[Nottingham] Wireless interference

James Moore jmthelostpacket at googlemail.com
Fri Nov 16 20:24:02 UTC 2012

On 16/11/2012 20:10, Martin wrote:
> On 16/11/12 18:42, T.J long thing wrote:
>> Just a thought about external wifi interference while reading
>> comments on jason's mac problem. Can't we just line houses with
>> copper mesh thus removing the problem with interference from devices
>> outside the house, you could then connect your phone to your wifi and
>> use that to connect to the outside world. Of course this assumes your
>> phone is capable of connecting to a wifi router! TJ
> Better than that, you could use foil backed fibre panel insulation and
> have your place nicely eco-thermally insulated also.
> All well and good but as noted, unless you have your own micro-cell,
> your mobile devices become mute...
> The BIG problem about these powerline ethernet devices is that they are
> to be allowed to transmit broadband/wideband noise onto long unshielded
> mains cables (that will act as aerials) at 1000x the power presumably
> presently allowed...
> Now, you can have your lovely Faraday Cage and yet still get blasted
> from the transmissions squirting in on your mains cables...
> I consider that to be nothing short of RFI vandalism.
> Cheers,
> Martin
> Faraday Cage:
> http://en.wikipedia.org/wiki/Faraday_cage
> RFI: Radio Frequency Interference

As I've already mentioned sorta sideways-on, and I think it was 
acknowledged without prejudice, simply adequate grounding to local earth 
would eliminate wideband interference AKA bleed as it is known in HAM 
radio circles; said simple solution to the problem is demonstrably 
effective - just look at the well-configured radio gear (eg public 
broadcast masts) that emits point emissions in the range of kilowatts 
yet you could stand next to it, sit midchannel on a PMR (private mobile 
radio - usually in the 446MHz band) and still talk to your mate five 
miles away.

*Most* consumer HAM gear is not properly grounded and that's where you 
find televisions getting knocked out every time the operator keys up.

If installations were done properly using code-compliant components 
(such as those devices certified to perform within Wireless Telegraphy 
Act Licence restrictions for the band it's designed to be used in), 
there would be no need to even discuss ripping out existing thermal 
insulation and doping with copper mesh - or chicken wire! Yep, seen this 
done. Expensive.

The problem for the user begins when you bypass normal channels in 
procurement and buy non-certified, grey-market Chinese gear and offcode 
transmission cabling and think you're saving money. You end up spending 
more money trying to solve a problem that you created by cutting corners.



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