Improving Digital TV signal?

FatRakoon

FatRakoon

FatRakoon

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I have knocked up a couple of Media PCs.

I have a bit of an issue that I just cannot seem to get around, and that is, that the Digital signal is always poor to them?

I have a Sony HD Recorder, that records the programs perfectly fine, the TV also gets the signal absolutely spot on, but when I try using the PC to watch and record TV, the signal is awful, and completely unwatchable?

Its not cabling. I have gone through teh cables bought new, swapped here and there and the TV and SONY NEVER have an issue and the PC NEEVER has a good signal.

I have tried various TV cards too! - In fact, in a typical me style, I have gone completely OTT buying loads of them and they all do teh same thing.

I have single, Dual and even a quad channel card, and I have PCI and more recently I bought a couple of PCIX cards, but this has not helped.

My first Media PC I knocked up was an AMD FM2 thingy, I replaced that with my Hex core 3.2Ghz AMD for a giggle and just a couple of days ago, I swapped that with an old I7-930 with the Flaming Blade Motherboard so thats not gone to waste, and its made no difference what setup I am using either.

The O/S for the Media Center is Windows 7/64 Bit and its currently using 3x4GB RAM, and I am using the old Media Center remote and the USB receiver bit from an old XP MCE setup from whenever I had that.

So, I have gone through a massive list of different hardware, the digital signal going to every other device is flawless, its only when I need it to go into a PC that it simply fails to play ball.

I am completely out of ideas!

Anyone?
 
Have you tried an active booster? perhaps the electrical noise in/around the PC is overwhelming the signal? what cable are you using? just bog standard aerial cable with hardly any shielding?
 
If your aerial cable fly-leads look like this then that's part of your problem:

51nhT-FSiCL_SY355_.jpg


Those cables are very lossy and the shielding is pants. Losing signal because switching noise from a NUC or media PC is penetrating the cable is quite common. Those fly leads also knock the stuffing out of signal level too. Decent aerial coax (WF100) loses about 0.15dB signal per metre. I've measured the cheap fly lead losses at anything up to 2dB, the equivalent of about 13m of normal coax.

Depending how you are splitting and supplying signal to the various devices, then you might also have a problem with signal noise. It's a common error to mistake signal level (Strength) with Quality.

Signal Quality is the most important thing. Boosters and active splitters don't improve signal quality. All they do is increase signal level. So a low-powered crappy signal becomes a high-powered crappy signal.

The PC card tuners are sitting bathed in PC switching noise, so their threshold of acceptable signal will be higher than is required for the TV or external recorder. It may be that tinkering around with splitters and fly lead cables will only get you so far. Your best bet might be to have an aerial guy come down and sort out a clean direct feed from the aerial so that the TV cards have the best chance of working.
 
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Ok thanks guys.

I admit that yes, I am using bog-standard cable. pretty much as the pic above, although right now, I have been using higher quality cable, but with connections, and I have tried to make the cabling as short as is feasibly possible.

Splitters.
I did originally have the cable coming in from the outside, and the connection box, I simply swapped for a dual one. This let me have one cable going to the SONY and the other cable to the TV card.
I then added a second card and then I simply made up a Y-Splitter with poundland cable and it kind of sort of worked quite well for a time.

Amplifier / Booster.
Yes, I am aware ( a little ) about the signal - its similar to mobile phones in that respect isnt it.
Anyway, yes, I have a digital signal booster and yes, its made ZERO difference. the only use it is for these days is a slightly better splitter and even then Im not sure.
I currently have that directly connected to the main calbe coming into the house instead of the original box. For wht its worth, Im using GOLD plated coaxial plugs. Probably placebo I admit.

Again, the cable going from that, to the TV Cards, is about 2 foot and then its inot a T-Splitter with the splitter cable being about 4 inches going to card number 2

Both TV Cards in there right now, are dual ( giving 4 tuners in total )

Providing signal to all devices.
How I have been doing it, is all linear in that the main cable is goingfrom the wall, to TV Card number 1, then, out of card number 1 and into card number 2 then out of number 2 into the SONY Digital HD Recorder and then into the TV.

The SONY to the TV was obviously useless as we never used the tuner of the TV and so stuck with just the sony ( or the PC ) and so we removed that.

Over time, and with trying out so many different cards, some TV Cards dont have an OUT and so then, I decided to start splitting cables.

I also notice that some cards seem to have a better reception than others, and the two cards in there right now, are mostly ok. The one card that seems to get the best reception is irritatingly,the cheap and nasty KWORLD one... The Happauge and Leadtek ones are among the worst for some reason???

The KWorld one I got from a local charity shop and some of the higher end cards I have paid well over a ton for and they are no better!

I have NOT tried any USB options, but as a thought, can you suggest a model of card that is a good one?

The option of gettign TV guy in, I might just do that... I have spent silly money getting here and its not right, so maybe had I got a guy in the first place, Id have saved myself a packet.
 
What type of aerial do you have? is it high gain (which I think is recommended for Freeview HD)?

In my experience Freeview HD (DVB-T2) tuners are a lot more sensitive to signal than the old DVB-T ones, could explain why your cheap card has better signal? not sure how modern your TV is so just guessing.
 
Each time you split or introduce a joint or use a crappy cable you knock the signal down a bit. The result is that the quality bit of the signal (the headroom) gets smaller and smaller and so closer to the noise floor. A simple splitter will knock about 3.5dB off the signal. That doesn't sound like much, but it's the equivalent of about 60% loss down each leg of the splitter's output. So it's more than halving the power.

Most TVs and tuners are happiest with a signal level at their aerial socket of around 45-65dBµV. Some will work with less. If the signal is already at the lower half of that range, and the tuner card needs say 50dBµV to operate, then adding splitters is going to throw a bit of a spanner in the works.

Oh, gold plating does naff all. It looks nice, but a 50 micro flash is too thin to make any significant contribution other that to the manufacturer's profit margin ;)
 
Yes, the aerial is fairly new, less than a year. We got it done because we wanted a cable to go to the kids rooms so they could plug in a TV and we also bought a fairly high spec aerial at the same time.

So, I wold hope, given how much it cost us, that the aerial is a good one, and that the wiring up to and into the house, is of good quality.

As for the TV, its a flat one, and its a cheap and nasty one that we got from a local Cash Generator shop. It does all the usual inputs, however I have the PC connected to it with VGA and it only lets me go to 1024x768 even though the TV when I sue HDMI goe smuch higher, its actually rubbish quality, plus I have a Bose sound system and so I have no use for the HDMI at all. Better to have a nice picture at 1024x768 than a shabby one at 1280x1024 or whatever the hell it gave me.

Erm New V Old... Yeah... I will dig out my 2 oldest ones...

I really do need 2 because we have them set to recored all Emmerdales and corries etc, but we also have some others like Russell howards or QI and so on and they often cross over, so we need it to record 2 programs at a time. If we need to watch another, we can use the SONY or hell, if I bother to tune it in, the TV.
 
Oh I agree about gold plating.
I used to be well into my pro audio and its mostly placebo I know that.
However, at the same time, when you fiddle with X and Y then there is no harm making sure that you use the best bits to at least try to get the best signal rathen using the cheapest tat you can find.

For me, Id rather have good quality stronger gold plated metals that cost me only a quid or two more, than using tatty cheap alloys that often break when I am tryign to fit them.

So again I feel better for using what I hope is the better option stuff.
 
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