Topband: DSL line disconnect on topband

Martin dm4im at
Wed Feb 6 13:56:00 EST 2008

There has been an article in the january-issue of cq-dl.
DL5SAF had problems with his telefones connected to a DSL-router. They 
ringed when he transmitted on 80/160.
He experimented with rectangular ferrite-cores R80-1500 and different 
He inserted the cores in every cable except the power-supply. This 
solved his problem.
He submitted screenshots which show the attenuation of the 3 different 
techniques. They were:

4 or more windings in a 8-shape, -33db on 3.75Mhz

24 windings, 12 on every long 'leg' of the core, -44db on 3.7Mhz

12 windings on one leg only, best overall results up to 50Mhz,
-32db on 3.75, -35db or better up to 30Mhz.

Find his article (in German, but screenshots and pictures are 
multi-language :-) ) here:

73, DM4iM

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