[mythtv-users] RF interf. gen. computer -- offtopic

Tony Maro tony at maro.net
Mon Mar 1 21:45:56 EST 2004

Andrew Dodd wrote:
> Quoting john lawler <maillist at tgice.com>:
>>I've noticed quite a bit of RF interference on radios in the house and 
>>on some electrical ground-based intercoms whenever I switch on the new 
>>myth box that I've put together. 


> Some cheapo power supplies seem to be missing powerline filtering that was
> designed into them.  (i.e. jumpers instead of chokes, filter capacitors missing).
> You may be able to solve a lot of problems with ferrite chokes placed on the
> power cables.
> Ferrite is your friend.

I've never seen a bit of difference on anything with ferrite cores. 
Ever.  But that's just me.  And I've tried them on probably 30 devices.

Anyway, he's right though, it's cheap and still worth a try.  Otherwise, 
you can try throwing a small UPS / Surge (those $40 ones) on it.  Many 
of those will filter the power going to/from the PC and if it's feeding 
that interference back out the line, it might just take care of it. 
Besides, a cheap UPS is always a good deal better than NO UPS.

Also, is your house grounded?  Many older houses have a three prong 
outlet, but the third prong doesn't go anywhere because there's no 
3-wire wiring in the wall.  Someone along the years may have replaced 
the 2 prong wall outlets with three prong, leaving the ground 
disconnected.  Proper grounding will take care of many noise problems.

Now if I could just get rid of the interference generated by my 27" TV. 
  If things aren't _just_ right, my LIRC serial remote picks up enough 
interference to scramble the signal.  Well, actually, what it does is 
feeds random numbers constantly to the port even with no IR present.  If 
I turn the TV off it goes away, and the amount of white in the screen 
affects the amount of interference.  If I set the remote sensor just 
right the problem goes away.  And no amount of ferrite core helped the 
problem, I tried.


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