Freeview "blanks" when watching

[bottomburp]

We have Freeview and receive pretty good coverage.

Our problem is that when we are watching the tv we get "blanks" when we cannot hear what is being said, the picture carries on with no problem. It only last for 1 - 2 seconds but can be pretty annoying as we're not good at lip-reading!

Does this happen to other people? Is there anything we can do to stop this happening?

We have a TECHNIKA AESTBS7.

Thanks in advance for any help and advice.

BB

[silverfox1961]

Hi,
Unfortunately yes it does happen. Even with a digital signal, dropout can happen. This happens when you are getting signals from different transmitters and your freeview box can't cope with it and also atmospherics can affect the signal too.
I'd spend the extra cash to get freesat as it's so much better (clearer signal, more channels and no I'm not a salesman)
If you are getting crossed signals then a diplexer can help. this blocks the weaker of the two so long as you know which transmitter is the weakest.

hope that helps

[borisbeaver]

I have had this problem and it's all to do with a dodgy scart lead.

Our TV kit is on a stand on pile carpet. The underfloor is floor boards and they move. When walking around, the movement was enough to gently jog the cables causing a sound fault.

[dx100uk]

If you are getting crossed signals then a diplexer can help. this blocks the weaker of the two so long as you know which transmitter is the weakest.

???????????

really?

its a combiner not a filter.

dx

[bottomburp]

I think the diplexer route looks a bit too complicated for non-technical me! I googled it and it seems you need different ones depending on which channels are getting joint signals - all of our are suffering from this "blanking".

It certainly isn't scart or floorboard related as it happens when no-one is moving around / the tv & freeview box are on a solid base.

Being a rented house... looks like we may have to suffer! But I'll look into the costs involved with upgrading to Freesat.

All very well this digital stuff (if you're a homeowner) not quite so wonderful if you're a tenant and having to upgrade someone else's property... But in this "home-owning society" no-one seems to think about people like us

[silverfox1961]

Originally Posted by dx100uk

If you are getting crossed signals then a diplexer can help. this blocks the weaker of the two so long as you know which transmitter is the weakest.

???????????

really?

its a combiner not a filter.

dx

Quite true however a diplexer takes signals from two different aerials and combines them into one cable and stops ghosting but you get them in different groupings A/B, A/CD,B/CD. by just using one of the connections it blocks the other signals. I did just that in a previous house and it worked a treat. Of course a poorly aligned aerial could also be the problem.
Having said all that a filter will work just aswell.


fox

[SteveH2508]

Another cause of sound dropouts is electrical switching in your house - e.g. light switches; fridges etc.. A well-screened aerial cable helps to reduce it apparently.

[TTD]

Susceptible to mains-borne interference, eh?

Funny how the old, analogue technology didn't suffer the same problem. Through all the analogue televisions, VCRs and DVD recorders that I've had in my various houses, I've never had one that showed any susceptability to mains switching. Not one.

First freeview digibox (Nokia) showed exactly the symptom described in this thread. Second one (Philips) did exactly the same. Third one (Goodmans), guess what? Same again. I'm finally getting away from it with the Logik and... another make upstairs, but the first three were horendous.

Progress? Not.

[SteveH2508]

Your signal seems to be marginal at best.

Freeview/Freesat Digital TV is a good reference which explains the issue.

This is the downside to digital which the gobment don't want us to realise.

[silverfox1961]

I'm sure I read this somewhere but forgive me if I'm wrong.

At the moment the digital signal is piggybacked to the normal analogue signals resulting in lower quality of digital signal.
After the switchover the quality of digital signal will improve but you will still be getting interference from electrical equipment unless you swap your aerial cable to "screened" cable.
Normal aerial cable has an inner core and an outer braided wire. In screened cable the inner core is also wrapped in a foil which helps reduce interference.
Most satellite downlink cables are screened.

fox

[buzby]

Nope - there's no 'piggybacking' involved. Digital is in it's own segments of the band. It is true the multiplexes will be boosted in power once analogue is switched off this this was to prevent co channel interference problems, not piggybacking.

