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View Full Version : Squeezebox and Digital TV signal don't play nice together.



givendale
2007-06-22, 18:18
Hi All,

Picture this, you spend hours in an unheated room of the house setting up the HTPC so it is a simple as possible to use and works just how you want it to.

You then get excited because you can now leave the nasty end of the house and go into the warmth of the lounge room and rack the HTPC. Give the big wind up to the significant other about how good things work and BAM, no TV. Does not look good to significant other.

Un-rack HPC and go back to Siberia, plug everything in and every thing works OK.

Go through this process several times before reaching breaking point and thinking it's the aerial cable. Replace supposedly faulty aerial cable with new one but this one travels a slightly different route. TV comes on. Then begin to move new cable into desired cable run whch travels behind AV receiver, CD, Squeezebox etc and the TV stops working. What tha..!!!???

Move cable in front of Squeezebox and TV signal works, move cable behind SB and TV stops. Leave cable behind and unplug SB and all works again. Repeat until satisfied.

Has anyone else encountered this problem?

Alternative cable run has fixed the problem for now but I am a bit baffled.

Thanks in advance for any insight.

Regards
Givendale

SuperQ
2007-06-22, 19:18
Hi All,

Picture this, you spend hours in an unheated room of the house setting up the HTPC so it is a simple as possible to use and works just how you want it to.

You then get excited because you can now leave the nasty end of the house and go into the warmth of the lounge room and rack the HTPC. Give the big wind up to the significant other about how good things work and BAM, no TV. Does not look good to significant other.

Un-rack HPC and go back to Siberia, plug everything in and every thing works OK.

Go through this process several times before reaching breaking point and thinking it's the aerial cable. Replace supposedly faulty aerial cable with new one but this one travels a slightly different route. TV comes on. Then begin to move new cable into desired cable run whch travels behind AV receiver, CD, Squeezebox etc and the TV stops working. What tha..!!!???

Move cable in front of Squeezebox and TV signal works, move cable behind SB and TV stops. Leave cable behind and unplug SB and all works again. Repeat until satisfied.

Has anyone else encountered this problem?

Alternative cable run has fixed the problem for now but I am a bit baffled.

Thanks in advance for any insight.

Regards
Givendale

what kind of signal cable are we talking about here? I assume it probably has to do with RF issues. I am going to guess this is a simple composite cable. My guess is the shielding on the cable is faulty/not enough.

SuperQ
2007-06-22, 19:21
what kind of signal cable are we talking about here? I assume it probably has to do with RF issues. I am going to guess this is a simple composite cable. My guess is the shielding on the cable is faulty/not enough.

oh.. you said digital cable.. so this is HDMI? If yes:

1. Your HDMI cable is long? Could be at the limit of how far it can go with the amount of shield it has.
2. The cable has improper shielding and is getting noise on the line. HDMI could think there is a corruption in the line and canceling signal (yay copy protection)

givendale
2007-06-23, 02:16
Sorry... should have been clearer about the cable.

This is the coaxial cable running from aerial wall connection to tuner card in HTPC. Nothing fancy just terrestrial digital TV broadcasts.

Don't know if it would affect the analogue broadcast the same way as I only have a digital tuner card.

Regards
Givendale

ceejay
2007-06-23, 03:37
Not sure where you're located but, round these parts, terrestrial digital TV is VERY sensitive to signal strength - too low, or too much interference, and the TV just stops.

Unlike good old analogue, where it would just have got a bit snowy.

Its a bit surprising that your coax RF cable is allowing itself to be interfered with (the whole idea of coax is that the design is less susceptible...) but I can easily imagine that if you have a slightly weak signal, and a not terribly sensitive tuner card, perhaps with dodgy grounding, that just a bit of extra interference could push you over the edge.

If you're at the back of your SB then you will be in close proximity to the SB's Power Supply, or more to the point the wire that goes from PS to SB - this is known to throw out lots of nasty interference, which can be reduced by things like ferrite cores on the wire, or replacing the PS with a linear unit.

However, if you've found an acceptable workaround then I'm sure you won't bother with any of these things...

Ceejay

cliveb
2007-06-23, 09:04
Sorry... should have been clearer about the cable.

This is the coaxial cable running from aerial wall connection to tuner card in HTPC. Nothing fancy just terrestrial digital TV broadcasts.
This is DVB-T broadcasts, right? Standard TV coax, which is often described as "low-loss" is anything but. For DVB signals you need to be using double shielded coax, such as CT100 or equivalent. Not only should the cable from the wall plate to the tuner card be CT100, but even more importantly so should the downlead from the aerial to the wall plate.

As to why it works when the SB3 is switched off, I suspect that even though it "works", it's borderline. The slightest interference is going to kill it: DVB signals are extremely vulnerable to interference. The SB3's stock power supply is know to spray around a fair amount of RFI, so that could be why switching on the SB3 stops it working.

givendale
2007-06-24, 00:29
Thanks both for the relpies.

I'll have a look at the CT100 cable, will let you know how I go.

Regards
Givendale

givendale
2007-07-26, 02:08
Bought the shielded cable and all good.