aerial lead(s) are properly seated, and that the cable itself is properly connected to the plug;
  • Check the aerial signal is not attenuated by poor connections at the aerial, poor alignment, etc;
  • Check the HDMI leads are not damaged and replace if necessary;
  • Separate the aerial leads from the HDMI leads as best you can, avoid side-by-side runs;
  • Use high-quality (well screened) aerial leads and HDMI leads.
Typical symptoms are that the Humax puts up a no-signal message on screen in some or all VFORMAT options (the basic 576i setting is most likely to be OK), or the picture continues but is "blocky" with interference, and that removing the HDMI cable all together and using SCART/Phono is fine. Note that it is the Humax not the TV reporting no signal - if the identical message remains on screen after you remove the HDMI cable, then it's a problem at the TV not the Humax.
 

Owen Smith

Active Member
Note high quality well screened leads are not the same as expensive leads. I make my aerial leads myself from an old reel of CT100 I have, that plus a pair of F connectors is pretty cheap per metre, and I can make exactly the length I want. The Lektropaks HDMI cables were a bit more expensive, but still less than 20 quid per cable. Alas the particular range I bought has been discontinued, it has a semi see through outer sheath.
 
OP
MontysEvilTwin

MontysEvilTwin

Well-Known Member
The problem I had was only when outputting 1080p. Up to 1080i was fine. After untangling, the improvement was dramatic. I have since noticed though that there is still a little interference. I get some pixellation at 1080p on channels such as BBC Four HD, where the MUX is lower power. At the moment the unit is hooked up with a £1.20 HDMI cable sourced straight from China: you get what you pay for to some extent. I have now ordered some better screened cables. I don't know what difference it makes, but the problem is with an 'RE' box. If recabling does not do the trick I might swap in an old-style unit to see if this is better.
 

Owen Smith

Active Member
The reason 1080p is more of a problem is that it runs the HDMI link at double the frequency of 1080i because it has to get twice as much data down the link. This puts it into the UHF frequency range.

I'd be more inclined to blame the aerial lead. Cheap "low loss" TV coax is no good at all, the screen has gaps in it. If it isn't that but is a commerical moulded fly lead, many of these are very poorly made.
 
OP
MontysEvilTwin

MontysEvilTwin

Well-Known Member
Owen Smith hit the nail on the head. I swapped the HDMI cables but still had some interference with channels such as BBC Four HD (lower power MUX) on 1080p. I swapped the RF cable to the HDR-FOX with a better quality screened one (only £6 on Amazon) and the problem is finally fixed.
 

Owen Smith

Active Member
Note that all aerial leads should be fully screened. Why anyone ever sold these rubbish ones that aren't is a mystery to me. Probably the triumph of cost cutting beyond all reason.
 

Black Hole

May contain traces of nut
Not at all. Many people will not have had a problem with thin patch leads (the link between the aerial wall plate and the TV), and the thin type are more flexible and manageable. No trouble at all if the signal level is sufficient.

Even once we had high frequency digital signals on HDMI leads it wasn't a problem - when the TV was displaying an HDMI input from a DVD or something, it wasn't looking at the aerial input. The problem only arises when a TV is used to display HDMI from a source that is using the live aerial input, and even then shouldn't be a problem if the HDMI and aerial leads are kept separated and not wrapped together.

Owen Smith hit the nail on the head.
'Scuse me? See posts 2.
 

prpr

Well-Known Member
No trouble at all if the signal level is sufficient.
Rubbish. It's signals leaking out and in that is the problem.
Even once we had high frequency digital signals on HDMI leads it wasn't a problem - when the TV was displaying an HDMI input from a DVD or something, it wasn't looking at the aerial input. The problem only arises when a TV is used to display HDMI from a source that is using the live aerial input, and even then shouldn't be a problem if the HDMI and aerial leads are kept separated and not wrapped together.
Which is why you should have properly screened aerial cables. Sheesh, it isn't exactly difficult to comprehend.
 

Black Hole

May contain traces of nut
Typically you are not looking for the truth in what I have to say. Life is not either all black or all white.
 

Owen Smith

Active Member
Typically you are not looking for the truth in what I have to say. Life is not either all black or all white.

Consider all the other things that could be interfering with a poorly screened aerial lead. Like your 4G mobile phone at frequencies only just above some TV transmitters. Or a PC that just happens to emit those frequencies. Or if you're watching a 1080p blu ray over HDMI while your HDR Fox T2 is trying to record something.

In this case life is black and white. Cables should be properly screened, period.

I have a magic treatment for cables found to be substandard - I cut them in half so that no-one else wastes time trying to use them. Then I put them in the WEE recycle.
 

Luke

Well-Knwοn Мember
Typically you are not looking for the truth in what I have to say. Life is not either all black or all white.

So someone who describes themselves as 'black' (in a non ancestry/gene sense) is not being totally truthful because they could not be pure black?
 
OP
MontysEvilTwin

MontysEvilTwin

Well-Known Member
I did stimulate a lively debate!
'Scuse me? See posts 2.
You identified the problem. I did give you a like at the time. I untangled my leads and things improved. I then hooked up everything with higher quality, shielded HDMI leads, which did not help that much. Owen said that it was more likely to be the RF leads (before my better quality HDMI cables had even arrived) and this did fix it. I had assumed, incorrectly, that just replacing the HDMI leads would sort it out.

Thanks to both Black Hole and Owen Smith for their help.
 

Owen Smith

Active Member
It was simple logic. Most HDMI leads, even the free bundled ones, are half decent. Whereas most aerial leads, whether free or paid for, are utter rubbish.
 

Black Hole

May contain traces of nut
Regarding "low quality" aerial patch leads, what you guys are failing to acknowledge is that if the signal is good and strong it will overwhelm interference from leaky HDMI leads (or 4G - if that hasn't already broken in at the aerial). I'm not talking about the infrastructure downlink.
Note that all aerial leads should be fully screened. Why anyone ever sold these rubbish ones that aren't is a mystery to me. Probably the triumph of cost cutting beyond all reason.

Which is why you should have properly screened aerial cables. Sheesh, it isn't exactly difficult to comprehend.

Define "should". There is no "should" about it unless the user does actually have an interference problem. I have sorted out signal level problems which mystified people simply by fitting a better patch lead in place of the "thin" type, but the fact remains that the thin type is adequate in many situations and is more flexible and therefore tidier.

Your implication is that the thin patch leads are not adequate and should not be sold at all - that seems very "black and white" to me, and too proscriptive. We technical users might prefer not to use them, but the fact remains that in some cases they serve their purpose and have some advantages. What we have is a typical scenario where "experts" do not acknowledge that sometimes the cheap-and-dirty option is sufficient. A real expert keeps the cheap-and-dirty option in mind for occasions when it is appropriate.
 
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