Lights switches digital tv audio drop outs

[patong_beach]

I have just got a professional installation of quad shielded cable and new digital antenna, f-type connectors, quad sheilded leads from wall to STB. The indicator on my STB always shows full signal strength. But still, when I turn lights on and off, I get clicks in the audio. Even the clicker on my gas stove in the kitchen causes audio drop outs, using the washing machine upsets the audio also. What's going to happen in 2008 when everyone is forced to watch digital only, lets hope the technology improves in the next few years!

Does anyone know if I get an electrician to install a separate power circuit for my tv and digital box, would this fix the problem?

[Chad]

"patong_beach" <patong_beach.1bxomy@no-mx.forums.eyo.com.au> wrote in
message news:patong_beach.1bxomy@no-mx.forums.eyo.com.au...
> Does anyone know if I get an electrician to install a separate power
> circuit for my tv and digital box, would this fix the problem?

I doubt it.
I wired my 2.5hp air-con on its own circuit, and still whenever it kicks in,
i get a quick flicker on the tv and lights.
I guess the air-con is sucking up a few more amps than a common light switch
would be though.

[NFP]

patong_beach wrote:

> Does anyone know if I get an electrician to install a separate power
> circuit for my tv and digital box, would this fix the problem?

DTV is susceptible to impulse noise, so anything that creates an arc or
spark (eg switches, relays, etc) will interfere with the signal. Using
shielded cable probably helps a bit, but you still have an open antenna
that will pickup any impulse noise.

Apart from surrounding your house in an electromagnetic shield and
putting the antenna outside, I don't think much can be done. Even then,
the antenna will pickup electromagnetic interference from the
surrounding environment.

If DTV was transmitted to households via shielded cable, this might be
less of an issue, but for FTA I think you are stuck with the problem.

[OzDuDe]

NFP wrote:
> patong_beach wrote:
>
>> Does anyone know if I get an electrician to install a separate power
>> circuit for my tv and digital box, would this fix the problem?
>
>
> DTV is susceptible to impulse noise, so anything that creates an arc or
> spark (eg switches, relays, etc) will interfere with the signal. Using
> shielded cable probably helps a bit, but you still have an open antenna
> that will pickup any impulse noise.
>
> Apart from surrounding your house in an electromagnetic shield and
> putting the antenna outside, I don't think much can be done. Even then,
> the antenna will pickup electromagnetic interference from the
> surrounding environment.
>
> If DTV was transmitted to households via shielded cable, this might be
> less of an issue, but for FTA I think you are stuck with the problem.
I believe work is progressing as we notice this problem, on the problem
of impulse noise and the COFDM modulation scheme.

I also believe that the US 8-VSB system is less prone to this problem
but still not immune.

As times goes on and as 2008/12(for the UK) approaches I think we'll see
great improvement in the robustness of the COFDM system, especially when
China and Japan get their ISDB-T/DVB based systems up and running.

The Chinese effort looks very interesting indeed on the carrier issue.

Oz

[User]

i don't have this problem anymore with my digital tv but with my other
analog tv, if the washing machine is on, any machinery such as a drill or
power saw and sometimes a light switch makes my analog tv go a bit fuzzy - i
don't seem to have any problems with my digital one...whats with that?



<OzDuDe> wrote in message
news:4136ab3a$0$1876$afc38c87@news.optusnet.com.au ...
> NFP wrote:
> > patong_beach wrote:
> >
> >> Does anyone know if I get an electrician to install a separate power
> >> circuit for my tv and digital box, would this fix the problem?
> >
> >
> > DTV is susceptible to impulse noise, so anything that creates an arc or
> > spark (eg switches, relays, etc) will interfere with the signal. Using
> > shielded cable probably helps a bit, but you still have an open antenna
> > that will pickup any impulse noise.
> >
> > Apart from surrounding your house in an electromagnetic shield and
> > putting the antenna outside, I don't think much can be done. Even then,
> > the antenna will pickup electromagnetic interference from the
> > surrounding environment.
> >
> > If DTV was transmitted to households via shielded cable, this might be
> > less of an issue, but for FTA I think you are stuck with the problem.
> I believe work is progressing as we notice this problem, on the problem
> of impulse noise and the COFDM modulation scheme.
>
> I also believe that the US 8-VSB system is less prone to this problem
> but still not immune.
>
> As times goes on and as 2008/12(for the UK) approaches I think we'll see
> great improvement in the robustness of the COFDM system, especially when
> China and Japan get their ISDB-T/DVB based systems up and running.
>
> The Chinese effort looks very interesting indeed on the carrier issue.
>
> Oz

