Interference from digital set top box

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Hi All,

As some of you may know I had a high noise level which appeared intermittant
at first then solid.
Of recent times it has been a solid S9 on 80mx and S8 on 40mx day and
night.I guess the intermittant
part was the 11kv power lines out the front so one would think that will
continue from time to time.
In the finish, I tracked the solid interference down to a standard
definition set top digital TV box which was
in idle mode 24/7. Even when I disconnected the TV aerial leads (in/out) it
didn't change. I tried winding
the power lead on a ferrite bar and eventually the TV coax but no effect.
The plug pack is not a switching supply
either. It just plain seems the plastic cased unit radiates broadband
interference and doesn't need an aerial either.

The brand is a "KROSS" Model "DSK530STB" and I would be interested if the
same problem is noted with other
brands or models.

My noise level has dropped to S4-5 80mx (daytime) and S2-3 40mx. Big
difference to my ears.

Would be a shame if one of my neighbours bought one!!!!

73 de Peter

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Mid North Coast Amateur Radio Group Inc.
Coffs Harbour And District Amateur Radio Club Inc.
CW Operator's QRP Club Inc. No. #563
Wireless Institute Of Australia.
International Fox Tango Club.
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Re: Interference from digital set top box



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Does it have a C Tick? Maybe it would not have it through the approval
if it was actually tested.

Re: Interference from digital set top box


It costs too much to have C tick compliance, that would eat into the profits
on their 10 containers of the spugie emitting ebay rubbish.
Build a faraday cage for it.

Rob


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Re: Interference from digital set top box


Ah, it's the law.....

it also reduces the lawsuits if it has a potential  fire danger...


On Fri, 31 Aug 2007 17:08:55 +1000, <R1rob> wrote:

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Re: Interference from digital set top box


Hello chaps,

This Kross STB was purchased from Woolworth Supermarket, Park Avenue Coffs
Harbour an is supposed to be
complient with Australian regulations.

Cya Mac

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Re: Interference from digital set top box



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And the key word is "supposed", until some one complains very loudly indeed,
the authorities do not check that actual shipments comply with any
regulations.
Until companies are comprehensively fined, it is usually cheaper for them to
ignore such regulations.

MrT.



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That would explain the same C tick registration numbers on different
products....

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It depends on who holds the registration - many devices are identical but
simply "badge-engineered" for different suppliers.

The required response is clear:

1.    contact the supplier and make noises about interference, suspected
non-compliance etc,

2.    contact the ACMA area office, lodge a formal complaint (make noises
about suspect non-compliance or suspect labelling) - either pay your $60 or
get your neighbours to also complain.

Keith G Malcolm
VK1ZKM
3 September 2007



Re: Interference from digital set top box


A C-tick number (correctly known as Supplier Code Number) relates to the
Australian supplier (i.e. importer or distributor), not the product.

This means you see:

1. the same product from different suppliers but with different supplier
code numbers,

OR

2. different products all from the same supplier with the same supplier
code.

sb wrote:
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Hey Mac, are you sure the plug pack is not a switchmode PSU? The broadband
radiation you describe would seem to be more likely to eminate from a faulty
switchmode. I had a Kross STB, but I gave it to my Mum when the Thompson
unit she had suffered a failed PSU, which radiated in a similar way that you
described. She couldn't pick up any AM radio due to the interference.
Unplugging the Thompson fixed it.

I recall that the PSU on the Kross was very lightweight, so I assumed it to
be a switchmode. I didn't crack it open to find out though :)

I eventually hooked up a conventional 12v DC regulated transformer wall wart
to the Thompson, and it now works, although it does need to be unplugged
every now and then when it locks up.

The Kross is still going OK. I recall that it used to squeel and break up
when a certain light switch was turned on or off. I reduced the affect by
winding the power lead onto a ferrite core.


WR



Re: Interference from digital set top box


Oh Bugger!!!   it was a switch mode plug pack supply and thats where all the
hash came from. Used a linear supply and all clear.

Cya Peter


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Re: Interference from digital set top box


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I got caught out too with a switch mode from Jaycar, noise o plenty!


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Thought so.



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