DSL Filtering

A. Maitland Bottoms aa4hs at amrad.org
Mon Jun 26 14:18:17 CDT 2006

Roger Geesey writes:
 > Q1: Is one filter good


 > Q2: Can the whole house line be split at the entry point into an 
 > unfiltered direct connection of the DSL modem and a single filter for 
 > all the other service?

That is how my house is wired... It was done back in the Olden Days
when phone company employees came out to do the DSL install. They
put the filter inside their half of the NIU box.

 > Q3: 

The filter blocks the DSL high frequency stuff from the phone. Just
try using a phone without it... It will annoy you but not the DSL.

 > Q4: What might be special about the phone line connection of a security 
 > monitoring system?

Hopefully nothing.

 > Q5:  Does DSL add any special considerations to RF EMI issues?

Yes, but it does seem to drop off rapidly as the distance between
the phone line and the antenna increases. I've got CAT-5 for the
in-house segment of DSL. Let's hear it for tightly twisted pair!

So I hear LF NDBs and AM broadcast with a K0BRA active antenna about
10m away from the phone lines. But, too, I do not work 160m band nor
have I heard SAQ.


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