[kubalister]

patong_beach wrote:
> I have just got a professional installation of quad shielded cable and
> new digital antenna, f-type connectors, quad sheilded leads from wall
> to STB. The indicator on my STB always shows full signal strength. But
> still, when I turn lights on and off, I get clicks in the audio. Even
> the clicker on my gas stove in the kitchen causes audio drop outs,
> using the washing machine upsets the audio also. What's going to happen
> in 2008 when everyone is forced to watch digital only, lets hope the
> technology improves in the next few years!
>
> Does anyone know if I get an electrician to install a separate power
> circuit for my tv and digital box, would this fix the problem?

If the installed separate power circuit is on a completely different
power phase circuit then it could help minimise the interference
(slightly). If you only have a single phase power system in your
building then there is NO point in changing to a different sub circuit
of the same power phase. It may make the problem worse by adding extra
wiring that acts as an antenna when pulsed by changing power loads.
If you have multiple power phases in your building then you should have
lighting and power systems on different phases.

Since you're using high quality RF connectors and well shielded cable
the RF interference is entering via the antenna. So try to place the
antenna as far away as possible from the electrical wiring system of the
building (and ideally as far away from switches and loads that are
causing interference).
If you have a tiled roof then you're at a major disadvantage to those
with a steel roof as a metal roof will reflect the RF energy away from
the antenna (assuming the antenna is installed on top of the metal roof
structure).
If you have a tiled roof and still want to minimise interference then
you could install a metal foil or mesh reflector (that is grounded)
between the antenna and the direction of the electrical power wiring.

Obviously, it would be a better start to fix the source of the
interference. If your light switches have old or dirty electrical
contacts then you should replace them. Also you should ensure that the
electrical loads in the building are electrically balanced. (i.e. they
shouldn't have the current lagging or leading the voltage) Fluoro
lighting loads are usually inductive and need to be compensated by
capacitors installed in parallel with the load.
Motor loads (like those in washing machines and dryers) have a large
in-rush current when turned on and usually need well designed soft start
electronics to minimise the current surge. Higher quality white goods
will usually have better designed circuitry that minimises EM Interference.

Optionally you could install a lighting system that is switched at a
central shielded location, i.e. Clipsal C-Bus automation system that
uses dimmers and relays in a metal enclosure.

Hope this gives you some ideas.

[Fred Ferd]

"patong_beach" <patong_beach.1bxomy@no-mx.forums.eyo.com.au> wrote in
message news:patong_beach.1bxomy@no-mx.forums.eyo.com.au...
>
> I have just got a professional installation of quad shielded cable and
> new digital antenna, f-type connectors, quad sheilded leads from wall
> to STB. The indicator on my STB always shows full signal strength. But
> still, when I turn lights on and off, I get clicks in the audio. Even
> the clicker on my gas stove in the kitchen causes audio drop outs,
> using the washing machine upsets the audio also.

Ah, all that shielding. Its picking up the RFI and channelling it down into
your STB.

You can buy shield decouplers. Its an attachement that goes between the
antenna cable and the STB, at the STB.

>What's going to happen
> in 2008 when everyone is forced to watch digital only, lets hope the
> technology improves in the next few years!
>
> Does anyone know if I get an electrician to install a separate power
> circuit for my tv and digital box, would this fix the problem?

No. The RFI isnt on the power. The power supply for the STB is not passing
power line noise.


The STB is looking at the different between the inner conductor and the
shield conductor,
so the RFI on the shield is still RFI in the *signal*.

So are you meant to ground the outer three shield layers and only use the
4th layer as the signal ?

So there are four options, that might be used in conjunction.
* mast head amplifier. (This is often suggested by antenna installers even
where its not needed.. recieved power at the antenna is adequate for the
cabling run ).

