Improving Freeview Signal Quality

[Willy]

Hi there,

I just bought a Humax PVR-8000, but am finding some of the channels are getting pauses etc (or occasionally just not playing at all), which I'm assuming is down to signal strength. Usually the Strength comes up around 40-50%, with Quality at 100%.

So I was wondering about how to improve the strength. Unfortunately I can't replace the arial, since I live in a big block of flats, so the options that I can see are: 1) Get a digital booster, 2) Invest in better quality cabling (I'm using fairly bog-standard coax at the moment).

Anyone know if either of these are likely to help - or whether there's another solution I'm missing?

Cheers.

Edit - Oops: think I may have put this in the wrong folder.

[nig28]

Hi
Have a word with other residents and see if they have problems, speak to the housing manager.
Make sure the aerial goes into digi box first.
Improve cableing-depends on what length you would be improving.
I not realy a believer in boosters but for £10 it might be worth a go.

Nigel

[Willy]

Thanks for the response. The cabling is only about 2m - what does that mean then? And yes, it's currently going straight into the box.

I'll ask other residents about their coverage, and see what the manager reckons too. I guess the booster has to be worth a punt at a tenner.

[sbowler]

the comunal ariel could be causing the problems, I had to have a new one fitted and its not pointing the same direction as the old one not by much but it makes a difference. I would definatley upgrade those scart leads, I did and it makes a difference, also make sure settings on box are set up to output RGB signals and that its connected to a scart on your tv which is RGB enabled. You could get an ariel company in to check the signal or fit a higher gain antenna.

[Willy]

Originally Posted by sbowler

the comunal ariel could be causing the problems, I had to have a new one fitted and its not pointing the same direction as the old one not by much but it makes a difference. I would definatley upgrade those scart leads, I did and it makes a difference, also make sure settings on box are set up to output RGB signals and that its connected to a scart on your tv which is RGB enabled. You could get an ariel company in to check the signal or fit a higher gain antenna.

Well, if it's the ariel I'm not sure there's much I can do as it belongs to the building, but I'll speak to the building manager anyway.

The scart lead is fine (it's a good one) - it's the coax cables that are a bog-standard. Oh, and the scart is plugged into the RGB scart (via a scart switcher), but I'll make sure the box is set-up as RGB-enabled.

Cheers.

[LV426]

Changing the SCART leads will have no effect whatsoever on reducing reception glitches (freezes, blocking, audio spikes).

The key to good Freeview reception is a clean RF signal going into the Freeview receiver. You get a clean signal by having a good aerial of the right type, pointed the right way, and with a half-decent downlead. Shared feeds, badly positioned aerials and/or wrong type, and poor cabling reduce strength. Whilst reduced strength does not itself cause glitches, it increases the probability that something external and electrical - a fridge thermostat, passing traffic, anything else not properly RF suppressed - will interfere sufficiently that the digital bitstream gets corrupted.

You say 100% quality; that's what is important. And you can't improve on 100%. What I suspect you have, though, is an occasional interference as I've described, that momentarily drops your quality. On analog TV this would manifest as a brief horizontal flash across the screen and perhaps a click or splutter in the audio. In the digital domain, you get a freeze or blocking. It might be worthwhile trying to find out the source of this......

[Willy]

Originally Posted by LV426

Changing the SCART leads will have no effect whatsoever on reducing reception glitches (freezes, blocking, audio spikes).

The key to good Freeview reception is a clean RF signal going into the Freeview receiver. You get a clean signal by having a good aerial of the right type, pointed the right way, and with a half-decent downlead. Shared feeds, badly positioned aerials and/or wrong type, and poor cabling reduce strength. Whilst reduced strength does not itself cause glitches, it increases the probability that something external and electrical - a fridge thermostat, passing traffic, anything else not properly RF suppressed - will interfere sufficiently that the digital bitstream gets corrupted.

You say 100% quality; that's what is important. And you can't improve on 100%. What I suspect you have, though, is an occasional interference as I've described, that momentarily drops your quality. On analog TV this would manifest as a brief horizontal flash across the screen and perhaps a click or splutter in the audio. In the digital domain, you get a freeze or blocking. It might be worthwhile trying to find out the source of this......

Hmm. Going on what you say, I have an inkling what it may be... the coax cable goes behind my TV, where there's a MASS of cables: component cables for DVD, Xbox, Gamecube; Scart for PS2, Freeview box & second Cube (!); plus a shedload of surround sound speaker cabling and optical & coax cables going to the amp. You think the interference could be causing it then? Assuming it is, I can't very well remove all those - would better coax cables maybe 'shield' the signal?

Thanks again for the responses.

[LV426]

If you get 100% quality most of the time, the it seems probable your interference is intermittent; the things you describe are likely to cause constant rather than occasional problems. Replacing your in-room cable with a length of the stuff they use for satellite downleads (it has an extra foil layer of screening in it) might just help. Worth a try. However, I'd still be looking for a thermostat or something of that broad area as the culprit. Could even be a gammy lightswitch in a neighbour's apartment...... These are just ideas to give you the concept of what might be at issue. Think broadly.

[Willy]

Great, thanks very much for the help. I'll do some investigating. Cheers all.

[nig28]

Hi
Quote "Usually the Strength comes up around 40-50%"

If the strength is at this level then it is understandable if the picture breaks-up.

Nigel

[Willy]

Originally Posted by nig28

Hi
Quote "Usually the Strength comes up around 40-50%"

If the strength is at this level then it is understandable if the picture breaks-up.

Nigel

Well, it's 52 on most channels, and plays absolutely fine. But sometimes some channels are as low as 40, and that's when I get problems. Obviously I just need to find a way to nudge it up a little.

[LV426]

Once again - despite what nig28 says.

With a digital signal, strength is not the issue. Cleanliness is. Glitches are caused by corruption of the data (dirty signal). That happens when there's some interference. Weakness of signal does not cause it. A signal can be both weak and clean and if so, will give perfect results. However, a weak signal is more prone to interference. Look for sources of interference.

[nig28]

Hi
Well if you can tell me what the symtoms of a weak signal are?

I wouldnt call the original symtoms as interference (quote) "pauses etc (or occasionally just not playing at all.

One thing I would say, if the fault is due to poor signal then it would be likely just to occur on some of the weaker stations.

Nigel

[per-Sony-fied]

I've found that if you can maintain a signal strength of 57/58% on the Humax you will not get any problems regardless if the signal is not perfect.

A RF amplifier would do the job here. Since the weaker signal is around 40 you'll need something that has a good gain and low noise... something you won't get for a tenner. There are good amps out there that give about 2dB noise for a typical gain of about 15dB which far surpass a cheapo that would give around 4.5dB of noise for about a typical gain of 13dB.

Unfortuantely where they are available from and price I'm of little help as the links to websites i had I haven't kept