[dx100uk]

i think people are getting a liitle confused with techno-speak here.

the freeview signals are broadcast on the same band as analogue [terrestrial] tv, but are generally, as said, of a lower power.

when the switchover happens in the different regions, then the freeview transmissions will be on the more powerful transmitters [that currently carry the terrestrial signals].

interference, be it 'mains-borne' or otherwise, affects the two types of TV transmissions in different ways.

typically analogue will suffer speckling or ghosting of the image, the same cannot be said for digital, either you will get a picture or you will suffer pixalation effects or total loss, there is no in between with digital, it's either ok [1] or not [0].

as for coax, the latter day double screened [foil shielded as well as braided outer] satellite type, only provides a better signal because it is of a later design and is made from materials more suited to carrying signals at such frequencies than the old brown 'holed' braid type.

obviously, being shielded twice, there is some improvement toward nasties being picked up by the coax, but nothing can replace earthing the braid to sort those issues out.

it is worthy to note also, that many areas carry the digital signals on portions of the TV band that are far removed on the dial from those where your analogue ones are, so hence, a wideband aerial will be required, even if your freeview box reports good quality & signal.

lost count of the times i have attended a punters house who has complained of missing channels, only to find their aerial is not 'wideband' enough to get all the muxes!

dx

[dx100uk]

Originally Posted by bottomburp

We have Freeview and receive pretty good coverage.

Our problem is that when we are watching the tv we get "blanks" when we cannot hear what is being said, the picture carries on with no problem. It only last for 1 - 2 seconds but can be pretty annoying as we're not good at lip-reading!

Does this happen to other people? Is there anything we can do to stop this happening?

We have a TECHNIKA AESTBS7.

Thanks in advance for any help and advice.

BB

ok thanks for bumping a response to your original question.

honestly i know of no known reason, [associated with signal issues] that will cause such audio dropouts.

my thoughts lie with it being a setting on the box [at present thinking about audio description and the way diifferent channels have AD on one of the two strems contained in the mux].

i will download and look at the manual for that freeview box later tonight and see if anything along those lines is mentioned, i a m not fam with that box.

ofcourse we have checked the obvious haven't we?
the scart plugs are in properly?
it might be worthy to note the the audio pins are in the 18-21 range [the very far end away from the cable entry] at the pointed bit
if the scart is not 100% square in the socket & pushed firmly home , slight movement [say on bass note vibration] might create movement.

i would take out and reseat all scart cables.

there is a way to check,

most tv's & freeview boxes have more than one way to carry audio/video between devices.
how about trying a 3*RCA lphono lead [red, white, yellow]
or even a a-video lead?


dx

[buzby]

Audio drop out is VERY common, and is easily overlooked - more so than, say your picture goes 'blocky' or a whole line fails to be refreshed quickly. The cause is most likely the result of a bandwidth squeeze on the multiplex. There is minimal headroom on Freeview, and if one of the channels in the affected multiplex is having to cope with fast-changing graphics or audio, then whilst it takes up the available slack, there's nothing for the other channels in the same multiplex to use, and the audio loss is the first casualty.

Digital may be 'the future' but the adage squeezing a quart into a pint pot hold true - getting 6 channels into the space the carried one previously will have a downside when compared to analogue, which was never constrained in the same way.

[nicolee2931]

What you need to do is find out which transmitter you recieve your strongest signal from and do a manual tune on the freeview box. You need to do this as some freeview boxes are not that clever, if they pick up a weaker transmitter after they have tuned the stonger transmitter the weaker signal gets stored, where some more expensive boxes measure the C/N and CBER/VBER rate and store those the channels which provide the best signal.

You should be able to get the the Digital Channel UHF numbers and their Muxes from Welcome page | ukfree.tv - independent digital television and switchover advice, since 2002 and use the postcode checker on the right it will then list your local transmitters and their channel Muxes.

You also need the check if your aerial can receive digital channels, not all aerials can these aerials and digital channels are known as out of group channels, a good example of this is the Wrekin transmitter in Shopshire, back in the days of analogue a Group A aerial would have been used to pick up the analogue channels from the Wrekin UHF 23 - 35, but since the introduction of digital on the Wrekin the digital Muxes have been placed into Group B UHF 39 - 49, these are out of group for a Group A aerial you can just about squeeze the the first digital Mux CH 39 out of a Group A aerial the rest are just massively attenuated UHF 42 - 49, this is why a wideband aerial is very important for digital as it can see all the previous analogue groups A, B, C/D.