* decouple the shield between cable and STB.
* ground the shield
* ground the three outer layers and use the fourth as the 2nd conductor.







>
>
> --
> patong_beach
> ------------------------------------------------------------------------
> patong_beach's Profile: http://forums.eyo.com.au/member.php?userid=15268
> View this thread: http://forums.eyo.com.au/showthread.php?t=60681
>

[o{O}o]

The worst lights you can have are halogen downlights that
run off a transformer ; also includes halogen floor or desk lamps.
If you have a halogen lamp plugged into same power point
as HT gear remove it.

I found a 3-step touchlamp gives no interference.



patong_beach wrote in message ...
>................when I turn lights on and off, I get clicks in the audio. Even
>the clicker on my gas stove in the kitchen causes audio drop outs,
>using the washing machine upsets the audio also. .............

>patong_beach
>------------------------------------------------------------------------
>patong_beach's Profile: http://forums.eyo.com.au/member.php?userid=15268
>View this thread: http://forums.eyo.com.au/showthread.php?t=60681
>

[davidred]

I had the same problem since I moved into the new house which had no aerial, so it was all running off an indoor cheap job from Dick Smith.

It didn't bother me too much as I knew the aerial was the source of the problem, so one finally got installed last week and the problem exists but only on 10HD. Any other channel (including 10SD) and I get no audio dropouts.. quite unusual.

[davidred]

I had the same problem since I moved into the new house which had no aerial, so it was all running off an indoor cheap job from d**k Smith.

It didn't bother me too much as I knew the aerial was the source of the problem, so one finally got installed last week and the problem exists but only on 10HD. Any other channel (including 10SD) and I get no audio dropouts.. quite unusual.

Well after some playing with the HD STB (Thomson 1500) I found this downmix button. No idea what it does, but the audio hasn't dropped out for quite some time when its set to LT/RT instead of LO/RO, even after repeated light flicking (2 bulbs down), frige door opening and closing, washing machine activation, etc..

Can anyone explain what the difference between LT/RT & LO/RO is?

Cheers

[Ikari]

"patong_beach" <patong_beach.1bxomy@no-mx.forums.eyo.com.au> wrote in
message news:patong_beach.1bxomy@no-mx.forums.eyo.com.au...
>
> I have just got a professional installation of quad shielded cable and
> new digital antenna, f-type connectors, quad sheilded leads from wall
> to STB. The indicator on my STB always shows full signal strength. But
> still, when I turn lights on and off, I get clicks in the audio. Even
> the clicker on my gas stove in the kitchen causes audio drop outs,
> using the washing machine upsets the audio also.

Ah, all that shielding. Its picking up the RFI and channelling it down into
your STB.

You can buy shield decouplers. Its an attachement that goes between the
antenna cable and the STB, at the STB.

>What's going to happen
> in 2008 when everyone is forced to watch digital only, lets hope the
> technology improves in the next few years!
>
> Does anyone know if I get an electrician to install a separate power
> circuit for my tv and digital box, would this fix the problem?

No. The RFI isnt on the power. The power supply for the STB is not passing
power line noise.


The STB is looking at the different between the inner conductor and the
shield conductor,
so the RFI on the shield is still RFI in the *signal*.

So are you meant to ground the outer three shield layers and only use the
4th layer as the signal ?

So there are four options, that might be used in conjunction.
* mast head amplifier. (This is often suggested by antenna installers even
where its not needed.. recieved power at the antenna is adequate for the
cabling run ).

* decouple the shield between cable and STB.
* ground the shield
* ground the three outer layers and use the fourth as the 2nd conductor.







>
>
> --
> patong_beach
> ------------------------------------------------------------------------
> patong_beach's Profile: http://forums.eyo.com.au/member.php?userid=15268
> View this thread: http://forums.eyo.com.au/showthread.php?t=60681
>



Fred Ferd, you seem to know a lot about impulse noise interference. What would you suggest to someone like me who has a STB, a generic indoor "rabbit ears" antennae and a whole lot of impulse interference? Is an RF filter of any use? What about the "shield decoupler" you mentioned? And is quad shield RG6 worth trying?

Thanks for your time