[RFI] Telephones and DSL

Aaron Kreider aaron at campusactivism.org
Mon Dec 10 00:26:06 EST 2012

I'm not an expert, but my guess is that you use a ferrite material that 
attenuates low frequencies and enough turns on the telephone cable then 
it would kill the DSL signal.

My understanding is that It attenuates everything that isn't shielded.

You might be able to pull off ferrites if you have a very strong DSL 
signal and don't need the upper part of it, and target your ferrites to 
attenuate from 1- 1.6 mhz.

At my past house I had a horrible DSL connection with a low signal to 
noise ratio.  I got cable and was much happier.  I think you can put 
ferrites on cable without a problem because the signal it is shielded 
(correct me if I'm wrong).

If you login to your DSL modem you should be able to see your signal to 
noise ratio.  If you want advice on dealing with internet issues (for 
instance what a good signal to noise ratio is) - the forums on 
dslreports.com are great.


On 12/9/2012 7:38 PM, Cortland Richmond wrote:
> Rick,
> Downstream, ADSL (up to 2.3 mbps) and ADSL2 (up to 12 mbps) spectrum 
> is as high as 1.1 MHz and ADSL2+ (up to 23 mbps) as high as 2.2 MHz.   
> If you are on 160 you could directly affect ADSL2+. You can indirectly 
> affect ADSL and ADSL2 if your RF desensitizes the DSL RF front-end.
> As long as you pass both conductors of the twisted pair through the 
> same core a ferrite should not bother it.
> Cortland
> KA5S

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