[clug] OT: ADSL2+ and AM radio interference

Steve McInerney steve at stedee.id.au
Mon Apr 26 20:35:48 MDT 2010


reminds me of an .... incident from the early 90's. coax network years.
Secret Place rings up to suggest that someone has a bug planted on their
network, as they keep getting random network crashes.

Tech Team is sent to chase.

After much effect they eventually establish that:
* network has a loop that runs behind the tea room
* tea room has a fridge (unsurprisingly)
* fridge has a faulty condenser.
* every time the condenser kicks in, *large* electrical spike is induced
onto the network causing it to... crash.

Fridge fixed. Problem went away.

The other side of this is TEMPEST[1]. Which is way cool to watch being
Yelling at lady two floors down: "NONNONONONONONO!!!! Black Jack on the
Red Queen!!!" Solitaire... not so solo anymore.

The principles are the same. Electrical stuff radiates. Deal with it.

- S
[1] Tiny Electromagnetic Particles Emitting Secret Things

On Mon, 2010-04-26 at 00:53 +1000, Adam Baxter wrote:
> Can anyone on this list confirm or deny some of the things said on this
> post:
> http://forums.whirlpool.net.au/forum-replies-archive.cfm/369495.html
> "Interference from AM radio transmitters is a known cause of noise induction
> into the copper network."
> *  I've been getting quite a bit of radio interference when listening to ABC
> on AM. Coincidentally my ADSL sync speed and reliability has been degrading
> steadily. Are these related?
> * Are noisy AC-DC adapters to blame? If so, how can I isolate which one
> without unplugging my whole house?
> * Is there a way (other than ye-olde AM receiver) to measure where/what the
> noise is?
> * Would strategically placed ferrite "lifesavers" help or is it snake-oil?
> * Is there any way to shield the modem itself? (
> http://forums.whirlpool.net.au/forum-replies.cfm?t=369495&r=5426693#r5426693
> )
> Thanks guys.

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